identifier	taxonID	type	CVterm	format	language	title	description	additionalInformationURL	UsageTerms	rights	Owner	contributor	creator	bibliographicCitation
4E7B8791CF6BFFBEFF36FF4011A38C2F.text	4E7B8791CF6BFFBEFF36FF4011A38C2F.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Kurmademys Gaffney, Chatterjee, and Rudra 2001	<div><p>Kurmademys.............................................. 541 Cearachelys............................................... 543 Foxemys................................................. 546 Polysternon............................................... 548</p> <p>Rosasia.................................................. 549</p> <p>Araiochelys............................................... 551</p> <p>Chedighaii barberi........................................... 553</p> <p>Taphrosphys sulcatus......................................... 556</p> <p>Taphrosphys congolensis...................................... 561</p> <p>Ummulisani............................................... 563</p> <p>Pelomedusoides Indeterminate..................................... 563</p> <p>? Galianemys sp............................................. 563 Phylogenetic Analysis............................................... 568</p> <p>Methodology................................................. 568</p> <p>Basic Taxa................................................... 570</p> <p>Character Descriptions.......................................... 571 Summary........................................................ 652 Acknowledgments................................................. 655 References....................................................... 657 Appendix 1. Morphology Description Outline.............................. 673 Appendix 2. Character List........................................... 677 Appendix 3. Data Matrix............................................ 681 Appendix 4. Skulls Measured in Appendix 5............................... 684 Appendix 5. Skull Measurements....................................... 686 Appendix 6. Additional Measurements of Bothremys and Chedighaii Skulls......... 688 Appendix 7. Additional Measurements of Taphrosphys and Labrostochelys Skulls.... 689 Appendix 8. Lower Jaw Measurements.................................. 690 Appendix 9. Apomorphy List......................................... 691 Appendix 10. Shell Measurements...................................... 696 Note Added in Proof............................................... 698</p> </div>	https://treatment.plazi.org/id/4E7B8791CF6BFFBEFF36FF4011A38C2F	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	GAFFNEY, EUGENE S;TONG, HAIYAN;MEYLAN, PETER A	GAFFNEY, EUGENE S, TONG, HAIYAN, MEYLAN, PETER A (2006): EVOLUTION OF THE SIDE-NECKED TURTLES: THE FAMILIES BOTHREMYDIDAE, EURAXEMYDIDAE, AND ARARIPEMYDIDAE. Bulletin of the American Museum of Natural History 300 (300): 1-698, DOI: 10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2, URL: http://dx.doi.org/10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2
4E7B8791CF47FF91FC8BFC7E15928ECA.text	4E7B8791CF47FF91FC8BFC7E15928ECA.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Dirqadim Gaffney & Tong & Meylan 2006	<div><p>Dirqadim, new genus</p> <p>TYPE AND ONLY INCLUDED SPECIES: Dirqadim schaefferi, n. sp.</p> <p>DISTRIBUTION: Cenomanian, Late Cretaceous of Morocco.</p> <p>ETYMOLOGY: Dir, Arabic for armor; qadim, Arabic for ancient. We are very grateful to the help of Mark Caponigro for this etymology.</p> <p>DIAGNOSIS: Euraxemydid Pelomedusoides differentiated from Euraxemys by parietal-squamosal contact present; temporal emargination less extensive; quadratojugal not exposed on temporal margin; skull shorter and wider; labial ridge broader; accessory ridge on premaxilla present; median concavity on premaxilla present; labial ridge curved, convex ventrally in lateral view; triturating surface parallel sided; accessory ridge on maxilla strongly developed; antrum postoticum smaller; prootic-opisthotic contact broader; median pterygoid contact shorter; ventral opening into canalis cavernosus just lateral to foramen posterius canalis carotici interni present; foramen posterius canalis carotici interni with prootic in margin as well as pterygoid and basisphenoid; foramen nervi vidiani not exposed in ventral view.</p> <p>DISCUSSION: See table 3 for generic comparison.</p> <p>Dirqadim schaefferi, new species</p> <p>TYPE SPECIMEN: MDEt 41, a nearly complete skull (figs. 44–53).</p> <p>TYPE LOCALITY: Eastern Morocco, Kem Kem region (figs. 14, 15). The fossil turtles (Hamadachelys, Galianemys, and Dirqadim) were collected by the local people and obtained from private collectors and dealers; their exact geological origin is therefore uncertain. However, all specimens clearly come from the Cretaceous red beds in the region called Hamada du Guir, or Kem Kem, in the southeast part of Morocco. The area is also called the Tafilalt by the local people. These terms are sometimes confusing. In fact, according to Lavocat (1954), the Hamada du Guir is a vast desert plateau east of the town of Taouz, extending from north to south, and the Kem Kem is southwest of Taouz, which is quite different from the Hamada in its structure and physiognomy (Lavocat, 1954). The vertebrate-bearing red beds, termed as ‘‘Kem Kem beds’’ by Sereno et al. (1996), outcrop along the border of the Hamada du Guir to the Kem Kem, from north of the town of Erfoud to the south for some 250 km. Along this distance, local people dig underground galleries to find vertebrate fossils, for the local and international fossil market.</p> <p>The most important work on the geology of this region was made by Lavocat in the late 1940s and early 1950s (Lavocat, 1954). The continental red beds from which the vertebrate remains are derived are represent- ed by a formation of ca. 200-m maximum thickness. They include two units: the lower unit is composed of red detritic crossstratified sandstones, of channel-fill deposits, and the upper unit is composed of red to tan sandstones intercalated with mudstones, indicating a change in sedimentation rates. Both units contain vertebrate remains. These red beds lie unconformably on the Paleozoic basement and are covered by a limestone platform formed by the Cenomanian–Turonian transgression. The vertebrate-bearing beds have therefore been termed ‘‘Infra- Cenomanian’’ by Lavocat (1954) and were long considered as Albian in age (Forey and Grande, 1998; Taquet, 1976). The base of the overlying Cenomanian–Turonian limestones in the area of Erfoud Errachidia and the Taouz region is dated by the occurrence of the ammonite Neolobites vibrayeanus (Basse and Choubert, 1959; Ferrandini et al., 1985). The vibrayeanus Zone, which is known in many parts of the Tethyan regions, corresponds to the base of the late Cenomanian (Courville et al., 1991). The age of the vertebrate-bearing red beds is therefore older than late Cenomanian, but their oldest age is not well constrained stratigraphically.</p> <p>Comparisons have been made between the vertebrate assemblage of Kem Kem beds and those from nonmarine deposits of other parts of Sahara and surrounding areas. As recognized by Lavocat (1954), the Kem Kem vertebrate fauna closely resembles that of Baharia, discovered by Stromer (1936) in Egypt. Several theropod dinosaurs, Spinosaurus and Carcharodontosaurus, and crocodilian Libycosuchus occur in both localities (Buffetaut, 1989a, 1989b, 1989c; Sereno et al., 1996; Tong and Buffetaut, 1996; Wellnhofer and Buffetaut, 1999). The Baharia assemblage was considered as Cenomanian in age by Stromer (1936). More recent works on fossil fishes from Baharia confirm Stromer’s opinion (Slaughter and Thurmond, 1974; Schaal, 1984). According to Dominik (1985), the main vertebrate-bearing bed of the Baharia Formation includes marine intercalations, and the occurrence of the ammonite Neolobites indicates a late Cenomanian age for the Baharia deposits.</p> <p>According to Sereno et al. (1996), nine elasmobranch species from the Kem Kem beds support a Cenomanian age for the deposits; seven of them occur also in the Cenomanian Baharia Formation, including four species limited to these formations (Distobatus nutiae, ‘‘ Lissodus ’’ bartheli, Markgrafia libyca, and Peyeria libyca), and one species (Serratolamna amonensis) occurs with a broad distribution and is restricted to the Cenomanian. The later species ‘‘ Serratolamna ’’ amonensis, probably called Carcharias amonensis, is indeed restricted to the Cenomanian according to Cappetta and Case (1999). Thus, even though the shark and ammonite evidence does not precisely agree, the Cenomanian age for the Kem Kem beds is now widely accepted.</p> <p>The Cenomanian Kem Kem beds have yielded abundant and very diverse vertebrate assemblages, which consist mostly of nonmarine species: fishes (Wenz, 1981; Martin 1984a, 1984b; Tong and Buffetaut, 1996; Forey, 1997; Forey and Grande, 1998; Dutheil, 1999a, 1999b; Taverne and Maisey, 1999; Cavin and Brito, 2001; Cavin et al., 2001), lizards, crocodiles (Buffetaut, 1994; Larsson and Sidor, 1999), turtles (Tong and Buffetaut, 1996; Gaffney, Tong, and Meylan, 2002), pterosaurs (Mader and Kellner, 1999; Wellnhofer and Buffetaut, 1999), and dinosaurs (Lavocat, 1951; Buffetaut, 1989a, 1989b; Russell, 1996; Sereno et al., 1996). The depositional environment is supposed to be deltaic or fluvial (Sereno et al., 1996; Cavin et al., 2001), and some fossil fishes found in one limited site indicate a still-water environment, like a lake or pool (Dutheil, 1999a).</p> <p>HORIZON: Cenomanian Kem Kem beds.</p> <p>DEPOSITIONAL ENVIRONMENT: Deltaic or fluvial (Sereno et al., 1996; Cavin et al., 2001), found with dinosaurs and other freshwater/terrestrial fauna.</p> <p>DIAGNOSIS: Same as genus.</p> <p>ETYMOLOGY: In honor of Dr. Bobb Schaeffer (1913–2004), former Curator of Fossil Fishes at the Department of Vertebrate Paleontology, American Museum of Natural History, and close friend and mentor of the senior author.</p> <p>REFERRED MATERIAL: AMNH 30038, skull lacking anterior half, Kem Kem, Morocco.</p> <p>PREVIOUS WORK: None.</p> <p>SUPERFAMILY PODOCNEMIDOIDEA COPE, 1868</p> <p>TYPE GENUS: Podocnemis Wagler, 1830.</p> <p>INCLUDED TAXA: Family Bothremydidae and epifamily Podocnemidinura (consisting of the family Podocnemididae, genera Hamadachelys Tong and Buffetaut, 1996; Brasilemys Lapparent de Broin, 2000b; and Portezueloemys Fuente, 2003).</p> <p>DIAGNOSIS: Magnafamily Podocnemidera uniquely in possession of a quadrate-basioccipital contact; prootic completely or almost completely covered ventrally by quadrate, basisphenoid, and pterygoid; dentary symphysis fused, not sutured, as in Euraxemydidae, Teneremys, and Araripemys; pectoral scales on entoplastron (except in a few Bothremydidae).</p> <p>DISCUSSION: This taxon consists of the epifamily Podocnemidinura (the Podocnemididae plus its near relatives, Hamadachelys, Brasilemys, and, presumably, Portezueloemys) and the Bothremydidae. This superfamily name is in the sense of its original author, Broin (1988), and later, Lapparent de Broin (2000b, 2001). Meylan (1996) used ‘‘Podocnemoidae’’ for this group, which we have avoided.</p> <p>EPIFAMILY PODOCNEMIDINURA COPE, 1868</p> <p>TYPE GENUS: Podocnemis Wagler, 1830.</p> <p>INCLUDED TAXA: Family Podocnemididae, genera Hamadachelys Tong and Buffetaut, 1996; Brasilemys Lapparent de Broin, 2000b; and Portezueloemys Fuente, 2003.</p> <p>DIAGNOSIS: A member of the superfamily Podocnemidoidea uniquely possessing a cavum pterygoidei formed by basisphenoid, pterygoid, prootic, and quadrate, underlain by pterygoid and basisphenoid (in contrast to fossa pterygoidea of some Bothremydidae); processus retroarticularis of articular oriented posteroventrally; basioccipital-opisthotic contact present (also in Pelomedusidae and some Chelidae, not known in Brasilemys).</p> <p>DISCUSSION: Our analysis agrees with Lapparent de Broin (2000b) and Fuente (2003) in that the close relatives of the Podocnemididae have this relationship: (Brasilemys (Hamadachelys (Podocnemididae))). We also follow their restricted use of the family Podocnemididae and do not place Brasilemys or Hamadachelys (or Portezueloemys) within it. Table 4 compares the skull in the three groups; the shell is not yet known for Hamadachelys.</p> <p>We do not use the Lapparent de Broin (2000b) name ‘‘Podocnemidoidae.’’ Instead, we create a new name, the epifamily Podocnemidinura, for the identical content and concept, even though the Lapparent de Broin name is older. The ‘‘Podocnemidoidae’’ is so close in spelling to Podocnemidoidea, which</p> <p>TABLE 4 Comparison of Podocnemidinura has a different content, that we think its continued use too confusing. This is permissible under the current rules for higher categories.</p> <p>Although we agree with Fuente (2003) that Portezueloemys is a closer relative of the Podocnemididae than either Brasilemys or Hamadachelys, we have not included it in our analysis due to the high missing values in the skull characters and because we have been unable to examine the specimen.</p> <p>Brasilemys Lapparent de Broin, 2000b</p> <p>TYPE AND ONLY INCLUDED SPECIES: Brasilemys josai Lapparent de Broin, 2000b.</p> <p>DISTRIBUTION: Albian, Brazil.</p> <p>ETYMOLOGY: For Brazil, country of origin (Lapparent de Broin, 2000b).</p> <p>REVISED DIAGNOSIS: Member of the epifamily Podocnemidinura with the cavum pterygoidei partially developed, as in Hamadachelys, but in contrast to complete as in Podocnemididae; quadratojugal-parietal contact absent, in contrast to Hamadachelys and Podocnemididae; incisura columellae auris not enclosing stapes and eustachian tube with bone, in contrast to Hamadachelys and Podocnemididae; dentary widely exposed on lateral surface of lower jaw, as in Hamadachelys, but in contrast to Podocnemididae; fossa precolumellaris shallow, in contrast to Hamadachelys and Podocnemididae; foramen jugulare posterius partially closed, in contrast to open, as in Hamadachelys and Podocnemididae; exoccipital-quadrate contact present, in contrast to Hamadachelys and Podocnemididae. See also Lapparent de Broin, 2000b.</p> </div>	https://treatment.plazi.org/id/4E7B8791CF47FF91FC8BFC7E15928ECA	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	GAFFNEY, EUGENE S;TONG, HAIYAN;MEYLAN, PETER A	GAFFNEY, EUGENE S, TONG, HAIYAN, MEYLAN, PETER A (2006): EVOLUTION OF THE SIDE-NECKED TURTLES: THE FAMILIES BOTHREMYDIDAE, EURAXEMYDIDAE, AND ARARIPEMYDIDAE. Bulletin of the American Museum of Natural History 300 (300): 1-698, DOI: 10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2, URL: http://dx.doi.org/10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2
4E7B8791CF44FF8DFD63FD1E17658ECA.text	4E7B8791CF44FF8DFD63FD1E17658ECA.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Brasilemys josai Lapparent de Broin 2000	<div><p>Brasilemys josai Lapparent de Broin, 2000b</p> <p>TYPE SPECIMEN: Museu de Geologia de Barcelona, Catalunya, Spain, MGB 37911, partial skull and partial carapace (Lapparent de Broin, 2000b).</p> <p>TYPE LOCALITY: Chapada do Araripe, Ceará State, Brazil (Lapparent de Broin, 2000b) (fig. 13).</p> <p>HORIZON: Romualdo Member, Santana Formation, Albian (Lapparent de Broin, 2000b).</p> <p>DIAGNOSIS: As for genus; see also Lapparent de Broin (2000b).</p> <p>ETYMOLOGY: For Joan Josa (Lapparent de Broin, 2000b).</p> <p>REFERRED MATERIAL: None.</p> <p>PREVIOUS WORK: Only the type description (Lapparent de Broin, 2000b).</p> <p>DISCUSSION: This partial skull and partial carapace provide enough characters for a resolution showing it as the sister taxon to Hamadachelys + Podocnemididae, a result that agrees with the branching diagram (no character matrix is presented) in Lapparent de Broin (2000b) and the computer-assisted cladogram of Fuente (2003).</p> <p>Hamadachelys Tong and Buffetaut, 1996</p> <p>TYPE AND ONLY INCLUDED SPECIES: Hamadachelys escuilliei Tong and Buffetaut, 1996.</p> <p>DISTRIBUTION: Cenomanian of Morocco.</p> <p>ETYMOLOGY: From Hamada du Guir (Tong and Buffetaut, 1996).</p> <p>REVISED DIAGNOSIS: Podocnemidinura with a partially developed cavum pterygoidei, as in Brasilemys, but in contrast to Podocnemididae; quadratojugal-parietal contact present, as in Podocnemididae, but in contrast to Brasilemys; incisura columellae auris fully enclosing stapes and eustachian tube, as in Podocnemididae, but in contrast to Brasilemys; dentary widely exposed laterally, as in Brasilemys, but in contrast to Podocnemididae; fossa precolumellaris deep, as in most Podocnemididae, but in contrast to Brasilemys; foramen jugulare posterius completely enclosed, as in Podocnemididae, but in contrast to Brasilemys; exoccipital-quadrate contact absent, as in Podocnemididae, but in contrast to Brasilemys.</p> <p>Hamadachelys escuilliei Tong and</p> <p>Buffetaut, 1996</p> <p>TYPE SPECIMEN: MDEt-T-03, a nearly complete skull and jaws.</p> <p>TYPE LOCALITY: Hamada du Guir, near Taouz, Morocco (Tong and Buffetaut, 1996).</p> <p>HORIZON: Kem Kem red beds, Cenomanian (Sereno et al., 1996; Tong and Buffetaut, 1996).</p> <p>DIAGNOSIS: As for genus; see also Tong and Buffetaut, 1996.</p> <p>ETYMOLOGY: For F. Escuillié (Tong and Buffetaut, 1996).</p> <p>PREVIOUS WORK: Tong and Buffetaut (1996).</p> <p>DISCUSSION: This taxon is represented by skull material but no shells. A significant number of characters (but not all) can be coded. The resolution in the MPC shows Hamadachelys as the sister taxon to the Podocnemididae, in agreement with Fuente (2003). Hamadachelys, as well as Brasilemys, could be included in the Podocnemididae. We exclude both from an expanded Podocnemididae to reflect current usage (e.g., Tong and Buffetaut, 1996; Lapparent de Broin, 2000b; Fuente, 2003), which is more restricted (see table 4).</p> <p>FAMILY PODOCNEMIDIDAE COPE, 1868</p> <p>TYPE GENUS: Podocnemis Wagler, 1830.</p> <p>INCLUDED GENERA: Podocnemis Wagler, 1830; Peltocephalus Duméril and Bibron, 1835; Erymnochelys Baur, 1888; Bairdemys Gaffney and Wood, 2002; Dacquemys Williams, 1954c; Neochelys Bergounioux, 1954; Shweboemys Swinton, 1939; Bauruemys Kischlat, 1994; Stupendemys Wood, 1976; Stereogenys Andrews, 1901.</p> <p>DIAGNOSIS: Member of the epifamily Podocnemidinura uniquely possessing a fully developed, medially extensive cavum pterygoidei and a dentary covered laterally by the surangular, in contrast to Brasilemys and Hamadachelys; agreeing with Hamadachelys in basioccipital-opisthotic contact (not known in Brasilemys, may be at Podocnemidinura level), incisura columellae auris enclosing stapes and eustachian tube, usually deep fossa precolumellaris, completely closed foramen jugulare posterius, and exoccipital-quadrate contact absent, all in contrast to Brasilemys.</p> <p>DISCUSSION: The formation of the family name has varied between ‘‘Podocnemididae’’ (Broin, 1977, 1988; Lapparent de Broin, 2000a, 2000b, 2001, and many earlier papers; Fuente, 2003) and ‘‘Podocnemidae’’ (Meylan, 1996). We choose to use ‘‘Podocnemididae’’, mostly because it is the name most frequently used and has the longest usage. It has been the experience of the senior author that classical authorities have different opinions on the correct root for ‘‘-nemis’’ or ‘‘-emis’’, which is usually (but not always) considered comparable to ‘‘-emys’’ (as in Emydidae). Yes, it’s true. I don’t give a rat’s ass which is used.</p> <p>EPIFAMILY BOTHREMYDINURA BAUR, 1891</p> <p>TYPE GENUS: Bothremys Leidy, 1865.</p> <p>INCLUDED TAXA: Family Bothremydidae.</p> <p>DIAGNOSIS: Same as family Bothremydidae.</p> <p>FAMILY BOTHREMYDIDAE BAUR, 1891</p> <p>TYPE GENUS: Bothremys Leidy, 1865.</p> <p>INCLUDED GENERA: Kurmademys Gaffney, Chatterjee, and Rudra, 2001; Sankuchemys Gaffney, Sahni, Schleich, Singh, and Srivastava, 2003; Cearachelys Gaffney, Campos, and Hirayama, 2001; Galianemys Gaffney, Tong, and Meylan, 2002; Foxemys Tong, Gaffney, and Buffetaut, 1998; Polysternon Portis, 1882; Elochelys Nopcsa, 1931; Zolhafah Lapparent de Broin and Werner, 1998; Rosasia Carrington da Costa, 1940; Araiochelys, n. gen.; Bothremys Leidy, 1865; Chedighaii, n. gen.; Taphrosphys Cope, 1869a; Labrostochelys, n. gen.; Phosphatochelys Gaffney and Tong, 2003; Ummulisani, n. gen.; Rhothonemys, n. gen.; Azabbaremys Gaffney, Moody, and Walker, 2001; Nigeremys Broin, 1977; Arenila Lapparent de Broin and Werner, 1998.</p> <p>DISTRIBUTION: Late Cretaceous of India, Late Cretaceous and Paleocene of Europe, Late Cretaceous and Paleogene of North and Central Africa (including Middle East), Late Cretaceous of Madagascar, Late Cretaceous and Paleocene (if Taphrosphys from New Jersey is Paleocene) of North America, Early Cretaceous of South America.</p> <p>REVISED DIAGNOSIS: Member of the superfamily Podocnemidoidea with wide prefrontals, in contrast to Pelomedusidae and Euraxemydidae, wide premaxillary depression (narrow in some Bothremydini and some Taphrosphyini); triturating surfaces highly diverse but primitively moderately wide; moderate to large palatine contribution to triturating surface (except in Taphrosphyini), in contrast to all other pleurodires except Araripemys; maxilla-quadratojugal contact present (except in Taphrosphyini); wide exoccipital-quadrate contact present, in contrast to all other pleurodires, which have narrow or no contact; processus paroccipitalis does not project posterior to squamosal, in contrast to all other Pelomedusoides; eustachian tube separated from stapes by bone, in contrast to all other pleurodires; incisura columellae auris closed and stapes contained in bony canal (except Cearachelys, Foxemys, Polysternon), in contrast to all other pleurodires; fossa precolumellaris absent (except in Kurmademys), in contrast to all other pleurodires; cavum pterygoidei as seen in Podocnemididae absent; fossa orbitalis posterior enlargement present (except in Cearachelys), in contrast to all other pleurodires; supraoccipital-quadrate contact present (except in Taphrosphyini and Zolhafah); prootic partially or completely covered in ventral view; foramen posterius canalis carotici interni not in prootic, in contrast to Araripemydidae, Chelidae, and Pelomedusidae; basisphenoid-quadrate contact present, as in Podocnemididae, but in contrast to all other pleurodires; high lingual ridge on lower jaw.</p> <p>PREVIOUS WORK: In 1891, George Baur recognized three living families of pleurodires, the Sternothaeridae (the Pelomedusidae of former usage), the Podocnemididae, and the Chelyiidae (Chelidae of current usage) (Baur, 1891: 420). Based on the presence of deep pits in the jaws, which he thought might be alveoli for large tusks, he thought that Bothremys Leidy should be placed in a family of its own, and he coined the term Bothremydidae (Baur, 1891: 424). Thus, Baur’s (1891) Pleurodira consisted of four families rather than the two that have been recognized for much of the last century.</p> <p>Baur (1893) reiterated the uniqueness of the Bothremydidae and used the superfamily name Pelomedusoidea for a group of three of his four pleurodire families: the Pelomedusidae, which he restricted to two genera, Pelomedusa and Sternothaerus (5 Pelusios); the Podocnemididae, in which he placed Podocnemis, Peltocephalus and Erymnochelys; and ‘‘the intermediate extinct family Bothremydidae’’. This is very close to the current usage developed for ‘‘Pelomedusoides’’.</p> <p>Baur’s Bothremydidae was adopted by Hay (1908) in his classic monograph on North American fossil turtles. It was also used by Nopcsa (1923) and Dollo (1924) but then nearly disappeared from use for about 65 years. In his treatment of North American bothremydids, Hay (1908) included Bothremys Leidy, Taphrosphys Cope, and two new genera, Amblypeza and Naiadochelys (both considered invalid here). Schmidt (1940), in his description of Podocnemis barberi (now Chedighaii barberi), assigned his new taxon to a Pelomedusidae, which he acknowledged was used in an inclusive sense. He specifically mentioned the Bothremydidae, stating that Taphrosphys, which was placed in the Bothremydidae by Hay (1908), may be allied to Podocnemis, but he left the issue of revision of the Pleurodira for future workers.</p> <p>Carrington da Costa (1940) tentatively referred his new genus Rosasia to the family Pelomedusidae and the ‘‘subfamily’’ Bothremydidae. He was explicit in his conclusion (apparently in consultation with F.-M. Bergounioux) that the Bothremydidae should be treated as a subfamily. He contemplated referring Rosasia to the Bothremydidae again in 1958 (Carrington da Costa, 1958), but instead referred it to the Pelomedusinae. Williams (1950) used Bothremydinae as a subfamily of the Pelomedusidae, along with the Pelomedusinae. However, in the turtle classification of Romer (1956), which was significantly influenced by Williams, the Bothremydinae is gone; only the Pelomedusidae and Chelyidae make up the Pleurodira.</p> <p>Baur’s Bothremydidae appeared next in a review of the genus Bothremys (Gaffney and Zangerl, 1968), which was prompted by the discovery of the first skull–shell association of a bothremydid, a specimen of Bothremys (now Chedighaii) barberi from the Selma Formation of Alabama. In this paper several shell taxa previously assigned to Podocnemis were referred to Bothremys. Although formal recognition of the family Bothremydidae was deferred, the uniqueness of the Bothremys lineage was noted. Gaffney (1975b) gave the group formal recognition as a subfamily of the Pelomedusidae. The subfamily was formally resurrected for the genera Taphrosphys and Bothremys in this paper, which gave a detailed description of the shell of Taphrosphys from the Late Cretaceous (now considered Paleocene) of New Jersey.</p> <p>This family group name was also briefly considered by Broin (1977) in her treatise on French fossil turtles. In that work she reviewed the higher categories of pleurodires and considered the taxonomy of Baur (1888, 1891) to be the most satisfactory. She suggested that reuniting the genera Bothremys, Nigeremys, and Taphrosphys in the Bothremydidae would be desirable, but she did not follow the lead of Gaffney (1975b) until she published a further review of fossil pleurodires (Broin, 1988). In this stratigraphic treatment of geographic dispersion of pleurodires, she referred a series of genera to the family Bothremydidae, which she included in the hyperfamily Pelomedusoides along with the Podocnemididae. The genera referred to the Bothremydidae included Taphrosphys, Bothremys, Nigeremys, Rosasia, Apertotemporalis, Apodichelys, and Sokotochelys (Broin, 1988). We consider the last three to be invalid or incertae sedis.</p> <p>The redescription of the bothremydid Rosasia by Antunes and Broin (1988) provided the first review of the family Bothremydidae. It included a tentative phylogeny and a detailed description of the skull of Rosasia, a taxon that was previously known only from shell material. The cladogram showed that the Bothremydidae is the sister group of the Podocnemididae. Furthermore, within the Bothremydidae, Bothremys, Nigeremys, and Taphrosphys informal groups were recognized. However, the phylogenetic position of many named taxa, especially those known only from shells, remained unresolved. The genera treated as members of the Bothremydidae in Antunes and Broin (1988) included Apodichelys, Apertotemporalis, Bothremys, Elochelys, Nigeremys, Rosasia, and Taphrosphys.</p> <p>In Antunes and Broin (1988), the Bothremydidae was characterized by five skull, seven shell, and one vertebral character. Skull characters included (Broin’s character numbers) (C 1) eustachian tube excluded from stapedial canal by quadrate, (C 2) strong development of the jaws and vomer, and secondary closure of temporal and cheek emargination, (C 3) low wide external narial openings, (C 4) ventral coverage of the prootic by the pterygoid, and (C 5) flattening of the anterior part of the muzzle. Shell features characteristic for the family included (C 6) large and depressed form of the subquadrangular carapace, with a smooth semicircular arc without inflations or keels and a trapezoidal ventral profile, (C 7) anterior plastral lobe particularly short and wide at its base, trapezoidal or subtrapezoidal, (C 8) vascular sculpture of the carapace consisting of dichotomous (branching) grooves well developed, and more so in the marine Taphrosphys group, (C 9) frequent suturing of the ilium to the suprapygal (this was considered to be a reversal to the primitive condition), (C 10) reduction in the number of neurals to seven or fewer, which is acknowledged to occur several times in pleurodires, (C 11) reduction of the width of vertebral 1, which does not cover all of the nuchal bone, and with the following vertebrals having an anterior width less than or equal to their median length (parallelism in this character was acknowledged), and (C 12) pectoral–abdominal sulcus crossing the anterior part of the mesoplastra (parallelism in this character was acknowledged). A single character of the vertebrae (C 13) was acknowledged to be variable in the three taxa for which cervical vertebrae were known.</p> <p>In the same paper, the Bothremys group of the Bothremydidae was characterized by three skull and two shell characters: (D 1) maximum enlargement of the triturating surfaces with a deep fossa present in the palatine and jugal and in the dentary, (D 2) secondary covering of the cheek emargination by posterior extension of the maxilla, ventral enlargement of the quadratojugal, and anterior expansion of the quadrate, (D 3) foreshortening of the bones at the back of the skull, particularly the supraoccipital, the basisphenoid, and the basioccipital, such that the occipital condyle is in line with the articular facets of the quadrate, (D 4) tendency for elongation of the bridge, and (D 5) formation of a more-or-less strongly developed nuchal embayment that affects the nuchal scute.</p> <p>The Nigeremys group was characterized by four characters: (F 1) deep ventral premaxillary pit but without formation of a recurved beak, (F 2) deep carotid fossa in the area of the quadrate–basisphenoid suture, (F 3) flattening and anterior enlargement of the snout with pronounced posterior elevation of the skull roof with a tectiform or subtectiform profile, and (F 4) marked increase in size.</p> <p>Nearly all of these characters from Antunes and Broin (1988), or modifications of them, have been used in the dataset presented here (appendices 2 and 3). This work provided the basis for future analyses of the Bothremydidae.</p> <p>A byproduct of Meylan’s (1996) phylogenetic analysis of Araripemys was the first computer-assisted cladistic analysis of the Bothremydidae. Three bothremydids with available skull information were included in that analysis: Bothremys, Rosasia, and Taphrosphys. The Bothremydidae was monophyletic in this analysis and was the sister group of the Podocnemididae, as suggested by Antunes and Broin (1988) and Broin (1988). Beginning with this work, paleontologists have generally followed the taxonomy of Baur (1891) as suggested by Broin (1988) in recognizing more family-level taxa in the pleurodires. Neontologists have generally followed this development by splitting the living Pelomedusidae (sensu lato) into a more restricted Pelomedusidae and recognizing the family Podocnemididae (Pough et al., 1998, 2001; Zug et al., 2001).</p> <p>In her description of Brasilemys, Lapparent de Broin (2000b) provided an explicit hypothesis for the phylogenetic position of the Bothremydidae. This family, including an undescribed form from Erfoud, Hamada de Guir, Morocco (now known as Galianemys Gaffney, Tong, and Meylan, 2002), was argued to be the sister group of the Podocnemididae plus the genera Hamadachelys and Brasilemys, a group that she termed the Podocnemidoidae (here renamed the Podocnemidinura).</p> <p>A diverse fauna of bothremydid turtles was described by Lapparent de Broin and Werner (1998) from the Maastrichtian of Egypt. They described what they thought to be five taxa representing three separate lineages of bothremydid turtles. Two were described from skulls and three from shell fragments. Their new genus Zolhafah was based on a single skull and allied with members of the ‘‘ Bothremys group’’, Bothremys and Rosasia. A second new genus, Arenila, was based on a poorly preserved skull and allied with Nigeremys in the ‘‘ Nigeremys group’’. A carapacial disc was also provisionally referred to this new taxon. Two other poorly known genera, Sokotochelys and Apertotemporalis (here considered nomina nuda), were referred to this group. The ‘‘ Taphrosphys group’’ was represented by two carapace fragments.</p> <p>Lapparent de Broin and Werner (1998) characterized the skull of members of the Bothremys group as having pits in the triturating surface and as having a tendency to a flat posterior palatal surface with reduction of the ‘‘podocnemidoid fossa’’. Lapparent de Broin and Werner (1998) characterized the shell of this group as ‘‘a rather wide rectangular-rounded shell with a notched nuchal, an anterior trapezoidrounded [plastral] lobe, short and posteriorly wide, a posterior [plastral] lobe narrower at its base than the anterior lobe and with straight posteriorly converging borders.’’</p> <p>They characterized the skull of members of the Nigeremys group as having: (1) a much enlarged depression in the area of the pterygoid-basisphenoid and pterygoid-quadrate suture (this depression, the fossa pterygoidea, was considered by them to be homologous to the ‘‘podocnemidoid fossa’’ or cavum pterygoidei, a conclusion we dispute), (2) an enlarged snout, (3) basioccipital participating in occipital condyle, and (4) an enlarged and posteromedially projecting trochlear process (here interpreted as an artifact of preservation in Arenila). The shell of members of the Nigeremys group differed from other podocnemidoids in having the axillary buttress cross the second rather than the third peripheral to reach the first costal bone.</p> <p>Lapparent de Broin and Werner (1998) relied entirely on shell characters to distinguish the Taphrosphys group for which they said skulls were too poorly known. Referral of new fossil shell material appeared to be based largely on the ‘‘typical very marked decoration of small prominent polygons and granulation and rounded crests.’’ Elochelys and Taphrosphys were reported to share a shell that is ‘‘elongated rounded ovoid anteromedial shell, intergular separating the gulars and meeting the pectorals, rounded posterior lobe in most Taphrosphys specimens and in Elochelys, well trapezoid anterior lobe.’’ They considered Gafsachelys Bergounioux, 1956 to be a member of this group on the basis of shell decoration.</p> <p>These authors suggested that the shell shapes common to the Taphrosphys and Bothremys groups indicated that they formed a monophyletic sister group to the Nigeremys group (Lapparent de Broin and Werner, 1998: 164). This was a refinement of the trichotomy indicated for these groups in Antunes and Broin (1988).</p> <p>Since 1998, the number of genera referred to the Bothremydidae has more than doubled. In addition to Zolhafah and Arenila discussed above (Lapparent de Broin and Werner, 1998), Tong et al. (1998) described the French bothremydid Foxemys and presented a cladogram with a resolution of (Foxemys (Taphrosphys (Bothremys, Rosasia))), a result (provided by the senior author) that is inconsistent with our current results, due to the smaller data set. More recently, Gaffney and colleagues have described six additional genera. Phosphatochelys (Gaffney and Tong, 2003) was described on the basis of a single skull of a short-faced member of the Nigeremys group. Another new member of the Nigeremys group is the remarkable skull taxon Azabbaremys from the Paleocene of Mali (Gaffney, Moody, and Walker, 2001). The large and strongly roofed skull of the type is quite similar in many respects to Nigeremys itself. The oldest bothremydid described to date is the Albian genus Cearachelys (Gaffney, Campos, and Hirayama, 2001), which was described from two nearly complete skeletons from the Chapada do Araripe in Ceara, Brazil. The three well-preserved skulls and shells of this taxon provide excellent evidence for the primitive skeletal morphology of the family. This taxon was referred by its describers to the Bothremys group of Lapparent de Broin and Werner (1998). A morphologically similar and apparently related genus, Galianemys (Gaffney, Tong, and Meylan, 2002), has been described from the Cenomanian Kem Kem Redbeds of Morocco. The two Indian bothremydids Sankuchemys (Gaffney et al., 2003) and Kurmademys (Gaffney, Chatterjee, and Rudra, 2001) considerably extend the geographic range of the Bothremydidae.</p> <p>DISCUSSION: As a result of the discovery of many new bothremydid skulls that are used as the basis for a phylogenetic analysis of the Bothremydidae presented here, four monophyletic groups are recognized as tribes within the Bothremydidae (figs. 1, 2; table 5). The idea of the ‘‘ Bothremys group’’ has been documented and confirmed in this analysis, but the ‘‘ Nigeremys group’’ and ‘‘ Taphrosphys group’’ of Lapparent de Broin and Werner (1998) are combined in the tribe Taphrosphyini.</p> <p>The possible extension of the Bothremydidae into the Miocene is based on a single questionable record. Roger et al. (1994) reported on a damaged braincase from Miocene rocks from Oman in the Arabian Peninsula. The braincase, an uncataloged specimen with no institutional collection indicated, was not described in detail and was figured only in ventral view, but it was reported to have a ‘‘fosses ptérygoido-carotidiennes obliques’’ (Roger et al., 1994: 11) and an incisura columellae auris separated</p> <p>TABLE 5</p> <p>Tribes of Bothremydidae from the eustachian tube. Unfortunately, we have been unable to see this specimen and cannot confirm these characters. The photograph (Roger et al., 1994: pl. 1, fig. 1) shows a worn braincase in ventral view that certainly has large depressions in the position of what we would call the fossa pterygoidea. This is a character found in only a few bothremydids as a deep fossa, namely Foxemys, Polysternon, Nigeremys, and Arenila. However, the specimen is clearly eroded on its surface and it is possible that the fossae are actually cavum pterygoidei, with the ventral covering eroded away along the anterior and medial edges, making this a podocnemidid and not a bothremydid character. There is some evidence for this conclusion in the photograph, which shows the two depressions with different shapes, requiring at least some erosion on the right fossa. The second character, the closed incisura columellae auris, is restrict- ed only to bothremydids and does not occur outside the group. However, this character is not visible in ventral view. Furthermore, the specimen is eroded extensively on both sides and is missing most if not all of each cavum tympani, so this character may not be determinable at all in this specimen. It is unfortunate that this specimen is not available for further study, as it represents the best possibility for bothremydids extending past the Eocene. As it stands, however, the published claim, while certainly possible, is inadequate for a range extension past the Eocene into the Miocene.</p> <p>a Except Araiochelys.</p> <p>b Except</p> <p>Zolhafah.</p> <p>c Except Foxemydina.</p> <p>d</p> <p>Except Polysternon.</p> <p>e Except</p> <p>Labrostochelys.</p> <p>f</p> <p>Except in a few species.</p> <p>Extension of the range of bothremydids into the Late Cretaceous of Madagascar is based on the report of Gaffney and Forster (2003). This consists of a partial lower jaw (fig. 247) that has the symphyseal edge and lateral pits typical of the tribe Bothremydini.</p> <p>A short, wide anterior lobe of the plastron has been used as a diagnostic character for the Bothremydidae (Broin, 1977, 1988; Lapparent de Broin, 2000a, 2001). However, Bairdemys venezuelensis has a short, wide anterior plastral lobe and a plastral morphology (fig. 275) that is very similar to that in such bothremydids as Chedighaii (fig. 264). However, Bairdemys is clearly a podocnemidid based on the skull morphology (Gaffney and Wood, 2002). Therefore, this character is not diagnostic for the family Bothremydidae and the records based on this feature are in doubt.</p> <p>SUBFAMILY KURMADEMYDINAE, NEW</p> <p>TYPE GENUS: Kurmademys Gaffney, Chatterjee, and Rudra, 2001.</p> <p>INCLUDED GENERA: Kurmademys Gaffney, Chatterjee, and Rudra, 2001; Sankuchemys Gaffney, Sahni, Schleich, Singh, and Srivastava, 2003.</p> <p>DIAGNOSIS: As for tribe Kurmademydini.</p> <p>TRIBE KURMADEMYDINI, NEW</p> <p>TYPE GENUS: Kurmademys Gaffney, Chatterjee, and Rudra, 2001.</p> <p>INCLUDED GENERA: Kurmademys Gaffney, Chatterjee, and Rudra, 2001; Sankuchemys Gaffney, Sahni, Schleich, Singh, and Srivastava, 2003.</p> <p>DISTRIBUTION: Late Cretaceous Maastrichtian of Peninsular India.</p> <p>DIAGNOSIS: Bothremydid pleurodires with the following unique characters: extreme degree of posterior temporal emargination characterized by a short postorbital and no parietal-quadratojugal contact; large fossa precolumellaris (unknown for Sankuchemys); condylus mandibularis well anterior to main body of basioccipital; small part of prootic exposed on ventral surface at junction of basisphenoid, pterygoid, and quadrate, containing foramen nervi facialis; other differen-</p> <p>TABLE 6</p> <p>Genera of Kurmademydini tiating characters are: preorbital part of skull narrow, in contrast to Bothremydini; jugal-quadrate contact absent and supraoccipital-quadrate contact (unknown for Sankuchemys) present, in contrast to Taphrosphyini; foramen stapedio-temporale not very close to foramen nervi trigemini, in contrast to Bothremydini and Taphrosphyini; fenestra postotica closed, in contrast to Cearachelyini; basisphenoid pentagonal, in contrast to Cearachelyini; jugal not retracted from orbit, in contrast to Cearachelyini; triturating surfaces narrower than in Bothremydini; parietal contacts pterygoid (unknown for Sankuchemys, also occurs in some Bothremydini and Taphrosphyini).</p> <p>DISCUSSION: The sister-group relationship of Kurmademys and Sankuchemys becomes unresolved at two steps in the MPC (fig. 288). The most serious problem is the flattened Sankuchemys skull, preventing nearly all quadrate characters from being determined. The two taxa are united only on the basis of the temporal emargination and the exposure of the quadrate-pterygoid-basisphenoid contact, both of which appear a number of times within pleurodires. Nonetheless, when the tribe Kurmademydini becomes unresolved, these two genera are still sister taxa to the subfamily Bothremydinae (consisting of the tribes Cearachelyini, Bothremydini, and Taphrosphyini), which holds together for three steps. Table 6 compares the two genera Sankuchemys and Kurmademys.</p> <p>The phylogenetic analysis of the tribe Kurmademydini (essentially just Kurmademys, as Sankuchemys is poorly preserved) shows it as the sister group to the remaining Bothremydidae. In geographic and stratigraphic terms, this is surprising, as the Kurmademydini is Asian and Maastrichtian, while the oldest bothremydids (Cearachelys) are South American and Albian and the next oldest (Galianemys) are African and Cenomanian. Furthermore, the tribe Cearachelyini, which contains these bothremydids, also has skull morphology that seems more plesiomorphic for bothremydids than for the kurmademydines. However, the emarginated skull and the deep fossa precolumellaris of Kurmademys are primitive for Pelomedusoides, and the Cearachelyini have such subfamily Bothremydinae synapomorphies as the anteriorly opening foramen stapedio-temporale (fig. 309), large postorbital, maxilla-vomer contact, as well as slight temporal emargination and small or absent fossa precolumellaris. So at the present time, the Kurmedemydini are relatively well-supported as sister taxa to all remaining bothremydids. This indicates that the biogeographic history of the bothremydids is more complex than some recent workers would suggest (e.g. Lapparent and Werner, 1998). The senior author hopes to provide a biogeographic hypothesis for bothremydids in the near future that reflects the cladogram presented here.</p> <p>Kurmademys Gaffney, Chatterjee, and</p> <p>Rudra, 2001</p> <p>TYPE AND ONLY INCLUDED SPECIES: Kurmademys kallamedensis Gaffney, Chatterjee, and Rudra, 2001.</p> <p>DISTRIBUTION: Maastrichtian of southern India.</p> <p>ETYMOLOGY: Kurma, ‘‘turtle’’ in Sanskrit, in allusion to the second-stage incarnation of Lord Vishnu as a turtle in Hindu mythology.</p> <p>REVISED DIAGNOSIS: Bothremydid of the tribe Kurmademydini with extensive temporal emargination seen also in Sankuchemys but absent in all other Bothremydidae; differing from Sankuchemys in having a smooth, expanded triturating surface rather than a narrower one with an accessory ridge; foramen posterius canalis carotici interni in basisphenoid unique among Bothremydidae; foramen stapedio-temporale visible in dorsal view in contrast to all other bothremydids (unclear in Sankuchemys). Carapace low and oval; shell surface texture weak granulated polygons; six neurals, sixth to eighth costals meeting on the midline; plastron with anterior lobe longer than in Bothremydini and Taphrosphyini; bridge longer than anterior and posterior plastral lobes; posterior plastral lobe short; humeropectoral sulcus posterior to epihyoplastral suture, crossing entoplastron; pectoroabdominal sulcus far anterior to mesoplastron, as in Araiochelys; pubic and ischiac scars as in Bothremydini.</p> <p>DISCUSSION: Kurmademys is well known from a series of skulls and postcrania, including a shell (figs. 255–257) that provides most of the characters for the tribe Kurmademydini in the dataset. The other postcrania have not yet been studied. Comparison with Sankuchemys is given in table 6.</p> <p>Kurmademys kallamedensis Gaffney,</p> <p>Chatterjee, and Rudra, 2001</p> <p>TYPE SPECIMEN: ISI R152 (figs. 56, 57, 63, 64, 282B), a nearly complete skull lacking the dorsal part of the prefrontals, the posterior part of the crista supraoccipitalis, and part of the left quadratojugal.</p> <p>TYPE LOCALITY: Near the village of Kallamedu, Tamil Nadu, southern India. Map of locality is in Sastry et al. (1972) (fig. 12).</p> <p>HORIZON: Kallamedu Formation of the Ariyalur Group. Formation named and described by Sastry et al. (1972), who correlated it with the uppermost Maastrichtian; the Cretaceous–Tertiary boundary is its upper limit (Sastry et al., 1972). Dinosaurs have been described from other exposures of the Kallamedu (Matley, 1929; Yadagiri and Ayyasami, 1987). The Kurmademys locality is a small pocket of fine-grained sandstone and clay, about 6 in. thick. It also contained crocodiles, gar scales, and freshwater gastropods and bivalves and is interpreted as a freshwater pond deposit (Gaffney, Chatterjee, and Rudra, 2001).</p> <p>DEPOSITIONAL ENVIRONMENT: Interpreted as a freshwater pond deposit (Gaffney, Chatterjee, and Rudra, 2001).</p> <p>DIAGNOSIS: As for genus.</p> <p>ETYMOLOGY: For the Kallamedu Formation.</p> <p>REFERRED MATERIAL: ISI R155A, partial skull (fig. 60C); ISI R155B, partial skull (fig. 58C); ISI R155C, partial skull; ISI R158, partial skull (fig. 58A); ISI R159, partial skull (fig. 60A); ISI R155D, lower jaws; ISI R155E, lower jaws (fig. 233); ISI R155F, right ramus; ISI R152, 20 shell elements; ISI R153, 8 shell elements; ISI R157, 74 shell elements; ISI R278, partial shell (figs. 255, 256). See specimen list in Shell Description section for individual shell elements.</p> <p>Sankuchemys Gaffney, Sahni, Schleich,</p> <p>Singh, and Srivastava, 2003</p> <p>TYPE AND ONLY INCLUDED SPECIES: Sankuchemys sethnai Gaffney, Sahni, Schleich, Singh, and Srivastava, 2003.</p> <p>DISTRIBUTION: Maastrichtian of Bombay, India.</p> <p>ETYMOLOGY: Sankuch, ‘‘compressed’’ in Sanskrit, in allusion to the truck that ran over the type specimen.</p> <p>REVISED DIAGNOSIS: Bothremydid of the tribe Kurmademydini with extensive temporal emargination also seen in Kurmademys, but absent in all other Bothremydidae; differing from Kurmademys in having a narrow triturating surface with an accessory ridge parallel to the labial ridge (unique among Bothremydidae except for some Foxemys); foramen posterius canalis carotici interni formed by basisphenoid and pterygoid; foramen stapedio-temporale not visible in dorsal view, as in all other bothremydids except Kurmademys.</p> <p>DISCUSSION: Although many characters are visible in the type skull of Sankuchemys, one important area completely wrecked in SDS/VPL 1125 is the cavum tympani. This region has many characters important in bothremydid systematics that are not determinable for this taxon. The occiput is also reduced to two dimensions, completely obscuring foramina and features in that area. Nonetheless, SDS/VPL 1125 does have enough characters to show its distinctness from all other taxa and to test its relationships. Table 6 compares it with Kurmademys.</p> <p>‘‘ Carteremys ’’ leithii is also from the Intertrappean beds in Mumbai; although its age is unclear, it could be Cretaceous or Paleogene. This taxon, originally consisting of shells and skull material apparently unavailable for 150 years and presumably lost, is considered a nomen dubium (see below). The similarity of age and locality between Sankuchemys and ‘‘ Carteremys ’’ suggests that the two may be the same taxon. However, the ‘‘ Carteremys ’’ figures seem to show a broad rather than a narrow skull, suggesting that they are not the same taxon. In any case, there is no material available for this taxon.</p> <p>Sankuchemys sethnai Gaffney, Sahni,</p> <p>Schleich, Singh, and Srivastava, 2003</p> <p>TYPE SPECIMEN: SDS /VPL 1125, a complete skull (figs. 66, 67) completely smashed flat.</p> <p>TYPE LOCALITY: Amboli Quarry, Jogeshwari, Mumbai, India (map and faunal discussion in Singh et al., 1998) (fig. 12).</p> <p>HORIZON: Green tuff bed of Amboli, Intertrappean beds, late Maastrichtian (discussion in Singh et al., 1998).</p> <p>DIAGNOSIS: As for genus.</p> <p>DEPOSITIONAL ENVIRONMENT: Presumed to be fresh water (Singh et al., 1998).</p> <p>ETYMOLOGY: ‘‘In honor of the discoverer of the holotype skull, Prof. S. F. Sethna, known for his pioneering work on the geology of the Mumbai region’’ (Gaffney, Sahni, Schleich, Singh, and Srivastava, 2003:3).</p> <p>DISCUSSION: See above.</p> <p>SUBFAMILY BOTHREMYDINAE BAUR, 1891,</p> <p>NEW RANK</p> <p>TYPE GENUS: Bothremys Leidy, 1865.</p> <p>INCLUDED GENERA: Cearachelys Gaffney, Campos, and Hirayama, 2001; Galianemys Gaffney, Tong, and Meylan, 2002; Foxemys Tong, Gaffney, and Buffetaut, 1998; Polysternon Portis, 1882; Elochelys Nopcsa, 1931; Zolhafah Lapparent de Broin and Werner, 1998; Rosasia Carrington da Costa, 1940; Araiochelys, n. gen.; Bothremys Leidy, 1865; Chedighaii, n. gen.; Taphrosphys Cope, 1869a; Labrostochelys, n. gen.; Phosphatochelys Gaffney and Tong, 2003; Ummulisani, n. gen.; Rhothonemys, n. gen.; Azabbaremys Gaffney, Moody, and Walker, 2001; Nigeremys Broin, 1977; Arenila Lapparent de Broin and Werner, 1998.</p> <p>DIAGNOSIS: Bothremydidae with this unique character: foramen stapedio-temporale opens anteriorly not dorsally on otic chamber (possibly present in Sankuchemys); other distinguishing characters are: a relatively large postorbital (except in some Taphrosphyini), in contrast to Kurmademydinae; maxilla-vomer contact present (except in Chedighaii and Azabbaremys), in contrast to Kurmademydinae and Podocnemididae; very small to absent fossa precolumellaris, unique among pleurodires except for some Podocnemididae; condylus mandibularis posterior to or on level of basioccipital-basisphenoid suture, in contrast to all other Eupleurodira (except for Polysternon and some Taphrosphyini); condylus occipitalis formed only by exoccipitals (except in Galianemys), in contrast to all other pleurodires except Pelomedusidae; ventral outline of basisphenoid usually triangular; where known, iliac scar on costals 7, 8, and suprapygal.</p> <p>DISCUSSION: The subfamily Bothremydinae consists of the tribes Cearachelyini, Bothremydini, and Taphrosphyini (figs. 1, 2; table 5). It is relatively well supported in figure 288, with a decay value of 3. The alternate possible relationship of Kurmademydini + Taphrosphyini + Bothremydini is discussed under Kurmademydini.</p> <p>INFRAFAMILY CEARACHELYODDA, NEW</p> <p>TYPE GENUS: Cearachelys Gaffney, Campos, and Hirayama, 2001.</p> <p>INCLUDED GENERA: Cearachelys Gaffney, Campos, and Hirayama, 2001; Galianemys Gaffney, Tong, and Meylan, 2002.</p> <p>DIAGNOSIS: Same as for tribe Cearachelyini.</p> <p>TRIBE CEARACHELYINI, NEW</p> <p>TYPE GENUS: Cearachelys Gaffney, Campos, and Hirayama, 2001.</p> <p>INCLUDED GENERA: Cearachelys Gaffney, Campos, and Hirayama, 2001; Galianemys Gaffney, Tong, and Meylan, 2002.</p> <p>DISTRIBUTION: Early Cretaceous of Brazil and Late Cretaceous of Morocco.</p> <p>DIAGNOSIS: Member of the subfamily Bothremydinae with the following unique characters: jugal nearly or completely retracted from orbital margin; fenestra postotica open and formed as a short slit; foramen jugulare posterius open (also in</p> <p>Foxemys and Polysternon); other differentiating characters are: temporal emargination greater than in Bothremydini and Taphrosphyini but less than in Kurmademydini; fossa precolumellaris absent, in contrast to Kurmademydini; preorbital skull narrow, in contrast to Bothremydini; jugal-quadrate contact absent, in contrast to Taphrosphyini; shelf below cavum tympani absent, in contrast to Bothremydodda; supraoccipital-quadrate contact present; exoccipitals do not completely form neck of condylus occipitalis; foramen stapedio-temporale not visible dorsally; foramen stapedio-temporale and foramen nervi trigemini not very close, in contrast to Bothremydodda; condylus mandibularis anterior to condylus occipitalis but not as anterior as in Kurmademydini; palatine forms greater part of triturating surfaces than it does in Taphrosphyini; triturating surfaces wider than in Taphrosphyini but not as wide as in Bothremydini. Six-sided first neural with short posterolateral sides; four-sided second neural not contacting the first costal; plastron with longer anterior lobe than in other bothremydids; pectoral scale posterior to entoplastron.</p> <p>DISCUSSION: The tribe Cearachelyini unites Cearachelys (Albian, Brazil) and Galianemys (Cenomanian, Morocco) by a number of unreversed characters. The three species included are similar in morphology but distinguishable by a number of characters (table 7), although Galianemys probably has a much larger shell, if the suggested association with AMNH 30550 and 30551 proves to be correct. These two genera, found on either side of the early Atlantic Ocean, seem to be a vicariant pair, divided by the opening of the Atlantic, possibly comparable to the situation for Hamadachelys and Brasilemys, and for Euraxemys and Dirqadim.</p> <p>See table 5 for comparison of Cearachelyini with other tribes, and table 7 for comparison of the members of the Cearachelyini.</p> <p>Cearachelys Gaffney, Campos, and</p> <p>Hirayama, 2001 TYPE AND ONLY INCLUDED SPECIES: Cearachelys placidoi Gaffney, Campos, and Hirayama, 2001.</p> <p>TABLE 7 Genera of Cearachelyini</p> <p>a But</p> <p>thinner than in G. emringeri.</p> <p>DISTRIBUTION: Albian of Brazil.</p> <p>ETYMOLOGY: In allusion to the type locality that is in Ceará State, Brazil, and to chelys, turtle in Greek.</p> <p>REVISED DIAGNOSIS: Bothremydid pleurodire of the tribe Cearachelyini with the following unique character: jugal nearly or completely retracted from orbital margin but not widely separated from orbit by broad postorbital-maxilla contact, as in Galianemys; other differentiating characters are: incisura columellae auris open not closed, in contrast to Galianemys; fossa pterygoidea present, as in Galianemys emringeri, not absent, as in G. whitei; cheek with slight emargination not straight, as in Galianemys; interorbital distance narrower than in Galianemys; labial ridge thin in contrast to thick in Galianemys; sulcus olfactorius ridge shallower than in Galianemys; antrum postoticum larger than in Galianemys; tuberculum basioccipitale small and blunt not larger and shelflike, as in Galianemys; jugal-palatine contact more extensive than in Galianemys.</p> <p>Carapace moderately domed as in Pelomedusa, oval in outline, with eight neurals completely separating all eight costals, in contrast to at least one pair of costals meeting in midline as in most other bothremydids; second neural does not contact first costals. Plastron with anterior lobe rounded and broader than in other Santana Pelomedusoides; pectoral scales do not extend anteriorly onto entoplastron, but do extend posteriorly onto mesoplastra; mesoplastron small and laterally placed, as in Podocnemis.</p> <p>DISCUSSION: Do the three skulls of Cearachelys (table 8) represent more than one species? It could be argued that the swollen triturating surfaces, jugal depression, pinched snout, deep fossa pterygoidea, and more medial foramen posterius canalis carotici interni sufficiently differentiate BSP 1976 I 160 from THUg 1798 to make them separate taxa. However, we interpret these differences as individual variation, possibly growth related, and recognize the three skulls as belonging to one species, Cearachelys placidoi.</p> <p>Among recent taxa, intraspecific variation, including maxillary swelling and snout pinching, has been reported in emydids, trionychids, and chelids (Cann, 1998; Carr, 1952; Dalrymple, 1977; Lindeman, 2000). Maxillary swellings typically occur in larger indi-</p> <p>TABLE 8 Comparison of Cearachelys placidoi Specimens viduals and have been associated (sometimes ambiguously) with age, sex, and dietary differences. Similarly, muscle attachment sites can be exaggerated in any vertebrate, and some individuals show greater ridging, thicker or thinner bone, and deeper concavities. The three Cearachelys skulls show a size progression (table 8). If BSP 1976 I 160 is placed at 100 %, then MPSC is 88 % of BSP 1976 I 160 and THUg 1798 is 73 % of BSP 1976 I 160. This suggests an age correlation with BSP 1976 I 160 as oldest, but it may also be due to gender, as in some living emydids (Carr, 1952; Dalrymple, 1977; Lindeman, 2000). Nonetheless, the three Cearachelys skulls form a series showing degrees of variation that we interpret as representing a single species.</p> <p>The swollen maxilla, triturating surface depression, and pinched snout occur in other taxa, but the difference in position of the foramen posterius canalis carotici interni does not occur outside the Bothremydidae. To a certain extent, this may be due to the unusual juxtaposition of a thin-walled canalis caroticus internus within a muscle attachment depression. As described in the Cranial Morphology section (Cearachelys, Pterygoid), an older or larger individual often has better defined muscle attachments, and it is likely that the difference in foramen position is related to the increase in depth of the fossa pterygoidea. At present, it seems best to include all the Cearachelys skulls in the same taxon and to interpret their differences as intraspecific variation.</p> </div>	https://treatment.plazi.org/id/4E7B8791CF44FF8DFD63FD1E17658ECA	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	GAFFNEY, EUGENE S;TONG, HAIYAN;MEYLAN, PETER A	GAFFNEY, EUGENE S, TONG, HAIYAN, MEYLAN, PETER A (2006): EVOLUTION OF THE SIDE-NECKED TURTLES: THE FAMILIES BOTHREMYDIDAE, EURAXEMYDIDAE, AND ARARIPEMYDIDAE. Bulletin of the American Museum of Natural History 300 (300): 1-698, DOI: 10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2, URL: http://dx.doi.org/10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2
4E7B8791CF0DFFD3FD7FFB14175B8E68.text	4E7B8791CF0DFFD3FD7FFB14175B8E68.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Podocnemis congolensis Dollo 1912	<div><p>Podocnemis congolensis Dollo, 1912. Podocnemis congolensis Dollo, 1913. Bantuchelys congolensis Dollo, 1924.</p> <p>TYPE SPECIMEN: Uncataloged specimen in the MRAC, consisting of the first right costal, peripherals 2–4, and fragments of peripheral 1 and the nuchal, figured in Wood (1975: fig. 1) and Dollo (1913: pl. 7, figs. 1, 2). As discussed by Wood (1975), Dollo (1924) designated a new type for Bantuchelys congolensis, but this is preceded by the Dollo (1913) specimen.</p> <p>TYPE LOCALITY: Presumably (Dollo, 1913; Wood, 1975) cliff exposures near Landana, Cabinda, a formerly Portuguese colony on the north side of the Congo River (fig. 14).</p> <p>HORIZON: Presumed to be the sequence consisting of mostly Paleocene sediments (Dollo, 1913; Wood, 1975). Darteville and Casier (1943, 1959) described 32 beds at Landana, the lower 29 as Paleocene with turtles commonly found in most of them. Most of the turtles come from beds identified as Montian in age (Darteville and Casier, 1959; Wood, 1973, 1975).</p> <p>DEPOSITIONAL ENVIRONMENT: The Taphrosphys congolensis material is thought to have come mostly from near-shore marine beds (Cahen, 1954) and is associated with rarer cheloniid specimens (Wood, 1973) and crocodiles (Dollo, 1914). The fish from these units have been described by Darteville and Casier (1943, 1949, 1959).</p> <p>DIAGNOSIS: A bothremydid pleurodire of the genus Taphrosphys with these unique characters: premaxilla labial ridge deep not shallow; prefrontal thin and short; distinguished from the other two species as follows: from T. sulcatus: rostrum basisphenoidale a long and prominent, laterally compressed rod; sella turcica deep and narrow; dorsum sellae high; processus clinoideus high and large; processus inferior parietalis closer to midline than in T. sulcatus; from T. ippolitoi: snout not expanded; quadrate shelf not expanded laterally; sulcus eustachii opens ventrally rather than posteroventrally; fossa precolumellaris absent; sulcus eustachii without lateral process; premaxilla narrow; fenestra postotica not subdivided; tuberculum basioccipitale smaller; lateral surface of maxilla convex rather than concave; cavum tympani shallow rather than deep.</p> <p>ETYMOLOGY: Presumably in allusion to the Congo River, adjacent to the type locality.</p> <p>REFERRED MATERIAL: Uncataloged skull (figs. 187–189) in the MRAC collections, ‘‘Landana’’ presumably Paleocene. Although there is a report (Wood, personal commun.) that shell material was found with this skull, we have not seen it. The identification of this skull with the type shell material is based only on their common occurrence at the same locality.</p> <p>The following specimens described in Wood (1975), all from the Montian Paleocene, Landana cliffs, Cabinda: Uncataloged MRAC: an eighth cervical vertebra, parts of the carapace including the nuchal, first and second neurals, the pygal, the first and fifth pleurals, and various peripherals (first through third, eighth, ninth, and eleventh) and a pelvis (Wood, 1975: pl. 6; all listed, without numbers, in Dollo, 1924); MRAC 3086A, two adjacent peripherals; MRAC 4794 (Wood, 1975: pls. 3, 4), a nearly complete plastron lacking the right xiphi- and hypoplastron, the lateral portion of the right hyoplastron, and medial parts of the left hypo- and hyoplastron; MRAC 4795 (Wood, 1975: pls. 1, 2), the posterior third of a carapace; MRAC 6316, fragment of a peripheral; MRAC 6320 (Wood, 1975: pl. 6), posterior portion of a pair of xiphiplastra with associated left pelvis; MRAC 6322, nearly complete left xiphiplastron; MRAC 6323, fragment of a right xiphiplastron; MRAC 6328, fragment of the proximal end of a pleural; MRAC 6329, fragment of a peripheral; MRAC 6337 (Wood, 1975: pl. 6), complete pair of xiphiplastra; and MRAC 6340, fragment of a peripheral. Wood (1975) also referred the following undeterminable shell fragments to this species on the basis of their size and surface texture: MRAC 6295, 6313–6315, 6317, 6319, 6321, 6324–6326, 6331–6335, 6338, 6339, 6341– 6344, 16024, and 16025.</p> <p>MRAC 3090, lower jaw (fig. 250; Dollo, 1924: fig. 1; Wood, 1973: pl. 3), bed 12, Landana, Cabinda (Wood, 1973), originally identified as Bantuchelys congolensis by Dollo (1924), then redescribed as a lophochelyine toxochelyid by Wood (1973). However, in light of the narrow triturating surfaces of the lower jaw in the only other Taphrosphyini known with a jaw, Rhothonemys; we think that there is a good basis for identifying MRAC 3090 as Taphrosphys congolensis (see below).</p> <p>PREVIOUS WORK: First named Podocnemis congolensis by Dollo in 1912, without a specimen or diagnosis. The actual description dates from Dollo (1913), the first time the name was used legally (Wood, 1975). Dollo (1913) provided figures of shell pieces and a rudimentary description. Dollo was correct in relating the form to Podocnemis - like Pelomedusoides, but he apparently did it on the basis of an axillary musk duct, a character also found in cryptodires. Dollo (1924) identified a lower jaw as belonging to his new genus Bantuchelys, which he created for congolensis. Wood (1973) identified the lower jaw as a toxochelyid (which we do not agree). Wood (1975) considerably increased knowledge of congolensis by describing the plastron, much of the carapace, and reassigning the species to Taphrosphys on the basis of plastral morphology (with which we agree).</p> <p>DISCUSSION: The skull identified here as Taphrosphys congolensis (MRAC uncataloged) was originally associated with a shell fragment (Wood, personal commun.) having the typical Taphrosphys surface texture. The skull is clearly very similar to skulls of Taphrosphys sulcatus, and the most common shells in the Landana sequence are very similar to Taphrosphys sulcatus, which is the basis for the identification.</p> <p>The lower jaw described by Dollo (1924) as the pleurodire ‘‘ Bantuchelys congolensis ’’ and by Wood (1973) as a possible toxochelyid is probably the lower jaw of Taphrosphys congolensis. We agree with Dollo’s identification and corroborate it with new evidence. The association of the jaw in the same beds as the skull and shell of Taphrosphys congolensis supports this idea as argued by Dollo (1924), but as Wood (1973) demonstrated, there are also sea turtles in these units. The discovery of a lower jaw of a closely related member of the tribe Taphrosphyini, the Moroccan Rhothonemys brinkmani, adds new support to Dollo’s contention. The very narrow lower jaw, MRAC 3090, inconsistent with African pleurodires then known to Wood (1973), was a reason for Wood to reject Dollo’s assertion. The discovery of the Rhothonemys lower jaw, however, shows that at least one Taphrosphyini also has very narrow lower jaws. Furthermore, MRAC 3090 has a large processus retroarticularis, absent in chelonioids. We have not directly examined MRAC 3090 and cannot present a detailed description of it, but based on figures in Dollo (1924) and Wood (1973) (reproduced here as fig. 250) we can list the following similarities between these specimens: very narrow triturating surface; narrow jaw rami; symphyseal hook; processus retroarticularis present; and V-shaped sulcus cartilaginis meckelii. These similarities are consistent with MRAC 3090 being identified as a Taphrosphyini, but they are not conclusive. We think that Dollo’s original identification is well enough supported to include this jaw in the dataset for the few characters that it provides. Exclusion of it does not alter the MPC.</p> <p>Another lower jaw that may belong to the tribe Taphrosphyini was described by Bardet et al. (2000: 281, fig.7d, e) as a ‘‘Chelonioidea gen. and sp. indet.’’ Associated with this jaw are shell elements also described and figured (Bardet et al., 2000: 281, fig.7a–c, g), one of which (fig. 7a) has the iliac scar small, round, and at the shell margin, features probably diagnostic for the tribe Taphrosphyini. The lower jaw is very similar to those of Rhothonemys and Taphrosphys congolensis (see figs. 248–250).</p> <p>See table 17 for a comparison of the species in Taphrosphys.</p> <p>Labrostochelys, new genus</p> <p>TYPE AND ONLY INCLUDED SPECIES: Labrostochelys galkini, n. gen. et sp.</p> <p>DISTRIBUTION: Paleocene of Morocco.</p> <p>ETYMOLOGY: Labrostos, Greek for rushing furiously, in allusion to its sharply pointed head.</p> <p>DIAGNOSIS: A bothremydid pleurodire of the tribe Taphrosphyini with these unique characters among Taphrosphyini: skull very long and narrow with an elongate, tapering preorbital region; extremely long prefrontal, maxilla, and premaxilla; premaxilla with anterior projection extending anterior to labial ridge unique among turtles; apertura narium externa partially or completely divided by prefrontal and premaxilla; long squamosal projection extending posteriorly to an extent unique among turtles (except for some trionychoids); large, triangular basisphenoid nearly separating pterygoids; interorbital distance relatively shorter than in any other Taphrosphyini; fenestra postotica more horizontal than in other Taphrosphyini; processus trochlearis pterygoidei parasagittal and very small; other differentiating characters are: narrow jugal, in contrast to Azabbaremys and Phosphatochelys; squamosal with vertical flange, as in Taphrosphys and Phosphatochelys and in contrast to Azabbaremys; triturating surface a broadly curved trough, as in Taphrosphys and in contrast to all other Taphrosphyini; labial ridge on maxilla thin, as in Taphrosphys and in contrast to all other Taphrosphyini; sulcus eustachii with dorsal process; foramen posterius canalis carotici interni formed almost completely by quadrate with small contribution of pterygoid; posteroventrally opening pocket on posterior surface of quadrate, as in Taphrosphys; postorbital with medial process; sulcus palatinopterygoideus wide; ventrally opening channel at back of skull, as in Taphrosphys; condylus mandibularis well anterior to condylus occipitalis, as in Taphrosphys; fossa pterygoidea absent.</p> <p>DISCUSSION: See table 16 for a comparison of the genera in the tribe Taphrosphyini.</p> <p>Labrostochelys galkini, new species</p> <p>TYPE SPECIMEN: AMNH 30043, a nearly complete skull (figs. 192, 193, 195, 287) purchased from M. Hammer, 1998.</p> <p>TYPE LOCALITY: Phosphates near Oued Zem, Ouled Abdoun Basin, Morocco (figs. 14–16).</p> <p>HORIZON: Presumed to be Tertiary based on matrix.</p> <p>DEPOSITIONAL ENVIRONMENT: Near-shore marine; discussion of Moroccan phosphate deposits is under Araiochelys hirayamai.</p> <p>DIAGNOSIS: As for genus.</p> <p>ETYMOLOGY: For Judy Galkin, in appreciation of her years of efforts in the Department of Vertebrate Paleontology, AMNH, on behalf of this project.</p> <p>REFERRED MATERIAL: AMNH 29984, a nearly complete skull (fig. 194), Danian based on shark teeth in matrix (Cappetta, personal commun.), near Khouribga, Ouled Abdoun Basin, Morocco, donated by H. Galiano, 1995.</p> <p>PREVIOUS WORK: None.</p> <p>DISCUSSION: This very narrow-jawed turtle differs considerably from the other bothremydids, resembling trionychids instead. It illustrates the remarkable degree of diversity present in the pleurodires, particularly in the near-shore seas of the African margin. This unusual species is known from two skulls, collapsed dorsoventrally but relatively well preserved. Labrostochelys is the sister taxon to Taphrosphys, Rhothonemys, Ummulisani, and Phosphatochelys (fig. 288).</p> <p>Phosphatochelys Gaffney and Tong, 2003</p> <p>TYPE AND ONLY INCLUDED SPECIES: Phosphatochelys tedfordi Gaffney and Tong, 2003.</p> <p>DISTRIBUTION: Eocene of Morocco.</p> <p>ETYMOLOGY: In allusion to its discovery in the phosphate beds of Morocco.</p> <p>REVISED DIAGNOSIS: A bothremydid pleurodire of the tribe Taphrosphyini with these unique characters among Taphrosphyini: preorbital region very short with extremely narrow dorsal process of maxilla; wide figure 8-shaped apertura narium externa lying above a premaxilla that slopes posterodorsally to anteroventrally; frontal small and widely separated from orbital margin; broad prefrontal-parietal contact; large quadrate extending anteriorly to cover half of cheek; labial ridge of maxilla deeper than in other Taphrosphyini except Rhothonemys; quadratojugal widely separated from jugal, as in Rhothonemys; anterolaterally facing trough developed on pterygoid, parietal, and quadrate extending anterodorsally from foramen nervi trigemini ventrolaterally to condylus mandibularis. Other differentiating characters are: squamosal with vertical flange in contrast to Azabbaremys; palate dorsally arched, in contrast to Taphrosphys and Labrostochelys; sulcus eustachii with dorsal process, in contrast to Azabbaremys and Labrostochelys; foramen posterius canalis carotici interni formed by pterygoid and quadrate; postorbital lacks medial process and postorbital wall open, in contrast to Arenila and Nigeremys; condylus mandibularis anterior to condylus occipitalis; fossa pterygoidea absent.</p> <p>DISCUSSION: See table 16 for a comparison of the genera in the tribe Taphrosphyini.</p> <p>Phosphatochelys tedfordi Gaffney and Tong, 2003</p> <p>TYPE SPECIMEN: AMNH 30008, complete skull without lower jaws (figs. 198, 199, 203, 279A, 286), gift from François Escuillie´.</p> <p>TYPE LOCALITY: Oued Zem, Ouled Abdoun Basin, Morocco (Gaffney and Tong, 2003) (figs. 14–16).</p> <p>HORIZON: Ypresian phosphates, Eocene, based on shark teeth in matrix (Cappetta, personal commun.) (fig. 17; see Araiochelys</p> <p>TABLE 18</p> <p>Comparisons of Two Specimens of Phosphatochelys tedfordi hirayamai for discussion of Moroccan phosphates; see also table 11). The original description of AMNH 30008 stated that it was Paleocene based on shark teeth analysis. Further study of the shark teeth has shown this to be in error and that the age, again based on shark teeth (Cappetta, personal commun.), is Eocene.</p> <p>DEPOSITIONAL ENVIRONMENT: Near-shore marine; discussion of Moroccan phosphate deposits is under Araiochelys hirayamai.</p> <p>DIAGNOSIS: As for genus.</p> <p>ETYMOLOGY: For Dr. Richard H. Tedford, in recognition of his lifelong contributions to vertebrate paleontology in general and to the American Museum of Natural History in particular.</p> <p>REFERRED MATERIAL: MDEt 26, a nearly complete skull (figs. 200, 201), Ypresian phosphates, based on shark teeth (Cappetta, personal commun.), Ouled Abdoun Basin, Morocco.</p> <p>PREVIOUS WORK: The species was named and described by Gaffney and Tong (2003). All the figures from that paper, plus new ones, are repeated here. The description and diagnosis have also been revised and updated with the addition of new taxa.</p> <p>DISCUSSION: It is possible that the two skulls now known for Phosphatochelys represent two species. A list of differentiating characters is in table 18 and features are discussed in the descriptive section. However, in the absence of more material and the probability that at least some of these features are individual variation, we have shown restraint and not created a second species.</p> <p>Ummulisani, new genus</p> <p>TYPE AND ONLY INCLUDED SPECIES: Ummulisani rutgersensis, n. gen. et sp.</p> <p>DISTRIBUTION: Eocene of Morocco.</p> <p>ETYMOLOGY: Ummu-‘lIhsan, Arabic, ‘‘mother of integrity’’. The senior author is very much indebted to Mark Stephen Caponigro of Columbia University for suggesting this name.</p> <p>DIAGNOSIS: A member of the tribe Taphrosphyini with the unique feature of a hornlike, anterodorsal process on each prefrontal. Other distinguishing features are septum orbitotemporale open and reduced to low ridge on postorbital and parietal, as in Phosphatochelys, Taphrosphys, and Azabbaremys, but in contrast to Nigeremys and Arenila; apertura narium externa smaller than in Rhothonemys, but similar in size to Phosphatochelys; preorbital part of skull short, in contrast to Taphrosphys and Labrostochelys; triturating surface unique in having very deep labial ridge beneath orbit with very low to absent labial ridge beneath apertura narium externa; labial ridge and maxilla very thin, as in Labrostochelys and in contrast to Phosphatochelys and Rhothonemys; wide quadrate-basisphenoid contact, as in Taphrosphys and in contrast to all other Taphrosphyini; foramen posterius canalis carotici interni formed entirely by quadrate, as in Labrostochelys, but in contrast to all other pleurodires.</p> <p>DISCUSSION: This genus, now known from three skulls, one with a plastron, is one of the more unusual pleurodires. Ummulisani has small hornlike processes on the prefrontals, and these may have borne a scale that would make the process larger in life, as in the squamosal horns of meiolaniids. This is clear evidence for intense mating battles and burrowing. The phylogenetic analysis resolves Ummulisani as the sister taxon to Phosphatochelys.</p> <p>See table 16 for a comparison of the genera in the tribe Taphrosphyini.</p> <p>Ummulisani rutgersensis, new species</p> <p>TYPE SPECIMEN: AMNH 30563, skull, lacking palate (figs. 206, 207), purchased from Adam Aaronson.</p> <p>TYPE LOCALITY: ‘‘Mrah Iaresh, 20 km south east of Ouled Boali’’ (from Adam Aaronson), Morocco (figs. 14–16).</p> <p>HORIZON: ‘‘Eocene Phosphates, Upper Ypresian, Couche O’’ (from Adam Aaronson); see figure 17 and Araiochelys hirayamai for discussion of Moroccan phosphates (see table 11).</p> <p>DEPOSITIONAL ENVIRONMENT: Near-shore marine (see Araiochelys hirayamai for discussion of Moroccan phosphates).</p> <p>DIAGNOSIS: As for genus.</p> <p>ETYMOLOGY: For Rutgers, the State University of New Jersey, in gratitude to the faculty of the Department of Geology, Rutgers College, New Brunswick, who from 1961 to 1965 provided the senior author with inspiration, encouragement, and friendship, as well as with an education.</p> <p>REFERRED MATERIAL: AMNH 30562, skull and plastron (figs. 268, 269), Paleogene phosphates, Mrah Iahresh, Morocco; AMNH 30569, skull, Ypresian (based on shark teeth; Cappetta, personal commun.), phosphates, Oued Zem, Ouled Abdoun Basin, Morocco.</p> <p>PREVIOUS WORK: None.</p> <p>DISCUSSION: See above.</p> <p>Rhothonemys, new genus</p> <p>TYPE AND ONLY INCLUDED SPECIES: Rhothonemys brinkmani, n. gen. et sp.</p> <p>DISTRIBUTION: Paleogene of Morocco.</p> <p>ETYMOLOGY: Rhothon, Greek for nose, beak, in allusion to the gigantic apertura narium externa.</p> <p>DIAGNOSIS: A bothremydid pleurodire of the tribe Taphrosphyini with these unique characters among Taphrosphyini: apertura narium externa larger than in any other bothremydid; maxilla deeper and longer than in any other bothremydid; anterior half of skull deeper with respect to rest of skull than in any other bothremydid; labial ridge thick in cross section with broadly curved outer surface and slightly concave inner surface. Other differentiating features are: parietal enters orbital margin, in contrast to all bothremydids except Phosphatochelys and Ummulisani; squamosal with vertical flange, in contrast to Azabbaremys; frontal shorter than prefrontal (also in Phosphatochelys), enters orbit for its full length; interorbital width narrower than in other Taphrosphyini except in Labrostochelys; parietal forms major part of postorbital ridge and pocket, as in Taphrosphys and Phosphatochelys.</p> <p>DISCUSSION: See table 16 for a comparison of the genera in the tribe Taphrosphyini.</p> <p>Rhothonemys brinkmani, new species</p> <p>TYPE SPECIMEN: AMNH 30521 (figs. 209–211), partial skull, lacking palate and basicranium, and lower jaw.</p> <p>TYPE LOCALITY: Ouled Abdoun Basin, Morocco, based on matrix composition and included fossils.</p> <p>HORIZON: Within the Paleogene phosphate sequence, based on matrix composition and included fossils (see table 11).</p> <p>DEPOSITIONAL ENVIRONMENT: Near-shore marine: discussion of Moroccan phosphate deposits is under Araiochelys hirayamai.</p> <p>DIAGNOSIS: As for genus.</p> <p>ETYMOLOGY: In recognition of the contributions of Dr. Donald Brinkman, Royal Tyrrell Museum of Palaeontology, to the field of chelonian paleontology and evolution.</p> <p>REFERRED MATERIAL: None.</p> <p>PREVIOUS WORK: None.</p> <p>DISCUSSION: Although the only known specimen of this taxon is an incomplete skull, lacking most of the palate and basicranium, the preserved areas are so different from other pleurodires that it is easily diagnosed. There are also sufficient characters to resolve it in the cladogram (fig. 288) as the sister taxon to Phosphatochelys + Ummulisani.</p> <p>Azabbaremys Gaffney, Moody, and Walker, 2001</p> <p>TYPE AND ONLY INCLUDED SPECIES: Azabbaremys moragjonesi Gaffney, Moody, and Walker, 2001.</p> <p>DISTRIBUTION: Paleocene of eastern Mali. ETYMOLOGY: Azabbar, a monster in popular Mali folk stories in the Tamasheq language. Thanks to Mr. Ibrahim Litny for suggesting this reference.</p> <p>REVISED DIAGNOSIS: A bothremydid pleurodire of the tribe Taphrosphyini with these unique characters among Taphrosphyini: triturating surfaces covered with prominent toothlike crenellations forming a corrugated surface; prefrontal extending anteriorly to anterior edge of premaxilla; deep premaxilla with anterior surface sloping anterodorsal to posteroventral; skull roof broadly convex to a greater degree than in any other Taphrosphyini. Other differentiating characters are: short, wedge-shaped skull higher than in Arenila and Nigeremys, differing from the short skull of Phosphatochelys by the presence of a prominent skull roof convexity; broad jugal exposure in orbit, as in Phosphatochelys and Arenila but in contrast to Taphrosphys and Labrostochelys; squamosal without vertical flange in contrast to Taphrosphys, Labrostochelys, and Phosphatochelys; labial ridge thicker than in Taphrosphys and Labrostochelys but thinner than in Arenila and Nigeremys; no maxilla-vomer contact; dorsally arched palate in contrast to Taphrosphys and Labrostochelys; foramen posterius canalis carotici interni formed by pterygoid and quadrate; postorbital lacking medial process; sulcus palatinopterygoideus wide; vomer narrow; condylus mandibularis anterior to condylus occipitalis; basisphenoid solid triangular not excavated posteriorly; postorbital wall open; fossa pterygoidea absent.</p> <p>PREVIOUS WORK: See species for Previous Work.</p> <p>DISCUSSION: See table 16 for a comparison of the genera in the tribe Taphrosphyini.</p> <p>Azabbaremys moragjonesi Gaffney, Moody, and Walker, 2001</p> <p>TYPE SPECIMEN: BMNH R 16370, a complete skull lacking lower jaws (figs. 214–218, 280, 281C, 286A).</p> <p>TYPE LOCALITY: North of In Fargas near Samit, eastern Mali (see Moody and Sutcliffe, 1990, 1991, 1993).</p> <p>HORIZON: Teberemt Formation, Paleocene (see Moody and Sutcliffe, 1990, 1991, 1993, 1995).</p> <p>DEPOSITIONAL ENVIRONMENT: Shallow marine (Moody and Sutcliffe, 1993).</p> <p>DIAGNOSIS: As for genus.</p> <p>ETYMOLOGY: For Ms. Morag Jones, a student who participated in the discovery of this specimen; she died tragically on the first Mali expedition (Gaffney, Moody, and Walker, 2001).</p> <p>REFERRED MATERIAL: None.</p> <p>PREVIOUS WORK: This taxon was named and described by Gaffney, Moody, and Walker (2001); the diagnosis and description is updated and revised here.</p> <p>DISCUSSION: Azabbaremys is the sister taxon to another Mali form, the undescribed CNRST-SUNY 199. Together they are weakly supported as the sister group to the remaining Taphrosphyina.</p> <p>UNDESCRIBED TAXON: CNRST SUNY 199</p> <p>SPECIMEN: CNRST SUNY 199, a nearly complete skull, figured in Gaffney, Roberts, Sissoko, Boure´, Tapanila, and O’Leary (in press).</p> <p>LOCALITY: South of the Adrar des Iforas Mountains, between Saguirilidad and In Fargas, Mali.</p> <p>HORIZON: Middle to upper portion of the Paleocene Teberemt Formation.</p> <p>DEPOSITIONAL ENVIRONMENT: Near shore marine.</p> <p>REVISED DIAGNOSIS: A bothremydid pleurodire of the subtribe Taphrosphydina with these unique characters among the tribe Taphrosphyini: small pit formed by jugal, maxilla, and palatine on triturating surface; jugal exposed on triturating surface; accessory ridge present on anterior triturating surface; wide palatine-basisphenoid contact separating pterygoids on midline; supraoccipital-quadrate contact present; basioccipital narrowly enters condylus occipitalis; palatine-jugal contact in small septum orbitotemporale; other distinguishing characters: skull relatively long and narrow in contrast to all Taphrosphyini except Labrostochelys; fossa pterygoideus deep and narrow as in Nigeremydina but in contrast to all other Taphrosphydina; foramen posterius canalis carotici interni formed by pterygoid, basisphenoid, and quadrate in contrast to all Taphrosphyini except Taphrosphys; small remnant of septum orbitotemporale present consisting of ventral parietal process as in Phosphatochelys but in contrast to other Taphrosphyini.</p> <p>TABLE 19</p> <p>Comparison of Arenila and Nigeremys</p> <p>REFERRED MATERIAL: None.</p> <p>PREVIOUS WORK: Possibly Gaffney, Roberts, Sissoko, Boure´, Tapanila, and O’Leary (in press), if it is published before the present work.</p> <p>DISCUSSION: This skull is named and described in a paper that will have a publication date close to the publication date of the present paper, that is, it may be published before or after the present paper. The actual dates of publication are not under the control of the authors. Therefore, we are not mentioning the name of this new taxon here, it is referred to only by its catalogue number, CNRST SUNY 199. Although the description and figures of this skull appear in Gaffney, Roberts, Sissoko, Boure´, Tapanila, and O’Leary (in press), the taxon has been entered into the data set analysed here. The taxon appears as CNRST SUNY 199 in the cladograms in figures 288– 292, 294, 296–314, 317.</p> <p>SUBTRIBE NIGEREMYDINA, NEW</p> <p>TYPE GENUS: Nigeremys Broin, 1977.</p> <p>INCLUDED GENERA: Nigeremys Broin, 1977; Arenila Lapparent de Broin and Werner, 1998.</p> <p>DIAGNOSIS: Member of tribe Taphrosphyini with the following characters contrasting with subtribe Taphrosphyina: labial ridge thicker; septum orbitotemporale completely closed; antrum postoticum completely closed (also in Azabbaremys and Ummulisani); condylus mandibularis posterior to condylus occipitalis; fossa pterygoidea deep and narrow (also in CNRST SUNY 199); basisphenoid ventral outline V-shaped.</p> <p>DISCUSSION: See table 19 for a comaparison of the genera in the Nigeremydina.</p> </div>	https://treatment.plazi.org/id/4E7B8791CF0DFFD3FD7FFB14175B8E68	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	GAFFNEY, EUGENE S;TONG, HAIYAN;MEYLAN, PETER A	GAFFNEY, EUGENE S, TONG, HAIYAN, MEYLAN, PETER A (2006): EVOLUTION OF THE SIDE-NECKED TURTLES: THE FAMILIES BOTHREMYDIDAE, EURAXEMYDIDAE, AND ARARIPEMYDIDAE. Bulletin of the American Museum of Natural History 300 (300): 1-698, DOI: 10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2, URL: http://dx.doi.org/10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2
4E7B8791CF06FFD6FF9FF95A1647896B.text	4E7B8791CF06FFD6FF9FF95A1647896B.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Potamochelys Bergounioux and Crouzel 1968	<div><p>Potamochelys Bergounioux and Crouzel, 1968.</p> <p>TYPE AND ONLY INCLUDED SPECIES: Potamochelys gigantea Bergounioux and Crouzel, 1968.</p> <p>DISTRIBUTION: Maastrichtian of Niger,?Eocene of Mali.</p> <p>ETYMOLOGY: Presumably in allusion to the country of Niger.</p> <p>REVISED DIAGNOSIS: A bothremydid pleurodire of the subtribe Nigeremydina; differs from Arenila in these characters: smaller orbits; suborbital maxillary plate deeper; labial ridge blunt.</p> <p>PREVIOUS WORK: See species Previous Work.</p> <p>DISCUSSION: See table 16 for a comparison of the genera in the tribe Taphrosphyini.</p> <p>Nigeremys gigantea (Bergounioux and</p> <p>Crouzel, 1968)</p> <p>TYPE SPECIMEN: MNHN (P) NIR 1 (label), a nearly complete skull (figs. 221– 223) lacking lower jaws with its surface badly eroded. However, Bergounioux and Crouzel (1968: 183) gave its number as ‘‘Muséum de Paris … 1964-27’’.</p> <p>TYPE LOCALITY: ‘‘Niger’’ (Bergounioux and Crouzel, 1968: 179). ‘‘East of Ibeceten, Niger’’ (Lapparent de Broin and Werner, 1998: 145) (fig. 14).</p> <p>HORIZON: ‘‘Maastrichtian’’ (Bergounioux and Crouzel, 1968: 183).</p> <p>DEPOSITIONAL ENVIRONMENT: Specimen found with: ‘‘ Mosasaurus nigeriensis Swinton, Stratodus apcalis Cope, Onchosaurus pharao Dames …’’ (Bergounioux and Crouzel, 1968: 183), suggesting a near-shore marine burial environment.</p> <p>DIAGNOSIS: As for genus.</p> <p>ETYMOLOGY: Unknown, presumably referring to the large size of the skull.</p> <p>REFERRED MATERIAL: BMNH R 10927, articulated right and left premaxillae and maxillae, partial quadrate, ‘‘loc 3, In Fargas, Samit limestone’’ (label), Eocene, Mali. The specimen as preserved is almost identical with Nigeremys, but it is too incomplete to be certain, so we extend the range of Nigeremys with doubt.</p> <p>PREVIOUS WORK: Nigeremys Broin, 1977 began life as Potamochelys Bergounioux and Crouzel, 1968. Bergounioux and Crouzel (1968) named what they thought was a new genus for a large, battered skull from Niger. They thought that in the absence of a carapace it was difficult to place their ‘‘ Potamochelys ’’ taxonomically, but they concluded that it was a cryptodire, possibly related to chelydrids. F. M. Bergounioux, a Catholic priest in Lyon, was infamous for his other work on fossil turtles (see section on Dubious Taxa). Bergounioux and Crouzel (1968) gave a brief description with dorsal and ventral photographs of the skull (Bergounioux and Crouzel, 1968: figs. 1, 2) and a dorsal line drawing (fig. 1b). The dorsal line drawing is in error; there are no nasals and we have interpreted other sutures differently, although sutures are very difficult to see on this specimen. Later, Broin (1977: 83) recognized that Potamochelys Bergounioux and Crouzel, 1968 was preoccupied by Potamochelys Fitzinger, 1843 (a synonym of Trionyx according to Romer, 1956: 514), and created the new genus, Nigeremys, for the species gigantea.</p> <p>Bergounioux and Crouzel (1968) had referred their ‘‘ Potamochelys ’’ to the Chelydridae with doubt, and Broin (1977) was the first to recognize its pleurodiran affinities. Antunes and Broin (1988) identified Nigeremys as a bothremydid, but unfortunately allied it with the undiagnosable ‘‘ Sokotochelys ’’ Halstead, 1979b in a ‘‘Groupe Nigeremys ’’, which was in a larger group containing Bothremys and Rosasia, but not Taphrosphys. In the description and discussion sections, there was new information about Nigeremys.</p> <p>Lapparent de Broin and Werner (1998) provided the most complete previous description of Nigeremys. They argued for the close relationship of Arenila with Nigeremys, a conclusion supported by us, and provided a comparative description for the two taxa, line drawings for Nigeremys (fig. 4b, f) and measurements of the type skull, MNHN(P) NIR 1. Lapparent de Broin and Werner (1998) showed the ‘‘phyletic Group Nigeremys ’’ containing Nigeremys, ‘‘ Sokotochelys ’’, and Arenila, along with more fragmentary material.</p> <p>DISCUSSION: Nigeremys is based on a nearly complete, but poorly preserved and badly prepared, skull. Painted sutures and repair materials obscure important areas. Although we disagree with some of the Lapparent de Broin and Werner (1998) sutures, we agree with their conclusion that Nigeremys is closely related to Arenila. In fact, our reconstruction of Arenila shows it to be very similar to Nigeremys. Both could be placed in the same genus as separate species, as they are a strictly monophyletic group, but we keep the genera separate here for old times’ sake.</p> <p>Arenila Lapparent de Broin and Werner, 1998</p> <p>TYPE AND ONLY INCLUDED SPECIES: Arenila krebsi Lapparent de Broin and Werner, 1998.</p> <p>DISTRIBUTION: Late Cretaceous, Egypt.</p> <p>ETYMOLOGY: Arena, Latin for sand (Lapparent de Broin and Werner, 1998).</p> <p>DIAGNOSIS: A bothremydid pleurodire of the subtribe Nigeremydina; differs from Nigeremys in these characters: larger orbits; suborbital maxillary plate shallower; labial ridge acute.</p> <p>DISCUSSION: See table 16 for a comparison of the genera in the tribe Taphrosphyini.</p> <p>Arenila krebsi Lapparent de Broin and</p> <p>Werner, 1998</p> <p>TYPE SPECIMEN: TUB Vb-641, a partial skull (figs. 226–230).</p> <p>TYPE LOCALITY: ‘‘Ammonite Hills, interdunal channel 28, loc. 291080/2’’ (Lapparent de Broin and Werner, 1998: 174) (fig. 14).</p> <p>HORIZON: ‘‘Dakla Formation, Ammonite Hill Member, Maastrichtian’’ (Lapparent de Broin and Werner, 1998: 174).</p> <p>DIAGNOSIS: Same as for genus.</p> <p>ETYMOLOGY: In honor of Dr. Bernard Krebs (Lapparent de Broin and Werner, 1998: 174).</p> <p>REFERRED MATERIAL: Lapparent de Broin and Werner (1998) identified a partial carapace, TUB Vb-648, lacking peripherals, nuchal, and pygal, as ‘‘? cf. Arenila krebsi ’’. The ‘‘cf.’’ is an abbreviation of the Latin, confere, meaning to compare, but there is no shell associated with the type skull to be used for comparison. The reasons for identifying this shell as Arenila are not specifically stated, but it occurs in the same unit as the type skull, is of an appropriate size, and is excluded from their ‘‘ Bothremys Group’’ and ‘‘ Taphrosphys Group’’ by Lapparent de Broin and Werner (1998). It is too incomplete to be included in the dataset presented here, and is considered Pelomedusoides incertae sedis.</p> <p>PREVIOUS WORK: Arenila has been described only in Lapparent de Broin and Werner (1998). The photographs, plates VI and VII (Lapparent de Broin and Werner, 1998), are of good quality but lack line drawings identifying elements, and only partial restorations of the palate and lateral views are shown (Lapparent de Broin and Werner, 1998: fig. 12). Here we provide line drawings for these photographs (figs. 227, 229) as well as new photographs in the same orientation.</p> <p>DISCUSSION: Lapparent de Broin and Werner (1998) identified Arenila as a bothremydid and a member of the ‘‘ Nigeremys Group’’. They identified a separate ‘‘ Taphrosphys Group’’. Here, we argue that Arenila is closely related to Nigeremys and agree with Lapparent de Broin and Werner.</p> <p>Examinations of the type skull and associated material in the Technische Universität Berlin revealed that two skull elements, not identified by Lapparent de Broin and Werner, are part of the type skull, TUB Vb-641. These elements are included in the line drawings. They are: a partial right maxilla, premaxilla, and vomer; and a partial right pterygoid consisting of the processus trochlearis pterygoidei. These elements articulate with the type skull directly, so there is little doubt of the association.</p> <p>Our restoration of the skull of Arenila (fig. 224) differs from that of Lapparent de Broin and Werner (1998: fig. 12) in some details in ventral view and in overall shape in lateral view. These differences result from the newly added elements, different interpretation of some sutures, and a different interpretation of postmortem crushing. Considering the poor state of preservation of the type skull, the new restoration does not differ greatly from the original one.</p> <p>DUBIOUS TAXA</p> <p>A congenital disease of paleontology is the naming of poorly preserved specimens as new taxa. No doubt many of these are actually organic remains, although the published descriptions often do not demonstrate this unequivocally. Nonetheless, many names in the literature are based on inadequate specimens, and much effort is spent repeating them, usually to no positive effect. We have essentially divided the names into those with hope for future workers (incertae sedis) and those without hope of further identifications (nomina dubia). We have chosen these designations, which are commonly used to categorize poorly known taxa. We use ‘‘incertae sedis’’ (5 ‘‘of uncertain position’’) to designate taxa that preserve enough characters to be usefully diagnosed at the alpha level, but do not have enough characters to test their wider relationships at the present time. In our opinion, these taxa are complete enough so that there is hope for future material to be found and indentified with the type specimens. For incertae sedis the degree of uncertainty is always indicated.</p> <p>The incertae sedis designation is not used for taxa that cannot be diagnosed adequately on the basis of the type specimen. Rather, the designation ‘‘nomen dubium’’ is used in the sense of Mayr (1969: 347), ‘‘an available name which cannot be assigned to a definite taxon owing to shortcomings in the original diagnosis or the type material.’’ The decision on what are an adequate diagnosis and type specimen is subjective, but we are of the opinion that a more restricted view serves systematists and other researchers better than a more lax one. Certainly many of these fragmentary specimens may represent unique taxa, but once they are named and become referred to in the literature, they are often used as the basis for studies in biogeography, diversity, and evolution, when the original material is completely inadequate for such work.</p> <p>TAXA INCERTAE SEDIS</p> <p>Apodichelys lucianoi Price, 1954</p> <p>TYPE SPECIMEN: DNPM 418-R, a steinkern.</p> <p>DISCUSSION: This taxon is from the Late Cretaceous Apodi Formation of Rio Grande del Norte, Brazil, and is described by Price (1954). It is clearly a pleurodire, showing a sutured pelvis, and study of the type supports the presence of laterally placed mesoplastra. Antunes and Broin (1988) placed it in the Bothremydidae because the internal mold shows ‘‘une morphologie et des rapports de dimensions conformes a ceux de Bothremys ’’ (Antunes and Broin, 1988: 179). Presumably this refers to the short, broad, anterior plastral lobe seen in both Apodichelys and ‘‘ Bothremys ’’ (now Chedighaii) barberi. However, while this taxon may be a bothremydid, a wide anterior lobe is not sufficient to objectively identify Apodichelys as such. The podocnemidid, Bairdemys venezuelensis (fig. 275) also has a short, wide anterior lobe. Nonetheless, Apodichelys is diagnosable; the wide, nearly horizontal epiplastra are distinct from other Pelomedusoides. However, it has too many missing data to be analyzed in our dataset.</p> <p>CURRENT STATUS: Pelomedusoides incertae sedis.</p> <p>‘‘ Chrysemys ’’ montolivensis Roman, 1897</p> <p>TYPE SPECIMEN: University of Lyon 92839.</p> <p>DISCUSSION: This record consists of a shell with carapace and plastron from the Oligocene of Montoulieu, France. First described by Roman (1897) as an emydid, it was questionably identified as the podocnemidid Neochelys by Broin (1977). Roman has photographs (Roman, 1897) and Broin has line drawings showing sutures, sulci, and a dorsal view of the xiphiplastron (Broin, 1977: fig. 66). Later, Lapparent de Broin and Werner (1998) and Lapparent de Broin (2001) identified this taxon as a bothremydid, but without giving any reasons. The shell is nearly complete, but unfortunately lacks the anteromedial region, so that the nuchal bone, entoplastron, and most of the epiplastra, all areas with useful characters, are missing. The relatively short anterior plastral lobe is typical of bothremydids, but also occurs in podocnemidids (i.e., Bairdemys). The pectoral scale barely reaches the mesoplastron, also found in both bothremydids and podocnemidids. The surface ornamentation appears to be smooth. There are seven neurals, with the seventh and eighth costals meeting on the midline, again found in both podocnemidids and bothremydids. The pubic articulation scar is small, also not unique to either family. At present, this form, while probably a member of the Pelomedusoides, could be either a bothremydid or a podocnemidid. It is inadequate to extend the range of the Bothremydidae into the Oligocene, as claimed by Lapparent de Broin and Werner (1998). While we accept it as diagnosable, it is only marginally so.</p> <p>CURRENT STATUS: Pelomedusoides incertae sedis.</p></div> 	https://treatment.plazi.org/id/4E7B8791CF06FFD6FF9FF95A1647896B	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	GAFFNEY, EUGENE S;TONG, HAIYAN;MEYLAN, PETER A	GAFFNEY, EUGENE S, TONG, HAIYAN, MEYLAN, PETER A (2006): EVOLUTION OF THE SIDE-NECKED TURTLES: THE FAMILIES BOTHREMYDIDAE, EURAXEMYDIDAE, AND ARARIPEMYDIDAE. Bulletin of the American Museum of Natural History 300 (300): 1-698, DOI: 10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2, URL: http://dx.doi.org/10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2
4E7B8791CF03FFCAFD34FE0811E88977.text	4E7B8791CF03FFCAFD34FE0811E88977.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Palaeaspis conybearii (Owen 1849) Gray 1870	<div><p>Palaeaspis conybearii (Owen, 1849) Gray, 1870</p> <p>Palaeaspis bowerbanki (Owen, 1842)</p> <p>Gray, 1870</p> <p>TYPE SPECIMEN: There may be more than one taxon involved in this series of names, as suggested by Broin (1977: 49), although Williams (1954a) synonymized them all as Palaeaspis conybearii. The oldest of the species is Platemys bowerbanki Owen, 1842, with a type that is apparently lost (Williams, 1954a), but the genus Palaeaspis was named by Gray (1870) for Emys conybearii Owen, 1849 (in Owen and Bell, 1849) with BMNH R39449 as a type. Both are partial shells.</p> <p>DISCUSSION: The Early Eocene London Clay of England has yielded a series of shells (Clouter et al., 2000) identifiable as Pelomedusoides, which were reviewed by Williams (1954a), who concluded that there was one species, correctly named Palaeaspis conybearii (Owen). Broin (1977: 48–49) commented on the material and compared it with Taphrosphys, noting that the surface texture and position of the pectoral/abdominal sulcus were similar. However, she concluded that the shell material was poorly described and probably included more than one taxon. A partial skull, BMNH 38953 (Owen, 1850: pl. 29, figs. 1, 2) from Sheppy, Kent, figured and described by Owen (1850) as Platemys bowerbanki, was suggested by Broin (1977: 49) as possibly Erymnochelys. However, Ren Hirayama has recently noted (personal commun.; we are also grateful to Sandra Chapman for assistance) that the skull has a processus trochlearis oticum and appears to be a carretochelyid. Broin (1988: 138) placed ‘‘ Palaeaspis bowerbanki (Owen, 1842) ’’ as possibly being part of Neochelys Bergounioux, 1954 without comment. Lapparent de Broin (2001: 169) placed Palaeaspis Gray, 1970 in the Bothremydidae, also without comment, and we cannot find a previous reference explaining either of these attributions. On the basis of the described shell material (and the BMNH material that we have seen), it is not possible to assign any of the separate (or synonymized) species of the London Clay pleurodire/pleurodires to a family.</p> <p>CURRENT STATUS: Pelomedusoides incertae sedis.</p> <p>‘‘ Podocnemis ’’ somaliensis Walker, 1966</p> <p>TYPE SPECIMEN: Partial shell, Sedgwick Museum, Cambridge, C 54.276 (Walker, 1966).</p> <p>DISCUSSION: This nearly complete shell from the Eocene of Somalia has the sutural pattern preserved, but apparently lacks sulci impressions. Entering it in our dataset produces a whopping 87 % missing data, but the miracle of our ability to analyze meager information resolves ‘‘ Podocnemis ’’ somaliensis with the Bothremydidae, a conclusion apparently consistent with that of Lapparent de Broin (2000a), who listed it as ‘‘ Bothremys somaliensis (Walker, 1966).’’ It is not possible to assign this shell to a genus, however, and its recognition as a bothremydid must be considered tenuous at best.</p> <p>CURRENT STATUS: Bothremydidae incertae sedis.</p> <p>‘‘ Podocnemis ’’ parva Haas, 1978a</p> <p>TYPE SPECIMEN: A nearly complete shell, Hebrew University of Jerusalem, Israel, Department of Zoology collection, HUJP-Testudinata-3 (Haas, 1978a).</p> <p>DISCUSSION: See ‘‘ Podocnemis ’’ judea.</p> <p>‘‘ Podocnemis ’’ judea Haas, 1978b</p> <p>TYPE SPECIMEN: A nearly complete shell, Hebrew University of Jerusalem, Israel, Department of Zoology collection, HUJP 3664.</p> <p>DISCUSSION: Haas (1978a, 1978b) described a series of small shells from the Cenomanian of Israel. The criteria differentiating two species among these shells seem to be within the variation seen in some recent pleurodire species. Apparently Broin (1988) and Lapparent de Broin and Werner (1998) came to the same conclusion, as they only list the older species as valid. They also place parva in Bothremys. When parva/judea is entered in the dataset (83 % missing data) and analyzed in the larger dataset, it resolves as the sister taxon to Foxemys + Polysternon. This is a little surprising considering the large amount of missing data, but the few characters available produce this single cladogram. However, this material has not been reexamined in recent years, and a new assessment of the character distributions is needed to clarify some of the characters that are inconsistent in the figures. It is necessary to leave parva/judea without a generic assignment and place it incertae sedis within the Bothremydini until it is better known.</p> <p>CURRENT STATUS: Bothremydini incertae sedis.</p> <p>‘‘ Taphrosphys ’’ olssoni (Schmidt, 1931)</p> <p>TYPE SPECIMEN: FMNH P14172, partial shell (fig. 267).</p> <p>DISCUSSION: This partial shell was described by Schmidt (1931) from the Eocene of Peru as Podocnemis olssoni. Zangerl recognized its similarities to Taphrosphys and changed it to Taphrosphys olssoni. This was accepted by Gaffney (1975a), who provided comparative diagnoses for T. olssoni and T. sulcatus (table 24). When entered into the dataset, this taxon comes out in a multichotomy with all members of the Taphrosphyini. We remove the species olssoni from Taphrosphys.</p> <p>CURRENT STATUS: Taphrosphyini incertae sedis.</p> <p>‘‘ Taphrosphys ’’ ambiguus (Gaudry, 1890)</p> <p>TYPE SPECIMEN: MNHN-MTA1, a plastron (fig. 267).</p> <p>DISCUSSION: A plastron from the Paleocene of France was named Tretosternum ambiguum by Gaudry (1890:) 251, fig. 355 and reassigned to Taphrosphys by Broin (1977), who redescribed and figured it (Broin, 1977: fig. 4, pl. 4, figs. 9, 10). ‘‘ Taphrosphys ’’ ambiguus has enough characters to enter into the dataset, which, when analyzed, shows it in a multichotomy with all Taphrosphyini. The available material is insufficient to place in a genus (table 24).</p> <p>CURRENT STATUS: Taphrosphyini incertae sedis.</p> <p>‘‘ Taphrosphys ’’ miocenica Collins and Lynn, 1936</p> <p>TYPE SPECIMEN: USNM 13784, anterior lobe of a plastron.</p> <p>DISCUSSION: This partial plastron from the Miocene Calvert Formation of Camp Roosevelt, Maryland, was named Taphrosphys miocenica (Collins and Lynn, 1936: pl. 1). The assignment to Taphrosphys was rejected by Gaffney and Zangerl (1968: 208) because Taphrosphys is characterized by a large intergular scale separating the gular scales, humeral scales, and part of the pectoral scales. In ‘‘ Taphrosphys ’’ miocenica the intergular separates only the gulars and part of the humerals, as in Bothremys. Gaffney and Zangerl therefore assigned ‘‘ T.’’ miocenica to Bothremys. However, Gaffney (1975a) rejected this generic assignment, because the Bothremys scale pattern also occurs in Podocnemis and other taxa and is inadequate for a generic determination. ‘‘ Taphrosphys ’’ miocenica was therefore made a nomen dubium. The Bothremys scale pattern, in fact, occurs widely in Pelomedusoides, within Bothremydidae as well as Podocnemididae. It is notable that Bairdemys (fig. 275; Gaffney and Wood, 2002; Wood and Díaz de Gamero, 1971) has an anterior plastral lobe nearly identical in size, shape, and scale arrangement to that in ‘‘ Taphrosphys ’’ miocenica. Bairdemys has a short, rounded, anterior plastral lobe (fig. 275), as in many bothremydids. Bairdemys occurs in the Miocene of Venezuela and Puerto Rico. However, the group that it belongs to within the Podocnemididae, the Shweboemys Group, is known throughout the Caribbean (Domning and Clark, 1993 [this record contains the posterior end of a lower jaw that is a podocnemidid]; Domning et al., 1997; Sánchez-Villagra et al., 2000; Gaffney and Wood, 2002). Furthermore, an undescribed lower jaw in the South Carolina State Museum (SCSM SC90.16.24) from the Oligocene of South Carolina is very similar to the lower jaw of Bairdemys from Venezuela (we are very grateful to Dr. R. Weems for bringing this specimen to our attention). The fact that Bairdemys and its near relatives are now known to occur in the mid-Tertiary of the Atlantic coast as well as the Caribbean, and that the morphology of ‘‘ Taphrosphys / Bothremys ’’ miocenica is so similar to that group, suggests that this specimen could easily be a podocnemidid and should not be used as a mid-Tertiary record of the Bothremydidae. The anterior plastral lobe is too incomplete to enter into the dataset.</p> <p>CURRENT STATUS: Pelomedusoides incertae sedis.</p> <p>Taquetochelys decorata Broin, 1980</p> <p>TYPE SPECIMEN: MNHN-GDF 847, a right hypoplastron (Broin, 1980: pl. 3, fig. 10).</p> <p>DISCUSSION: These shell fragments from the Aptian of Gadoufaoua, Niger (Broin, 1980), have a surface texture similar to that of Araripemys. The texture is not unique to Araripemys, however. The type alone is not diagnosable as a distinct taxon. It is unique only if locality and age are considered. The described fragments are inadequate to show a sister-group relationship to Araripemys. There are too many missing data to enter into our dataset. If new articulated specimens from the same locality become available, this taxon might become diagnosable.</p> <p>CURRENT STATUS: Pleurodira incertae sedis.</p> <p>TAXA NOMINA DUBIA Apertotemporalis baharijensis Stromer, 1934</p> <p>TYPE SPECIMEN: BSP uncataloged, now lost (Crumly, 1984).</p> <p>DISCUSSION: This partial skull from the Late Cretaceous of Egypt was described and figured by Stromer (1934: plate 1, fig. 1a–c) but was apparently later destroyed in World War II (Crumly, 1984) with much of the Munich collection. The figures show a turtle skull, which Antunes and Broin (1988), Broin (1988), Lapparent de Broin and Werner (1998), and Lapparent de Broin (2000a) assigned to the Bothremydidae. Antunes and Broin (1988) based this on ‘‘Le dessin du reste de crâne montre une morphologie et les dimensions compatibles avec Bothremys et Rosasia …’’ (Antunes and Broin, 1988: 179). In the absence of the original, the only information on ‘‘ Apertotemporalis ’’ is the description and figures in Stromer (1934), which show a badly eroded and damaged partial skull of something that would probably be difficult or impossible to objectively diagnose even if the original were available. Even if new, complete material were to be found at the type locality, identifying it with the type figures would be very argumentative. The only apparent feature of the skull from the figures is a fully enclosed incisura columellae auris, consistent with the Bothremydidae, but also found in other groups. In fact, an Egyptian bothremydid skull, Arenila, has been found and it could very well be the same species as ‘‘ Apertotemporalis,’’ but this is impossible to determine given the absence of a type specimen. The figures alone are inadequate to diagnose the taxon, and in the absence of a type specimen, the taxon should be ignored.</p> <p>CURRENT STATUS: Nomen dubium.</p> <p>Carteremys leithi (Carter, 1852)</p> <p>Williams, 1953</p> <p>TYPE SPECIMEN: None designated in original description of species (Carter, 1852); no specimens seen by subsequent authors; present whereabouts unknown. Williams (1953) based his diagnosis of a new genus on the figures of Carter (1852), which consist of two plates showing a reconstruction based on nine partial specimens. The material figured shows a carapace, plastron, partial skull, and partial lower jaws. If available, this material would presumably allow an adequate diagnosis, but there is no evidence that this material has been available since 1852.</p> <p>LOCALITY AND HORIZON: Possibly Maastrichtian or Paleocene Intertrappean beds of Bombay (Mumbai), India (Wood, 1970).</p> <p>DISCUSSION: ‘‘ Testudo ’’ leithii Carter was originally recognized as a pleurodire by its author, despite being referred to ‘‘ Testudo ’’. Subsequently, Gray (1871) assigned the species to the chelid genus, Hydraspis, which was questioned by Williams (1953), who suggested that the original figures showed a mesoplastron and that the skull looked like Stereogenys, a podocnemidid. However, the original description and Williams’ diagnosis of the genus are inadequate to diagnose this taxon. The original figures are reconstructions. No figure of the original material exists, so that there is no possibility of designating a lectotype on the basis of the figures, as the original figures are reconstructions. If at some future date Carter’s original, properly labeled material becomes available, then this taxon might be resurrected.</p> <p>Wood (1970) added further arguments that C. leithii is a pelomedusid (sensu lato, now equals Pelomedusoides) and concurred in recognizing Carteremys as a diagnosable genus. Jain (1977) added another species, C. pisdurensis, an undoubted Pelomedusoides later reassigned to the genus Shweboemys (Jain, 1986). We concur that this species is a podocnemidid and not a bothremydid. Singh et al. (1998), in the initial announcement of the skull that was later named Sankuchemys, also considered Carteremys a nomen dubium.</p> <p>Williams (1953) also figured a carapace from the Intertrappean beds of Worli Hill, Bombay (Mumbai), that he identified as Carteremys leithii, and which was apparently found in the 1940s by Dr. R. N. Sukheswala. This carapace was figured and described by Singh et al. (1998), along with a plastron anterior lobe. Williams (1953) apparently identified this carapace as Carteremys on the basis of its locality, small size, and surface texture. The association of the plastron with the carapace may not be original, as Williams (1953) specifically stated that the plastron and skull were missing. However, the plastral lobe is of the right size and apparently is from the same locality. The plastron shows very small gular scales with a large pair of intergular scales completely separating the humerals, similar but not identical to the figure in Carter (1852). Therefore, it is quite possible that this shell material could be the same species that Carter (1852) described, and that this is the shell of the skull described as Sankuchemys. However, even if the new shell material were accepted as the shell of Sankuchemys, tenuous at best, it is even harder to argue that these shell specimens are the same species as those described by Carter in 1852.</p> <p>CURRENT STATUS: Nomen dubium.</p> <p>Crassachelys neurirregularis</p> <p>(Bergounioux, 1952)</p> <p>TYPE SPECIMEN: None designated by original author of Gafsachelys neurirregularis Bergounioux, 1952. A neotype designated by Moody (1972) is a carapace fragment in plate 46, figure 2 of Bergounioux (1952).</p> <p>DISCUSSION: In 1972, Moody used the neural number to recognize three genera in the Tunisian Eocene Pelomedusoides. Two of these, Gafsachelys and Eusarkia, had been named, so he added a third for Gafsachelys neurirregularis. In Moody’s scheme, Gafsachelys Stefano, 1903 is restricted to seven neural bones in contact (Moody, 1972: pl. 16); Crassachelys Moody 1972 is characterized by smaller neurals, five in number, some separated by costals meeting on the midline (Bergounioux, 1952: pl. 46, figs. 4, 5; 1956: figs. 22, 23, pl. 10, fig. 2, pls. 11–13; Moody, 1972: pl. 16, fig. 2, pl. 17); and Eusarkia Bergounioux, 1952 is characterized by an absence of neurals (Bergounioux, 1952: pl. 46, figs. 1–3; 1956: fig. 20; Moody, 1972: fig. 3). Broin (1977) and Antunes and Broin (1988) have disputed the use of this character, ascribing it to individual variation and lumping all three genera into Taphrosphys. Broin (1988) and Lapparent de Broin (2000a) also synonymized Crassachelys with Taphrosphys. However, the neotype designated by Moody (1972) consists only of a central part of a carapace showing discontinuous neurals and a Taphrosphys - like texture. Given the variations in the neural pattern in North African Paleogene Pelomedusoides, this neotype must be considered inadequate for a diagnosable taxon.</p> <p>When dealing with this large suite of Tunisian shells, the Moroccan specimens must be kept in mind. Broin (1988) and Lapparent de Broin (2000a) synonymized all these Tunisian taxa as Taphrosphys phosphaticus. Aside from the designation of phosphaticus as a nomen dubium, there is a problem using shell characters alone to diagnose Taphrosphys in light of the new discoveries in Morocco. The Moroccan fauna has yielded a diverse group of taxa related to Taphrosphys. The discovery of a skull-shell association for Ummulisani shows that many shell characters used by earlier authors to diagnose Taphrosphys have a wider distribution, perhaps wider than the tribe Taphrosphyini. Although there are a number of shells known from the Tunisian phosphates, most are steinkerns. Complete shells with extensive bone preserved are relatively rare, so analyzing the possible correlation of neural number with other characters is difficult. Therefore, the identification of alpha taxa among the Tunisian shells is problematic, especially in the absence of any skull-shell associations. It might be possible to recognize some of the best preserved specimens as tribe Taphrosphyini incertae sedis, but unfortunately this excludes most of the type specimens.</p> <p>CURRENT STATUS: Nomen dubium.</p></div> 	https://treatment.plazi.org/id/4E7B8791CF03FFCAFD34FE0811E88977	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	GAFFNEY, EUGENE S;TONG, HAIYAN;MEYLAN, PETER A	GAFFNEY, EUGENE S, TONG, HAIYAN, MEYLAN, PETER A (2006): EVOLUTION OF THE SIDE-NECKED TURTLES: THE FAMILIES BOTHREMYDIDAE, EURAXEMYDIDAE, AND ARARIPEMYDIDAE. Bulletin of the American Museum of Natural History 300 (300): 1-698, DOI: 10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2, URL: http://dx.doi.org/10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2
4E7B8791CF1EFFC8FF9DFA0916928ECA.text	4E7B8791CF1EFFC8FF9DFA0916928ECA.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Gafsachelys moularensis Bergounioux 1955	<div><p>Gafsachelys moularensis Bergounioux, 1955a</p> <p>TYPE SPECIMEN: ‘‘G1’’, probably in the collection of the Mines de Moularès, Tunisia, a partial shell figured in Bergounioux (1956: pl. 10, fig. 1).</p> <p>DISCUSSION: Bergounioux (1956: fig. 21) did provide some comic relief for hardpressed paleontologists when he named a new species Gafsachelys moularensis by describing a turtle shell backwards (Bergounioux, 1956: fig. 21; see also G. neurrirregularis, fig. 24), with the pygal labeled nuchal and vice versa (showing that all turtle shells look alike, no matter what direction they are going). This was only to be expected from the author of the world’s oldest turtle, Archaeochelys pougeti Bergounioux, 1938, a Permian concretion.</p> <p>CURRENT STATUS: Nomen dubium.</p> <p>Gafsachelys phosphatica Stefano, 1903</p> <p>TYPE SPECIMEN: A partial shell steinkern in the MNHN, formerly in L’Ecole Nationale Supérieure des Mines de Paris.</p> <p>DISCUSSION: Stefano (1903) was the first to study turtle remains from the Ypresian of Gafsa, Tunisia. In 1903 he created Gafsachelys phosphatica on the basis of a partial shell in the collection of ‘‘Ecole Nationale Supérieure des Mines de Paris’’ and placed it in the Chelydridae. Bergounioux (1952) correctly rejected the species phosphatica (but illegally) and created neurirregularis as the replacement ‘‘ type species’’ of the genus Gafsachelys. He placed this genus in ‘‘Family Incertae sedis’’ in Cryptodires. Bergounioux (1956) erected another species of Gafsachelys, G. moularensis, and included Gafsachelys in the family Eusarkiidae, created by the same author in 1952 (Bergounioux, 1952, 1955b, 1956). Moody (1972) rehabilitated Gafsachelys phosphatica Stefano, 1903 and characterized it by seven continuous neurals. He assigned four more shells in the Metlaoui Museum, Tunisia, to this species. Broin (1977) reexamined the type specimen of Gafsachelys phosphatica and confirmed that it does have the continuous series of neurals. She pointed out, however, that this specimen cannot even be assigned to Pelomedusoides with certainty since cheloniids are also present in the same locality, and the latter also have narrow neurals. She rejected Gafsachelys phosphatica since it is based on an indeterminate specimen. Moody and Buffetaut (1981) reaffirmed their recognition of the three monotypic genera, Gafsachelys, Crassachelys, and Eusarkia. Gafsachelys (and Eusarkia and Crassachelys) have been synonymized with Taphrosphys by Antunes and Broin (1988), Broin (1988), and Lapparent de Broin (2000a).</p> <p>Examination of the holotype of Gafsachelys phosphatica Stefano by us supports Broin’s original (1977) assessment that the holotype is not diagnosable. The dubious assignment of better specimens to this taxon by later authors does not make the holotype any more diagnosable or the name any more available.</p> <p>CURRENT STATUS: Nomen dubium.</p> <p>Naiadochelys ingravata Hay, 1908</p> <p>TYPE SPECIMEN: AMNH 6078.</p> <p>DISCUSSION: The type and only known specimen of this taxon is the posterior part of a left xiphiplastron, AMNH 6078 (Hay, 1908: fig. 133). It was given to an AMNH archeologist working at Chaco Canyon, New Mexico, in 1900 by Native Americans and is presumably from the San Juan Basin, Late Cretaceous–Eocene. It agrees closely in size, shape of the ischiac scar, and smooth external surface with YPM 3608 Chedighaii (formerly Bothremys) barberi. Unfortunately, these features are widespread in Pelomedusoides and inadequate to objectively identify AMNH 6078. This taxon is considered to be incertae sedis at the level of Pelomedusoides, as these features occur in both Bothremydidae and Podocnemididae. However, if this fragment did come from the San Juan Basin, it is possible that it belongs to Chedighaii hutchisoni, presently known only from a skull.</p> <p>Broin (1988) synonymized Naiadochelys ingravata with Taphrosphys sulcatus, but Taphrosphys is unique among pleurodires in having a small, circular ischiac scar, quite different from the large triangular scar in Naiadochelys and in most other pleurodires. Naiadochelys ingravata also has a smooth external surface texture, different from the pebbled surface of Taphrosphys.</p> <p>CURRENT STATUS: Nomen dubium.</p> <p>‘‘ Najadochelys ’’ (sic) patagonica Staesche, 1929</p> <p>‘‘ Najadochelys ’’ (sic) major Staesche, 1929</p> <p>TYPE SPECIMEN: Unclear. DISCUSSION: In keeping with the tradition of naming useless fragments, Staesche (1929) described a collection of fragments from the Late Cretaceous (now Paleocene) of Argentina as containing the new taxa ‘‘ Najadochelys ’’ patagonica and ‘‘ N.’’ major. The reasons for identifying these (and misspelling the generic name) with Hay’s fragment are unclear, but presumably one unidentifiable taxon deserves a few more. Broin (1977: 31) suggested that these were ‘‘restes d’un ancien Chélide´’’ (Broin, 1977: 31), which was repeated in Broin and Fuente (1993). The Staesche material, as figured, is nearly identical with fossil chelids in the Museo de la Plata seen by one of us (E.S.G.), and we concur with this identification.</p> <p>CURRENT STATUS: Nomen dubium for both species.</p> <p>‘‘ Podocnemis ’’ lata Ristori, 1895</p> <p>TYPE SPECIMEN: A partial carapace plus some fragments, uncataloged, supposedly in a museum in Italy, current whereabouts unknown.</p> <p>DISCUSSION: The type and only known specimen is from the Miocene of Malta, described and figured by Ristori (1895). The carapace is unusual, but not unique, in having costals 6–8 meeting on the midline, but otherwise it has no distinguishing features. Lapparent de Broin and Werner (1998) and Lapparent de Broin (2001) identified it as a bothremydid, but gave no reasons, nor did they indicate if they had seen, or even found, the specimen, which we have not. The figured carapace is similar to bothremydids like Rosasia and Chedighaii barberi in having (probably) a posterolaterally expanded shell and a similar shell margin. However, these features are not unique to bothremydids. This shell could be a podocnemidid or a bothremydid, but it is inadequate as a basis for extending the range of the Bothremydidae into the Miocene, as claimed by Lapparent de Broin and Werner (1998). The original description is detailed and there is a good figure, but the specimen consists only of the posterior two-thirds of a carapace and is not sufficient to distinguish it as a unique taxon.</p> <p>CURRENT STATUS: Nomen dubium.</p> <p>Sokotochelys umarumohammedi Halstead, 1979b</p> <p>TYPE SPECIMEN: ‘‘ Sokoto State Government Palaeontological Collection’’ SOSG no. 1. Probably no longer exists. DISCUSSION: See below.</p></div> 	https://treatment.plazi.org/id/4E7B8791CF1EFFC8FF9DFA0916928ECA	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	GAFFNEY, EUGENE S;TONG, HAIYAN;MEYLAN, PETER A	GAFFNEY, EUGENE S, TONG, HAIYAN, MEYLAN, PETER A (2006): EVOLUTION OF THE SIDE-NECKED TURTLES: THE FAMILIES BOTHREMYDIDAE, EURAXEMYDIDAE, AND ARARIPEMYDIDAE. Bulletin of the American Museum of Natural History 300 (300): 1-698, DOI: 10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2, URL: http://dx.doi.org/10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2
4E7B8791CF87FF43FD03FB8C17588E93.text	4E7B8791CF87FF43FD03FB8C17588E93.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Galianemys emringeri	<div><p>Galianemys emringeri and Galianemys whitei</p> <p>In this section, both species of this genus are described together. The Galianemys species are quite similar to each other, and it makes sense to the senior author to combine the descriptions to avoid repetition. Galianemys is described and figured more extensively than some other taxa because it is a comparatively generalized bothremydid, known from a relatively large array of good material. The two species are represented by a total of 13 skulls, 6 of G. emringeri and 7 of G. whitei (table 9). Of these, G. whitei has six relatively complete skulls, and G. emringeri has three relatively complete skulls. Character variation in the genus is listed in table 9. In addition to the figures grouped with the descriptions (figs. 81–100), the reader should be aware of other Galianemys figures in the character descriptions section: figure 277 (foramen posterius canalis carotici interni), figure 278 (septum orbitotemporale), figure 280 (orbital floor), and figure 284 (quadrate). Much of this section is modified from Gaffney, Tong, and Meylan (2002) by the addition of new material and more comparisons. Galianemys is also shown in a series of CT scans on the DigiMorph University of Texas website: http://www.digimorph.org/ specimens/ Galianemys_emringeri /.</p> <p>Galianemys is most closely related to Cearachelys. They make up the tribe Cearachelyini.</p> <p>PREFRONTAL (figs. 81, 89, 97)</p> <p>Preservation: The prefrontal is preserved in Galianemys whitei in AMNH 30036, 29987, 29986, 30028, 30027, 30555, and in MDEt 45. In Galianemys emringeri it is preserved in AMNH 30035, 30037, 29985,</p> <p>and 30040. It can be seen particularly well in AMNH 30027 and 29986 where the left prefrontal is lost, allowing the internal surfaces on the right side to be seen.</p> <p>Contacts: As in Pelusios and all other Pelomedusoides, the prefrontal in both species of Galianemys contacts the maxilla anteroventrolaterally, the frontal posteriorly, and the other prefrontal medially. In Galianemys emringeri the prefrontal-frontal suture trends posteromedially for a short distance medial to the orbital margin, then trending anteromedially to form a midline projection of the frontal. In G. whitei the suture is nearly straight in AMNH 29986, 29987, 30036, 30027, 30555, and in MDEt 45. In AMNH 30028 the suture is asymmetric with the frontal projecting anteriorly on the right side but not on the left. Cearachelys and Kurmademys have an anteriorly convex suture, but it is nearly straight in Bothremys and Rosasia and slightly curved in other genera.</p> <p>Structures: The prefrontal in Galianemys is similar to that in other Pelomedusoides. The dorsal plate forms the anterodorsal margin of the orbit and the dorsal margin of the apertura narium externa. The margin is slightly protruding over the apertura in Galianemys, as in most Pelomedusoides, but there is some variation within the available specimens. A specimen of Galianemys whitei, AMNH 29987, has a much thicker margin that forms a slightly concave profile in lateral view rather than convex, as in all the other skulls. The skulls of G. emringeri and G. whitei do not differ consistently in the prefrontal. The prefrontal in Galianemys is very similar to that bone in Cearachelys and Kurmademys.</p> <p>FRONTAL (figs. 81, 89, 97)</p> <p>Preservation: The frontal in Galianemys whitei is preserved in AMNH 29987, 29986, 30036, 30027, 30028, 30555, and in MDEt 45.</p> <p>In Galianemys emringeri it is preserved in AMNH 30037, 30040, 30035, and 29985. It is most visible in AMNH 30027, 29986, and 30037.</p> <p>Contacts: The frontal contacts in Galianemys are with the prefrontal anteriorly, postorbital posterolaterally, parietal posteriorly, and the other frontal medially. These are the same in both Galianemys species and in Cearachelys.</p> <p>Structures: The frontal is very similar in both Galianemys and Cearachelys. The ridge defining the sulcus olfactorius is deeper in Galianemys than in Cearachelys. There is some variation in this feature among the Galianemys specimens, but they are all deeper than in Cearachelys, Kurmademys, and the Pelomedusidae. The interorbital width is wider in Galianemys than in Cearachelys, Kurmademys, and the Pelomedusidae. This is the result of a greater overhang of the frontal over the fossa orbitalis lateral to the sulcus olfactorius.</p> <p>PARIETAL (figs. 81, 89, 97)</p> <p>Preservation: The parietal is preserved to some extent in all the Galianemys specimens. It is complete in AMNH 30028 and 30555 and is nearly complete in AMNH 29987 (all Galianemys whitei). In Galianemys emringeri, AMNH 30037 has the most complete parietals.</p> <p>Contacts of dorsal plate: The parietal contacts in Galianemys are with the frontal anteriorly, the postorbital anterolaterally, and with the other parietal medially.</p> <p>Structures of dorsal plate: The degree of emargination in Galianemys is similar to that seen in Cearachelys but is not as extensive. Kurmademys and the pelomedusids have the most extreme emargination, with Cearachelys being more covered and Galianemys more covered than Cearachelys. The temporal skull roof consists largely of parietal and postorbital. Galianemys is more emarginate than Foxemys. The other bothremydids do not have complete preservation of the roof for comparison.</p> <p>In contrast to Cearachelys, Kurmademys, and pelomedusids, the parietal of Galianemys is wider posteriorly near the midline along the supraoccipital contact. Although the temporal emargination depth is not much less than in Cearachelys, the temporal opening in Galianemys is more covered due to the wider parietal roof along its posterior extension.</p> <p>Contacts of processus inferior parietalis: The processus inferior parietalis (fig. 97) contacts the palatine anteroventrally, the pterygoid ventrally, the prootic posteroventrally, and the supraoccipital posteriorly, as in Cearachelys, the other Pelomedusoides, and most turtles.</p> <p>Structures of processus inferior parietalis: The palatine has a dorsal extension, higher than the crista pterygoidea, so the processus inferior parietalis is deeper posteriorly than anteriorly. The processus is relatively long in contrast to most Taphrosphyini but like Phosphatochelys. The parietal forms the anterodorsal margin of the foramen nervi trigemini.</p> <p>JUGAL (figs. 81, 89, 278, 280)</p> <p>Preservation: The jugal is preserved in all specimens of both species of Galianemys. In AMNH 29985, the type of Galianemys emringeri, the jugal is incomplete posteriorly, but in AMNH 30037 and 30035 it is complete.</p> <p>Contacts of lateral plate: The jugal in Galianemys contacts the postorbital dorsally, the maxilla anteroventrally, and the quadratojugal posteroventrally. These are as in Cearachelys except that the jugal of Galianemys is completely separated from the orbital margin by a wide postorbital-maxilla contact.</p> <p>Structures of lateral plate: The jugal of Galianemys is excluded from the orbital margin by a postorbital-maxilla contact and is excluded from the cheek margin by a quadratojugal-maxilla contact.</p> <p>Contacts of medial process: The medial jugal process is exposed in the orbital floor and the septum orbitotemporale (figs. 278, 280). In the orbital floor it contacts the maxilla anteriorly and anterolaterally, the palatine medially, and the postorbital posterodorsally. The postorbital and maxilla have a strong lateral contact widely separating the jugal exposure in the orbital floor from the cheek jugal exposure. In Cearachelys the postorbital and maxilla barely meet along the orbital margin barely separating the two parts of the jugal. The jugal is widely exposed on the orbital margin in Kurmademys and pelomedusids. The jugal is also exposed in the septum orbitotemporale. On its posterior surface, the jugal contacts the postorbital dorsomedially, the pterygoid posteromedially, and the maxilla anteroventrally. In Galianemys whitei the jugal also contacts the palatine ventromedially but in Galianemys emringeri this contact is smaller (AMNH 30037, 30035) or absent (AMNH 29985), and the maxilla and pterygoid are closer to each other.</p> <p>Structures of medial process: The medial process of the jugal floors the orbit and forms part of the postorbital wall. In Galianemys emringeri the jugal is restricted to the vertical surface of the wall, but in G. whitei the jugal curves anteriorly and forms a small part of the triturating surface. This area of the triturating surface has a shallow but definitive depression in G. whitei, but it is flat in G. emringeri.</p> <p>QUADRATOJUGAL (figs. 81, 89)</p> <p>Preservation: The quadratojugal is present in Galianemys whitei specimens at least in part in AMNH 30036 and 29986, but it is most complete in AMNH 30028, 30555, and 29987. In Galianemys emringeri the quadratojugal is almost complete in AMNH 30035 and partial in AMNH 30037 and 30040.</p> <p>Contacts: The quadratojugal contacts the maxilla anteroventrally, preventing exposure of the jugal on the ventral edge of the skull and producing the complete absence of a cheek emargination. Anteriorly the quadratojugal contacts the jugal and anterodorsally it contacts the postorbital. Posteriorly the quadratojugal has a long S-shaped contact with the quadrate; above this a narrow posterior process of the quadratojugal meets a narrow anterior process of the squamosal (preserved in AMNH 30040 and 30035 of Galianemys emringeri).</p> <p>Structures: The quadratojugal is a large, flat plate that forms about half of the cheek in Galianemys. Cheek emargination as seen in Kurmademys is completely absent, and even the slight emargination seen in the cheek of Cearachelys is absent. Otherwise, the quadratojugal of Galianemys is very similar to that in Cearachelys in contacts, size, and shape.</p> <p>SQUAMOSAL (figs. 81, 88, 89, 98, 284)</p> <p>Preservation: The squamosal is present in AMNH 30037, 30040, and 30035 in Galianemys emringeri, and in AMNH 30028, 30027, 30036, 30555, 29987, and 29986 in Galianemys whitei.</p> <p>Contacts: Squamosal contacts do not vary much in Pelomedusoides. The conical squamosal fits on the quadrate, contacts the opisthotic medially, and has a short anterior process reaching the quadratojugal anterodorsally.</p> <p>Structures: The cone shape of the squamosal in Galianemys is very similar to that seen in Cearachelys. There is no vertical flange on its ventral surface, as in Taphrosphys.</p> <p>POSTORBITAL (figs. 81, 89, 278)</p> <p>Preservation: At least some of the postorbital is present in four Galianemys emringeri specimens and all seven Galianemys whitei skulls. Nearly complete postorbitals are in AMNH 30035, 30040, and 30037 for G. emringeri and AMNH 30028, 30555, and 29987 for G. whitei.</p> <p>Contacts of lateral plate: The lateral plate of the postorbital forms part of the temporal roof and in Galianemys contacts the frontal anteromedially, the parietal posteromedially, the maxilla anteroventrally, the jugal ventrolaterally, and the quadratojugal posterolaterally.</p> <p>Structures of lateral plate: The postorbital lateral plate forms most of the posterior orbital margin and extends posteriorly to reach the edge of the temporal margin.</p> <p>Contacts of medial process: The medial process is exposed on both sides of the septum orbitotemporale with these contacts: palatine ventromedially, jugal ventrally, maxilla ventrolaterally, and frontal dorsomedially. In posterior view of the septum (fig. 278) the medial process of the postorbital has these contacts: parietal dorsomedially, jugal ventrolaterally, and pterygoid ventromedially. The strong postorbital-maxilla contact that broadly excludes the jugal from the orbital margin is unique among pleurodires.</p> <p>Structures of the medial process: The medial process of the postorbital forms part of the roof and the lateral wall of the sulcus palatinopterygoideus and most of the septum orbitotemporale. All of these structures are very similar in Galianemys and Cearachelys.</p> <p>PREMAXILLA (figs. 81, 82, 89, 96)</p> <p>Preservation: The premaxilla is present in AMNH 30035 and 30037 in Galianemys emringeri, but in Galianemys whitei only the presumed juvenile, MDEt 45, and AMNH 30555, have the premaxilla preserved. This is unfortunate because, as preserved, this bone differs in the two species.</p> <p>Contacts: The usual posterolateral contacts with the maxilla and with the other premaxilla on the midline occur in all four specimens. In AMNH 30037 and 30035 the vomer is not preserved and the premaxilla ends in a free margin on the apertura narium interna. But in MDEt 45 and AMNH 30555, the vomer is present and contacts the posteromedial margins of both premaxillae.</p> <p>Structures on dorsal surface: In all four specimens the anterior margins of the premaxillae are broken, but they form the ventral margin of the apertura narium externa. In AMNH 30037 the premaxilla forms a high median ridge on the midline contact of the premaxillae, not seen in Cearachelys but similar to one in Kurmademys, partially dividing the fossa nasalis into paired choanal troughs. This ridge is not developed in MDEt 45, although whether this could be growth related is unknown. The ridge is not preserved in AMNH 30555.</p> <p>Structures on ventral surface: The ventral surface of the premaxilla forms part of the labial ridge and the triturating surface. The premaxillary parts of these, as seen in the specimens available, are significantly different. In Galianemys emringeri, AMNH 30035 and 30037, the ridge is very thick, deep, and blunt. In Galianemys whitei, MDEt 45 and AMNH 30555, it is thin, shallow, and acute. Some degree of this variation is presumed to persist in the adult because G. emringeri has a thicker and blunter labial ridge than does G. whitei. In AMNH 30037 the premaxilla has the thick labial ridge anteriorly; posterior to that is an inclined triturating surface; and posterior to that is a more inclined surface forming a deep median concavity. Where the two surfaces meet, the foramen praepalatinum penetrates the bone. In MDEt 45 the foramen is visible on each side, but the entire surface posterior to the labial ridge is flat; there is no inclination and no median concavity. In MDEt 45, a medial process of the maxilla reaches the vomer to prevent the premaxilla from reaching the apertura narium interna. It is, of course, possible that MDEt 45 is yet a third species distinct from G. emringeri and G. whitei, but it does agree with G. whitei in other features.</p> <p>MAXILLA (figs. 81, 82, 89, 90, 97, 280)</p> <p>Preservation: The maxilla is present and nearly complete in all seven Galianemys whitei skulls and in four of the Galianemys emringeri skulls (AMNH 30037, 29985, 30035, and 30040); most show the sutures clearly.</p> <p>Contacts of vertical plate: The vertical plate of the maxilla contacts the premaxilla anteromedially, the postorbital posterodorsally, the jugal posterodorsally (posterior to the postorbital), and the quadratojugal posteriorly.</p> <p>Structures of vertical plate: The vertical plate of the maxilla forms the ventral orbital margin, the labial ridge of the triturating surface, and the anterior part of the cheek. The dorsal process of the maxilla lies between the apertura narium externa, and the orbit and is similar in size to that in Cearachelys, but thicker than in Kurmademys.</p> <p>The snout just anterior to the orbit of some Galianemys specimens is more pinched, bent toward the midline, than others. In AMNH 29987 the pinching is most pronounced but other skulls of Galianemys whitei, AMNH 30036, 30028, 30555, and 29986, do not show this. This area of the maxilla in AMNH 29987 is rugose, and the pinching may be a pathology or just individual variation. The degree of pinching, however, is the same on both sides. In Galianemys emringeri there is a slight pinching of the snout in the same area, but not to the extent seen in AMNH 29987. At present we interpret this as an individual variation of AMNH 29987.</p> <p>Contacts of horizontal plate: The horizontal plate (in ventral view) contacts the premaxilla anteromedially, the palatine posteromedially, and the jugal posteriorly. Among the 10 Galianemys skulls, the vomer is preserved in AMNH 30555 (fig. 96), G. whitei, and MDEt 45, a presumed juvenile of G. whitei. In both specimens the maxilla on both sides sends a process medially to meet the vomer and prevent the premaxilla from reaching the margin of the apertura narium interna. The condition is not determinable in either Cearachelys or Kurmademys.</p> <p>Structures of horizontal plate: The horizontal plate of the maxilla forms the floor of the orbit in dorsal view (fig. 280). The maxilla forms the ill-defined lateral edge of the foramen orbito nasale, as in Cearachelys and other Pelomedusoides.</p> <p>The horizontal plate in ventral view forms most of the triturating surface (figs. 82, 90). The triturating surface in Galianemys is very similar to that in Cearachelys in width and shape. It is slightly narrower than in Kurmademys. The labial ridge in Galianemys is distinctly thicker in both species than in Cearachelys and Kurmademys. The ridge is also thicker in Galianemys emringeri than in Galianemys whitei. In AMNH 30035 the ridge is thicker than in any other Galianemys specimen, but AMNH 29985 and 30037, the other two G. emringeri skulls, also have a thicker labial ridge than in any G. whitei skull. The type of G. whitei, AMNH 29987, has the thickest labial ridge in that species but it is still narrower than any of the G. emringeri skulls. Also, the labial ridge in G. whitei is relatively straight, but in G. emringeri, particularly AMNH 30035 and 30037, the ridge has a slight medial trend anteriorly, making it thicker there.</p> <p>At this point we note that AMNH 30035 (figs. 81–84) differs from other Galianemys emringeri skulls in being much larger, wider, more robustly ossified, and in having thicker labial ridges. Because it has the other features of G. emringeri, we include it in this species. The maxilla of this skull is particularly distinct in its more massive form and ossification.</p> <p>The triturating surface is flat in the skulls of Galianemys emringeri, but in G. whitei there is a very shallow concavity formed mostly by the jugal, which is exposed on the triturating surface in this species. The palatine forms a significant part of the triturating surface in Galianemys, as in Cearachelys and Kurmademys.</p> <p>VOMER (figs. 89, 96)</p> <p>Preservation: The vomer is present only in two specimens of Galianemys, MDEt 45 and AMNH 30555, both Galianemys whitei.</p> <p>Contacts: The vomer contacts the premaxilla anteriorly, the maxilla anterolaterally, and the palatines posteriorly.</p> <p>Structures: The vomer in Galianemys is slightly narrower than in Cearachelys, but it is expanded at both ends and separates the apertura narium interna. In contrast to most turtles that have the paired foramen praepalatinum on the vomer near the premaxilla suture, in Galianemys the foramina are in the middle of the premaxilla and not in the vomer.</p> <p>PALATINE (figs. 81, 82, 89, 90, 97)</p> <p>Preservation: The palatine is present in all seven Galianemys whitei skulls and in four of the Galianemys emringeri skulls. It is missing in MDEt 46 and AMNH 30026. Only MDEt 45 has the thin, original anterior margin completely preserved.</p> <p>Contacts: The palatine contacts the vomer anteromedially (preserved only in AMNH 30555 and MDEt 45), the maxilla anterolaterally, the other palatine medially, the pterygoid posteriorly, and the jugal posterolaterally (except in AMNH 29985, see Jugal). On the dorsal surface the palatine contacts the parietal posteriorly, the jugal medially, the maxilla anteromedially, and the postorbital laterally (fig. 280).</p> <p>Structures on dorsal surface: On the dorsal surface the palatine forms the posteromedial part of the orbital floor and the posterior margin of the foramen orbitonasale. There is a low dorsal process that meets the processus inferior parietalis (fig. 97). Lateral to this the palatine forms the anterior floor of the sulcus palatinopterygoideus.</p> <p>Structures on ventral surface: Basically a flat bone, the palatine has different relations to surrounding bones on its ventral compared with its dorsal surfaces. On the ventral surface it forms the posteromedial part of the triturating surface and the posterior part of the choanal openings. These are all similar to Cearachelys. Posterolaterally the palatine forms the medial half of the foramen palatinum posterius. The foramen lies along a strong anterolateral process that is better developed in Galianemys than in Cearachelys and Kurmademys.</p> <p>QUADRATE (figs. 81, 89, 284)</p> <p>Preservation: The quadrate is present in all 13 Galianemys skulls, although it is detached in MDEt 45 and incomplete in AMNH 29985. All other specimens have at least one complete quadrate.</p> <p>Contacts on lateral surface: In lateral view the quadrate contacts the quadratojugal anteriorly and the squamosal posterodorsally.</p> <p>Structures on lateral surface: In lateral view the quadrate in Galianemys (fig. 284) does not form part of the temporal margin due to the quadratojugal-squamosal contact. The cavum tympani and its associated structures dominate the lateral view. The cavum itself is slightly deeper in Galianemys than in Cearachelys, but as in Cearachelys, there is no fossa precolumellaris, a structure seen in Kurmademys. The incisura columellae auris is completely closed by the quadrate and separated from the eustachian tube opening by bone in Galianemys. In Cearachelys the incisura is open, but it is closed in Kurmademys as in Galianemys (see also figs. 303 and 304 for distribution of these characters). The incisura in Galianemys is a teardrop-shaped foramen with the acute tip pointed posteriorly, in contrast to the symmetric oval of Kurmademys and most bothremydids. The apex of the teardrop shape in Galianemys is continued posteriorly as a trough that opens into the sulcus eustachii (the eustachian tube notch).</p> <p>The antrum postoticum in Galianemys (fig. 284) is present and completely developed and is best seen in AMNH 30037, 29985 (internally, with the squamosal removed), and 30027. Its size varies slightly but perceptibly among the available skulls. It is smaller in AMNH 29987, 30028, and 29986, all G. whitei, and larger in AMNH 29985, 30037, and 30035, all G. emringeri. This is consistent with the recognition of two species, but AMNH 30036, a specimen of G. whitei, has a larger antrum, similar to that in G. emringeri. Among other genera, the antrum postoticum of Galianemys is smaller than that in Cearachelys and much smaller than that in Kurmademys and pelomedusids. It is larger, however, than in Taphrosphys and Bothremys.</p> <p>The groove for the eustachian tube, the sulcus eustachii, in Galianemys is a nearly enclosed oval trending dorsomedially to ventrolaterally (fig. 284). It is open at its lateral end. It is narrow and extends for half of the distance between the incisura collumellae auris and the edge of the cavum tympani; there is no bone covering the other half. In Kurmademys the eustachian opening is wide open laterally, not constricted. In Cearachelys the sulcus eustachii and the incisura columellae auris are confluent. In other bothremydids, such as Taphrosphys and Bothremys, the sulcus eustachii is more widely open laterally and farther separated from the incisura columellae auris.</p> <p>Contacts on dorsal and anterior surface: The quadrate contacts the prootic anteromedially, the supraoccipital medially, the squamosal posterolaterally, and the opisthotic posteromedially. The supraoccipital contact occurs in most bothremydids, except the Taphrosphyini and Zolhafah.</p> <p>Structures on dorsal and anterior surface: The foramen stapedio-temporale in Galianemys, formed in the quadrate-prootic suture, is on the anterior surface of the otic chamber (fig. 97), as in nearly all other bothremydids, but it is not very close to the foramen nervi trigemini, as in Bothremys and other genera. In Kurmademys this foramen is slightly more posterior, just enough to make it more visible in dorsal view. It is only slightly more anterior in Kurmademys than in pelomedusids, and we judge the condition to be the same in both and primitive with respect to all other bothremydids.</p> <p>Contacts on ventral surface: In ventral view the quadrate contacts the pterygoid anteromedially, the basisphenoid medially, the basioccipital posteromedially, and the squamosal posterolaterally. In Galianemys emringeri the quadrate forms the posterior part of the deep fossa pterygoidea that exposes the prootic, so in that species there is a small quadrate-prootic contact.</p> <p>Structures on ventral surface: On the ventral surface, the quadrate forms the lateral margin of the foramen posterius canalis carotici interni in Galianemys whitei, but not in G. emringeri (see Pterygoid for discussion). In G. emringeri the quadrate and the prootic form a portion of the posterior wall of the large fossa pterygoidea (see Pterygoid for discussion). The condylus mandibularis in Galianemys is very similar in both species in position and shape. The condylus mandibularis is in about the same position with</p> <p>30555. [E. Ullo, del.]</p> <p>respect to the condylus occipitalis in Cearachelys and Galianemys, but in Kurmademys the condylus mandibularis is more anteriorly placed. The foramen for the chorda tympani is preserved in nearly all the Galianemys skulls and it is very close to its position in pelomedusids.</p> <p>Contacts in posterior view: The quadrate in Galianemys contacts the squamosal dorsolaterally, the opisthotic dorsomedially, the exoccipital medially, and the basioccipital ventromedially.</p> <p>Structures in posterior view: In posteri- or view the quadrate forms a number of structures in the occipital area (figs. 87, 88, 98–100). The quadrate forms the lateral margin of the fenestra postotica and its subdivisions. In Galianemys the fenestra postotica is preserved in nine skulls. In two of these the fenestra is subdivided into smaller foramina; in the rest there may be low ridges or spurs but these do not connect to completely subdivide the fenestra. The subdivided specimens are AMNH 30037, a skull of Galianemys emringeri, and AMNH 30027, a skull of G. whitei. Neither species shows more of a tendency toward subdivision than the other among the available material. In AMNH 30037 the fenestra postotica is subdivided into two foramina, an upper one, presumably for the stapedial artery, and a lower one, presumably for the lateral head vein. In AMNH 30027, however, there are three foramina as a result of the lower foramen being further subdivided into two. One of these must be the lateral head vein, but the other is a mystery. Wow. One foramen is ventral and the other ventrolateral. In AMNH 30027 this subdivision into three foramina was present on both sides, but was broken during preparation. The other skulls of both Galianemys species have variably developed grooves or spurs that are less ossified indications of these structures. In any case, the subdivision of the fenestra postotica in Galianemys is interpreted as an individual variation. In most individuals it is open as a narrow gap from the foramen jugulare posterius to the aditus canalis stapediotemporalis, a condition also seen in Cearachelys.</p> <p>PTERYGOID (figs. 81, 82, 89, 90, 97, 277)</p></div> 	https://treatment.plazi.org/id/4E7B8791CF87FF43FD03FB8C17588E93	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	GAFFNEY, EUGENE S;TONG, HAIYAN;MEYLAN, PETER A	GAFFNEY, EUGENE S, TONG, HAIYAN, MEYLAN, PETER A (2006): EVOLUTION OF THE SIDE-NECKED TURTLES: THE FAMILIES BOTHREMYDIDAE, EURAXEMYDIDAE, AND ARARIPEMYDIDAE. Bulletin of the American Museum of Natural History 300 (300): 1-698, DOI: 10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2, URL: http://dx.doi.org/10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2
4E7B8791CE43FEECFD7FFF4717E18ECA.text	4E7B8791CE43FEECFD7FFF4717E18ECA.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Araiochelys Gaffney & Tong & Meylan 2006	<div><p>Araiochelys is slightly narrower than in B. maghrebiana, but about the same as in C. hutchisoni.</p> <p>JUGAL (figs. 122–125)</p> <p>Preservation: The jugal is preserved in THUg 3338 on the palate, in the right fossa orbitalis, and on both cheeks. The posterior and ventral limits are probably only represented by broken edges on both sides. The posteroventral edge of the jugal is not known, and it is shown as incomplete in the restoration.</p> <p>Contacts: The jugal in Araiochelys has a complex contact pattern. On the ventral surface the jugal contacts the maxilla anterolaterally and the palatine medially. There is a narrow posteromedial contact with the pterygoid. In Bothremys, Zolhafah, and Rosasia, the jugal is also exposed on the palate between maxilla and palatine, but the degree of exposure varies. In B. cooki the jugal is widely exposed, with the maxilla and palatine being widely separated posterior to the jugal. In B. maghrebiana the jugal has its smallest exposure; it is present only in the dorsal tip of the triturating surface pit, and a broad palatine-maxilla contact is present posterior to the jugal. Araiochelys has an intermediate condition with the jugal exposed in the pit and in a narrow band from the pit to the edge of the fossa temporalis inferior. The palatine and maxilla are separated by the jugal, but not to the extent seen in B. cooki. In Zolhafah and Rosasia the pit is not as completely conical as in Bothremys and Araiochelys, even though the top of the pit is still formed by the jugal at its tip. In both there is no palatine-maxilla contact and the jugal is closer to the fossa temporalis inferior than it is in Bothremys and Araiochelys.</p> <p>On the lateral surface of the skull in Araiochelys, the jugal contacts the maxilla anteroventrally and the postorbital dorsally. Its likely contact with the quadrate and/or quadratojugal is not determinable due to damage. In the floor of the fossa orbitalis the jugal contacts the palatine medially and the maxilla anterolaterally.</p> <p>Structures: The jugal forms part of the triturating surface and part of the cheek. The triturating surface is dominated by the large conical pit formed by jugal, maxilla, and palatine. The upper part of the pit and part of the wall between the pit and the fossa temporalis inferior are formed by the jugal. In contrast to Araiochelys, the jugal in Bothremys cooki forms all of the pit and the wall, and in B. maghrebiana the jugal forms only the dorsal tip of the pit.</p> <p>The cheek in THUg 3338 is not well preserved. The jugal lies at the posteroventral corner of the orbital margin, and this part of the jugal is well preserved, particularly on the right side. As in other Bothremydini, it lies between the postorbital and maxilla. The cheek in other Bothremydini is not preserved either. It is missing in Bothremys cooki and Zolhafah. It is preserved in B. maghrebiana, but the jugal-quadratojugal sutures are indistinct. In Rosasia the jugal contacts the quadratojugal and not the quadrate, being placed relatively high in the cheek. In Araiochelys the jugal is small, as in the other Bothremydini, and may not have contacted the quadrate. The extent of the cheek in Araiochelys can be restored, showing that the jugal was probably separated from the cheek margin by a quadrate-maxilla contact, as in B. maghrebiana and Rosasia.</p> <p>[M. Stalcup and F. Ippolito, del.]</p> <p>QUADRATOJUGAL (figs. 122, 125)</p> <p>Preservation: The quadratojugal in THUg 3338 is poorly preserved. It is missing on the left side and indistinct on the right. What appears to be the quadratojugal-postorbital suture is in an area of minute breakage, but the quadrate-quadratojugal suture is clear.</p> <p>Contacts and structures: The quadratojugal is a long flat element as interpreted here, with an exposure posteriorly on the temporal emargination between the postorbital and quadrate. The medial contact with the postorbital runs slightly laterally as it extends anteriorly. The quadrate contact is the usual curved suture roughly paralleling the cavum tympani. The anterior contact of the quadratojugal is missing, but it may have contacted the jugal and maxilla, as in Rosasia. The quadratojugal did not extend ventrally to reach the cheek margin as in Foxemys and Polysternon, due to the quadrate-maxilla contact (see Quadrate).</p> <p>SQUAMOSAL (figs. 122, 125)</p> <p>Preservation: The squamosals in THUg 3338 are present on both sides, but the edges have been damaged. The left one is more complete, but it is supported by matrix ventrally and has some missing areas dorsally.</p> <p>Contacts: The squamosal contacts in Araiochelys are the same as in Bothremys maghrebiana, as far as can be determined.</p> <p>Structures: The squamosal in Araiochelys agrees closely with that bone in Bothremys maghrebiana. Unfortunately, complete squamosals are rare in the tribe Bothremydini; B. cooki has none, and squamosals are missing posteriorly in Zolhafah, Rosasia, and Chedighaii hutchisoni. In B. maghrebiana and Chedighaii barberi, the squamosal has a posterior process that has a low ridge ventrally and a low trough on its dorsal surface, nearly identical to the squamosal of Araiochelys.</p> <p>POSTORBITAL (figs. 122, 125)</p> <p>Preservation: The postorbital is nearly complete on the right side of THUg 3338, but only its anterior end is present on the left side.</p> <p>Contacts and structures: As in Bothremys maghrebiana, the lateral plate of the postorbital of Araiochelys contacts the frontal anteromedially, the jugal anterolaterally, the quadratojugal posterolaterally, and the parietal medially. The medial process of the postorbital is mostly covered by matrix in THUg 3338, but the jugal contact can be seen in the anterior wall of the fossa temporalis inferior.</p> <p>PREMAXILLA (figs. 122–125)</p> <p>Preservation: Both premaxillae are present and well preserved with clear sutures in THUg 3338.</p> <p>Contacts: The premaxilla of Araiochelys contacts the maxilla posterolaterally, the other premaxilla on the midline, and the vomer posteriorly.</p> <p>Structures in dorsal view: The premaxilla forms the anterior part of the fossa nasalis and apertura narium externa. In Araiochelys the fossa and apertura are relatively large, as in Bothremys and Chedighaii and in contrast to the smaller apertura and fossa in Foxemys and Rosasia. The orientation of the opening is more lateral in Araiochelys than in the other members of the Bothremydini. Araiochelys also differs in having a completely divided or almost completely divided apertura rather than the partially divided or figure eight-shaped apertura in Bothremys cooki and Chedighaii. Each premaxilla in Araiochelys has a dorsal process adjacent to the midline that together form the lower part of the nasal division. The base of the process is thick and is similar to the lower dorsal process in Bothremys maghrebiana. Both Chedighaii and B. cooki are damaged or lack a premaxilla. However, B. cooki has enough of the premaxilla preserved to show that some midline process was present, although its extent is not determinable. The premaxillary dorsal process in Araiochelys is continuous with a posterior midline ridge on the floor of the fossa nasalis. A similar, but lower ridge is present in B. maghrebiana and probably B. cooki. The anterior margin of the premaxilla in Araiochelys protrudes well anteriorly to the prefrontal in dorsal view, as in Bothremys and Chedighaii but in contrast to Rosasia and Foxemys.</p> <p>Structures in ventral view: The premaxilla forms the anteromedial part of the triturating surface and consists of a more vertical labial ridge with a more horizontal plate posteriorly. In Araiochelys the labial ridge has a slight median upturn to form a shallow notch similar to Bothremys but in contrast to Foxemys. Chedighaii is not preserved in this area, although C. barberi shows a ventral curve on the portion of premaxilla preserved. The labial ridge in Araiochelys has a sharp edge but a broad base, as in Bothremys. However, the labial ridge is thinner and has a more acute angle in Araiochelys than in Bothremys.</p> <p>The premaxillary triturating surface behind the labial ridge in Araiochelys forms a relatively deep midline concavity, similar to that in Bothremys but slightly narrower. The lingual ridge forms the anterior and lateral margin of the concavity and marks the edge of the foramina-rich triturating surface. The ridge is higher and more distinct in Araiochelys and Bothremys maghrebiana than it is in B. cooki, which has a low ridge and shallow midline concavity. The premaxilla in Araiochelys forms all of the foramen praepalatinum, which lies in the midline concavity near the vomer suture, as in Bothremys.</p> <p>MAXILLA (figs. 122–125)</p> <p>Preservation: Both maxillae are present in THUg 3338. They are complete and well preserved except for the posterolateral limits on the cheek, which are represented by broken edges on both maxillae.</p> <p>Contacts: The maxilla contacts in Araiochelys for both the vertical and horizontal plates are the same in Araiochelys and Bothremys except for the area around the triturating surface pit. In Araiochelys and Bothremys cooki there is no maxilla-palatine contact posterior to the pit, while in Bothremys maghrebiana there is a contact. On the cheek, there is no posterior contact of the maxilla with anything as preserved. However, on the right side the quadrate has a long anterior process with a broken anterior margin that nearly reaches the maxilla with a broken posterior margin. It is very difficult to see how any of the other cheek elements could have extended between the quadrate and maxilla to separate them. It is possible that a narrow space was present between them, but this seems unlikely, and the restoration has been done with a quadrate-maxilla contact as in Bothremys maghrebiana.</p> <p>Structures of vertical plate: The dorsal process of the maxilla is wider in Bothremys and narrower in Araiochelys and Chedighaii. For Araiochelys this is a function of the large apertura narium externa, while in Chedighaii the orbits are closer to the apertura.</p> <p>The maxilla forms the lower margin of the fossa orbitalis, and in most bothremydids this is a narrow ridge. In Bothremys this ridge is either absent (B. cooki and B. maghrebiana AMNH 30561) or very low (B. maghrebiana AMNH 30041, AMNH 30522, MHNL 20- 268370, and AMNH 30234). In Araiochelys it is a distinct raised ridge clearly separating cheek from fossa orbitalis. The fossa orbitalis itself is comparatively larger and faces more laterally in Araiochelys than in Bothremys and Chedighaii.</p> <p>The vertical plate of the maxilla forms the suborbital part of the cheek and the labial ridge. In dorsal view the external surface of this plate is a nearly straight, more vertical sheet in Araiochelys. In Bothremys the maxilla is convex anterolaterally, forming a curved margin. The degree of swelling is greater in Bothremys than in any of the other bothremydids. However, the two species of Chedighaii have expanded maxillae, with C. barberi being relatively straight, although the skull is wide in contrast to Araiochelys. In C. hutchisoni the maxilla edge is broken and it may have been curved. The maxillary plate below the orbit is unusually deep in Bothremys and Chedighaii, but in Araiochelys it is shallower.</p> <p>The labial ridge in Araiochelys is acute along its edge, as in Bothremys and Chedighaii barberi (missing in C. hutchisoni), but in Bothremys the bone thickens dorsally more than in Araiochelys. The entire maxillary plate in Bothremys is thicker than in Araiochelys. Chedighaii hutchisoni is thick, as in Bothremys, but C. barberi is thinner, as in Araiochelys.</p> <p>Structures of horizontal plate of maxilla: The maxilla of Araiochelys is relatively narrow compared to Bothremys and Chedighaii hutchisoni (fig. 123). The shape is not as triangular as in the other Bothremydini. The apertura narium interna is slightly narrower in Araiochelys than in Bothremys maghrebiana, but not as narrow as in B. cooki. The apertura in both Araiochelys and B. maghrebiana is larger than in B. cooki.</p> <p>The triturating surface of Araiochelys is defined medially by a low lingual ridge. In common with Bothremys but in contrast to Chedighaii, there is a well-developed pit in the posterior part of the triturating surface. The maxilla forms the anterior and lateral cone-shaped surface that forms the outer part of the pit; the tip is formed by the jugal (see Jugal). This part of the maxilla in Araiochelys, the area between the pit and the labial ridge, is much narrower than in Bothremys. The differences in this part of the triturating surfaces between Araiochelys and Bothremys might be compared with differences found between males and females in Graptemys (Lindeman, 2000), Emydura (Cann, 1998), and trionychids (Dalrymple, 1977) (see Discussion in Systematics). In Bothremys there is also an expansion of the palatine part of the triturating surface medial to the pit. The more anterior part of the triturating surface in Araiochelys has a low lingual ridge medial to a shallow trough.</p> <p>Most of the dorsal surface of the maxilla is covered by matrix, but some is visible in the floor of the right fossa orbitalis. The maxilla only forms a narrow part of the fossa, lateral to the palatine.</p> <p>VOMER (figs. 122–125)</p> <p>Preservation: The vomer in THUg 3338 is nearly complete; the posterior contact with the palatines is damaged.</p> <p>Contacts: The vomer contacts in Araiochelys are as in Bothremys: premaxilla anteriorly, maxilla anterolaterally, and palatine posteriorly. Chedighaii hutchisoni lacks the maxilla contact. The anterior end has a short maxilla contact, as in B. maghrebiana, rather than the long one in B. cooki.</p> <p>Structures: The vomer in Araiochelys is dumbbell shaped as in Bothremys. Only its ventral surface is visible. The vomer separates the paired apertura narium interna, as in Bothremys and Chedighaii (see Maxilla).</p> <p>PALATINE (figs. 122–125)</p> <p>Preservation: Both palatines are present in THUg 3338. They are only damaged where they form the posterior margin of the apertura narium interna, and only a small amount of bone seems to be missing. Only the ventral surface of the palatine is visible.</p> <p>Contacts: The contacts of the palatine in Araiochelys are the usual bothremydid ones: maxilla anteriorly, vomer anteromedially, palatine medially, and pterygoid posteriorly. In addition, Araiochelys has a lateral jugal contact beginning in the triturating surface pit and extending posteriorly to the usual palatine-jugal contact. In contrast to Bothremys maghrebiana, there is no palatine-maxilla contact posterior to the pit (see Maxilla, Jugal).</p> <p>Structures on ventral surface (dorsal surface obscured by matrix): The triturating surface in Araiochelys has a significant contribution from the palatine, which forms the posteromedial part of the surface and the posterior part of the lingual ridge (see Maxilla). This portion of the palatine is narrower in Araiochelys than in Bothremys and Chedighaii. The palatine forms the posterior and posterolateral margins of the apertura narium interna. It is very similar in Araiochelys and Bothremys maghrebiana. The foramen palatinum posterius is formed by both palatine and pterygoid, as in Bothremys and Chedighaii. The degree of palatal arching and choanal formation is very similar in Araiochelys, Bothremys, and Chedighaii.</p> <p>QUADRATE (figs. 122, 125, 126)</p> <p>Preservation: Both quadrates are present in THUg 3338, but both are incomplete on their anterior margins in the cheek. Both have also been crushed slightly dorsoventrally.</p> <p>Contacts in lateral view: The quadrate in Araiochelys contacts the squamosal posterolaterally, as in the other Bothremydini. There is probably a quadrate-maxilla contact on the cheek (see Maxilla) on the right side, as seen in Bothremys. Anterodorsally the postorbital contacts the quadrate but the suture in unclear (see Postorbital). Although unlikely, a jugal contact is possible due to the poor condition of the cheek in THUg 3338 (see Jugal). The dorsal margin of the quadrate is a broken edge on both sides in THUg 3338, so that the presence or absence of a squamosal-quadratojugal contact is indeterminate. Thus, the exposure of the quadrate on the temporal emargination as it is preserved is unlikely to have been its original condition.</p> <p>Structures in lateral view: The cavum tympani in Araiochelys is similar to that in Bothremys maghrebiana. The incisura columellae auris is completely closed, as in other taxa in the subtribe Bothremydina, and the stapes lies in a bony canal. As in B. maghrebiana, Araiochelys has a low ridge extending posteriorly from the incisura to the sulcus eustachii. The sulcus is a deep cleft in Araiochelys and Bothremys (it is not well preserved in Chedighaii) with a lateral overhang made up of quadrate and squamosal and a ventrolateral shelf formed by the quadrate. The antrum postoticum in Araiochelys is very similar to that in B. maghrebiana, although there is some variation in size of the antrum among the four specimens of that species. The antrum postoticum of Araiochelys faces anterolaterally, as in B. maghrebiana, and it is about the same size as in AMNH 30561, a little larger than in AMNH 30234, and smaller than in AMNH 30041.</p> <p>The cavum tympani in Araiochelys is a deep cone, becoming shallower anteriorly, with a large lateral shelf ventrally, all as in Bothremys (it is not completely preserved in Chedighaii). The cavum in THUg 3338 is partly distorted by dorsoventral crushing so that the shelf now forms a pocket at the bottom of the cavum tympani, but this pocket is due to crushing, and the shelf was like that in Bothremys maghrebiana (AMNH 30041). There is no fossa precolumellaris.</p> <p>Contacts and structures in dorsal view: In Araiochelys the quadrate contacts in dorsal view on the otic chamber are as in the other Bothremydini (except for Zolhafah): prootic anteromedially, opisthotic posteromedially, supraoccipital medially, and squamosal posteriorly. The foramen stapedio-temporale lies on the anterior face of the otic chamber and, as in other Bothremydini, is not visible in dorsal view.</p> <p>Contacts in ventral and posterior view: As in the other Bothremydidae, Araiochelys has these contacts: pterygoid anteromedially, basisphenoid medially, basioccipital posteromedially, exoccipital posteromedially behind the basioccipital, and squamosal posterolaterally.</p> <p>Structures in ventral and posterior view: The foramen posterius canalis carotici interni in Araiochelys is formed in the pterygoid-quadrate suture, as in Bothremys and Chedighaii. As in those genera, the quadrate forms more of the foramen and has an anteromedially trending trough that leads into the foramen.</p> <p>The fenestra postotica in Araiochelys is an oval opening (fig. 126), separated laterally from the foramen jugulare posterius by a broad sheet of quadrate, exoccipital, and opisthotic, as in Bothremys and Chedighaii. The fenestra postotica is not divided but is figure eight-shaped with a more ventrolateral channel and a more dorsomedial one. The opisthotic forms the dorsomedial part of the fenestra postotica.</p> <p>On the posterior surface of the processus articularis of the quadrate is a posteriorly directed ridge or flange running roughly horizontally (‘‘quadrate pocket’’ in fig. 126). This flange is downturned along its posterior margin to enclose a trough or pocket on the back of the quadrate. This area is the attachment for the M. depressor mandibulae in other turtles, so presumably this pocket contained at least part of the attachment for this muscle. Bothremys maghrebiana and Chedighaii barberi both have a distinct ridge in this position, but not the downturned edge making it a partially enclosed pocket. B. cooki and C. hutchisoni lack this area, and AMNH 29444, B. cooki, has the same ridge as in C. barberi. In the roof of this quadrate pocket in Araiochelys is the posterior opening for the chorda tympani, the foramen chorda tympani inferius, completely hidden in posterior view as well as in the oblique view of the ear.</p> <p>The internal cavum acustico-jugulare and aditus canalis stapedio temporalis are not visible due to matrix. The condylus mandibularis is slightly anterior to the condylus occipitalis, as in Bothremys and Chedighaii; it is not anterior to the main body of the basisphenoid, as in Polysternon.</p> <p>PTERYGOID (figs. 122–125)</p> <p>Preservation: Both pterygoids are present in THUg 3338 with the dorsal and most of the lateral surfaces covered by matrix. Only the proximal part of the pterygoid flange remains, but all (left) and nearly all (right) of the processus trochlearis pterygoidei are present.</p> <p>Contacts in ventral view: Araiochelys has the usual contacts of the Bothremydini: palatine anteriorly, pterygoid anteromedially, basisphenoid posteromedially, and quadrate posterolaterally. Araiochelys lacks the pterygoid-maxilla contact posterior to the triturating pit seen in B. maghrebiana, also present in the other Bothremys species. Nearly all of the dorsal and lateral surfaces of the pterygoid are covered by matrix in THUg 3338, but at the base of the processus trochlearis pterygoidei in the postorbital wall can be seen the jugal and postorbital contacts of the pterygoid.</p> <p>Structures on ventral surface: The pterygoid in Araiochelys is very similar to that in Bothremys. The processus trochlearis pterygoidei is well preserved in Araiochelys and agrees closely with that in Bothremys. The quadrate ramus bears the pterygoid flange (preserved only in B. maghrebiana). There is no fossa pterygoidea in Araiochelys, Bothremys, or Chedighaii as occurs in Foxemys and Polysternon. The foramen posterius canalis carotici interni has the pterygoid forming its anterior edge, as in Bothremys and Chedighaii (see Quadrate). The foramen palatinum posterius is formed by palatine and pterygoid (see Palatine). The pterygoid of Araiochelys has a narrow ridge paralleling the pterygoid-basisphenoid suture. This is seen in B. maghrebiana but not in Chedighaii or B. cooki.</p> <p>SUPRAOCCIPITAL (figs. 122, 125)</p> <p>Preservation: ThesupraoccipitalinTHUg 3338 is complete and not obscured by matrix.</p> <p>Contacts: As in the other Bothremydini, the supraoccipital of Araiochelys contacts are parietals anterodorsally, the prootic anterolaterally, the quadrate laterally, the opisthotic posterolaterally, and the exoccipital posteroventrally. These contacts in Araiochelys are very similar to those in Bothremys and Chedighaii.</p> <p>Structures: The crista supraoccipitalis in Araiochelys is short and relatively shallow, similar to that in Bothremys maghrebiana and Chedighaii hutchisoni. In Araiochelys, howev- er, the ventral margin of the crista is thin, while in Bothremys and Chedighaii there is a swelling along its ventral edge that is thicker than the plate itself. As in everything, the supraoccipital forms the top of the foramen magnum.</p> <p>EXOCCIPITAL (figs. 122, 125, 126)</p> <p>Preservation: Both exoccipitals in THUg 3338 are preserved and are complete with the sutures clear.</p> <p>Contacts: As in the other Bothremydini, the exoccipital of Araiochelys contacts the supraoccipital dorsally, the opisthotic laterally, the quadrate ventrolaterally, and the basioccipital ventrally.</p> <p>Structures: The foramen magnum and condylus occipitalis are very similar in Araiochelys and Bothremys maghrebiana (missing in B. cooki). The condyle is formed entirely by exoccipital, with the basioccipital not even entering the neck of the condyle.</p> <p>The foramen nervi hypoglossi are nearly the same in position in Araiochelys, Chedighaii, Bothremys maghrebiana, and B. cooki (AMNH 29444). Two foramina are present, with the medial one being larger and more dorsal and the lateral one being smaller and more ventral. The foramen jugulare posterius is also very similar in the three genera, except that it is larger in AMNH 29444 than in Araiochelys, B. maghrebiana, and Chedighaii. The foramen is completely closed, with the exoccipital being prevented from meeting itself by a small process of opisthotic. Above the foramen jugulare posterius, the exoccipital forms the medial portion of an overhanging ridge, similar to that in Bothremys maghrebiana but much larger (see Opisthotic).</p> <p>BASIOCCIPITAL (figs. 122, 125, 126)</p> <p>Preservation: The basioccipital in THUg 3338 is complete with clear sutures. Only its ventral surface is visible.</p> <p>Contacts: As in the other Bothremydini, the contacts of the basioccipital in Araiochelys are the basisphenoid anteriorly, the quadrate laterally, and the exoccipitals dorsally.</p> <p>Structures: The condylus occipitalis completely excludes the basioccipital, which has only a small process at the exoccipital median suture. There is a low, blunt tuberculum basioccipitale in Araiochelys, as in Bothremys maghrebiana, AMNH 29444, and Chedighaii. Also as in these taxa, Araiochelys has a shallow median concavity ahead of the condylus occipitalis. The basioccipital in Araiochelys is very short and wide, as in Bothremys and Chedighaii.</p> <p>PROOTIC (figs. 122, 125)</p> <p>Preservation: Both prootics are presumably present and complete in THUg 3338 but are mostly covered by matrix. Both are visible in dorsal view, and the right one has its anterior surface exposed.</p> <p>Contacts: As exposed, the prootic in Araiochelys contacts the quadrate laterally, the parietal medially, and the supraoccipital posterodorsally, all as in Bothremys and Chedighaii. All three lack a prootic-opisthotic contact.</p> <p>Structures: Few prootic structures are visible. The foramen stapedio-temporale lies on the anterior surface of the prootic, but the medial margin and the foramen nervi trigemini are covered by matrix. No internal surfaces are visible.</p> <p>OPISTHOTIC (figs. 122, 125, 126)</p> <p>Preservation: Both opisthotics are present in THUg 3338 and are complete with most sutures clear, although the most lateral sutures are difficult to make out.</p> <p>Contacts: As in the other Bothremydini, the opisthotic of Araiochelys contacts are the supraoccipital anteromedially, the quadrate anterolaterally, the squamosal posterolaterally, and the exoccipital posteromedially. There is no prootic contact.</p> <p>Structures: The opisthotic barely enters the margin of the foramen jugulare posterius (see Exoccipital). The opisthotic forms the dorsomedial part of the fenestra postotica (see Quadrate). In Araiochelys, the opisthotic and exoccipital form an overhanging ridge above the foramen jugulare posterius and fenestra postotica. This ridge appears to be the same as that seen in Chedighaii hutchisoni (broken in C. barberi) and Bothremys.</p> <p>BASISPHENOID (figs. 122–125)</p> <p>Preservation: The basisphenoid in THUg 3338 is complete with clear sutures; only its ventral surface is visible.</p> <p>Contacts: As in the other Bothremydini, the basisphenoid of Araiochelys contacts are the pterygoids anteriorly, the quadrate laterally, and the basioccipital posteriorly. As in Bothremys maghrebiana, B. cooki (AMNH 29444), and Chedighaii, the pterygoid contact is long and the quadrate contact very short.</p> <p>Structures: The basisphenoid in Araiochelys is totally flat and featureless.</p> <p>Bothremys cooki</p> <p>The skull of Bothremys cooki is the original bothremydid skull from the (probably) Late Cretaceous of New Jersey that was first described by Leidy (1865) (see fig. 19). It lacks the otic chambers and the occiput, but the remaining areas are well preserved, free of matrix, with visible internal areas. The basisphenoid is separate and its dorsal surface is visible. An otic chamber from North Carolina (AMNH 29444) is referred to this species, although there is only a very slight morphologic overlap, the size agrees, and it belongs in this group. The otic chamber is described and figured in this section but it is not used in the reconstructions except for the additional side view (fig. 127D). The skull of Bothremys cooki was described in detail in Gaffney and Zangerl (1968), in the senior author’s first paper. I hope I get it right this time.</p> <p>PREFRONTAL (figs. 127, 130)</p> <p>Preservation: The right prefrontal is nearly complete; the left one is missing its anterior portion.</p> <p>Contacts: The prefrontal in Bothremys cooki has the usual Bothremydini contacts: the maxilla anteroventrolaterally, the other prefrontal medially, and the frontal posteriorly. There is no anteroventral contact with the premaxilla as in Araiochelys and B. kellyi. The ventral process of the prefrontal has a broad contact with the palatine in the orbital floor. The dorsal process of the maxilla extends anteromedially to restrict the exposure of the prefrontal in B. cooki and B. maghrebiana.</p> <p>Structures: The dorsal margin of the apertura narium externa has the midline protrusion or process seen in the other Bothremys species and most bothremydids. The interorbital distance in Bothremys cooki is less than in B. kellyi and about the same as in B. maghrebiana.</p> <p>FRONTAL (figs. 127, 130)</p> <p>Preservation: Both frontals are present and nearly complete.</p> <p>Contacts: As in the other Bothremys, the frontal of B. cooki contacts the prefrontal anteriorly, the parietal posteriorly, the postorbital posterolaterally, and the other frontal medially. The frontal in B. cooki is slight longer and slightly narrower than in B. maghrebiana, but it is very similar to B. kellyi.</p> <p>Structures: The frontal in Bothremys is only narrowly exposed in the orbital margin, in contrast to Rosasia and Zolhafah, although the degree of exposure is only slightly less than in Araiochelys, Polysternon, and Foxemys. The sulcus olfactorius (see Gaffney and Zangerl, 1968: fig. 21, for endocast) is similar in all Bothremys and is lower and wider than in forms like Galianemys.</p> <p>PARIETAL (figs. 127, 130)</p> <p>Preservation: Both parietals are present, but they lack the entire posterolateral emargination. The processus inferior parietalis is present and visible internally and externally on both sides of the skull. The right one is nearly complete, but both parietals have some breakage along their lower margins.</p> <p>Contacts of dorsal plate: As in B. maghrebiana. The ventral process of the parietal lateral to the sulcus palatinopterygoideus (fig. 278B) contacts the postorbital laterally and probably the pterygoid ventrally. Although the contact is missing, the space would have been filled by the parietal.</p> <p>Structures of dorsal plate: The degree of temporal emargination is not determinable in B. cooki. The ventral process of the parietal that forms the roof for the sulcus palatinopterygoideus is unusually deep in the other species of Bothremys, and this is apparent in B. cooki, resulting in a low sulcus palatinopterygoideus. The parietal has a ventrolateral process lateral to the sulcus palatinopterygoideus that descends alongside the postorbital. The ventral end of the process is broken off on both sides, but on the right side the pterygoid has a suture as its dorsal margin, and only the parietal would have filled the space and reached the pterygoid (Gaffney and Zangerl, 1968: 211, fig. 13). This process and contact also occur in Chedighaii hutchisoni, Bothremys maghrebiana, and Bothremys arabicus.</p> <p>Contacts of processus inferior parietalis: The processus contacts the palatine anteroventrally, the pterygoid ventrally, the prootic posteroventrally, and the supraoccipital posteriorly, as in other bothremydids.</p> <p>Structures of processus inferior parietalis: The foramen interorbitale is low in Bothremys cooki, as it is in B. maghrebiana (fig. 144), Chedighaii hutchisoni, Araiochelys, Rosasia, and Foxemys. The foramen nervi trigemini has the usual bones forming it: parietal anterodorsally, prootic dorsolaterally, and pterygoid ventrally.</p> <p>JUGAL (figs. 127, 128, 130, 133)</p> <p>Preservation: The jugal is present and missing its posterior margin on both sides.</p> <p>Contacts of lateral plate: The jugal plate in Bothremys cooki contacts the maxilla anteroventrally in a long, interdigitating suture. The postorbital contact is along the upper edge of the jugal, but the postorbital sends a small process ventrally along the anterodorsal margin of the jugal in the orbital rim. The ventral edge of the jugal entirely contacts the maxilla. The posterior edge is broken, so the contact is indeterminate.</p> <p>Structures of lateral plate: The jugal forms a small part of the orbital margin, less of it in Bothremys cooki than in B. maghrebiana and B. kellyi. B. cooki has a low ridge but no acute rim marking the ventral orbital margin. This is the condition in B. maghrebiana also, but both B. kellyi and Bothremys arabicus have a distinct rim with an acute ridge.</p> <p>Contacts of medial process: On the ventral surface, the jugal in B. cooki is broadly exposed on the triturating surface, contacting the maxilla anteriorly, the palatine medially, and the pterygoid posteromedially. The broad pterygoid contact on the ventral surface is unique to B. cooki. The jugal in B. maghrebiana has a much smaller exposure; the palatine-maxilla contact prevents jugal exposure along the fossa temporalis margin as seen in many other Bothremydini.</p> <p>The postorbital wall in posterior view shows the jugal forming its lower half, contacting the postorbital dorsally and the pterygoid medially. The postorbital wall in anterior view shows less jugal, as it lies primarily in the fossa orbitalis floor, contacting the postorbital dorsally and the palatine medially.</p> <p>Structures of medial process: The jugal in Bothremys cooki is unique among bothremydids in its extensive exposure on the palate (figs. 128, 133). It forms most of the characteristic pit and extends posteromedially, forming most of the wall between the fossa temporalis and the pit (Gaffney and Zangerl, 1968: fig. 20). As in the other pitted bothremydids, the jugal forms the roof of the pit and is exposed on the dorsal surface near the orbit directly above the pit, as in the nonpitted forms. So the pit development does not involve the relative movement of the jugal onto the triturating surface, it perchance is the result of exposure of the overlying jugal by removal of maxilla and palatine.</p> <p>QUADRATOJUGAL Preservation: Not preserved.</p> <p>SQUAMOSAL Preservation: Not preserved.</p> <p>POSTORBITAL (figs. 127, 130)</p> <p>Preservation: The anterior part of both postorbitals are present, but the posterior part of the lateral plates that make up the temporal roof are gone.</p> <p>Contacts of lateral plate: The postorbital contacts the jugal anteroventrally, the frontal anteromedially, and the parietal posteromedially, as in the other Bothremys species. The jugal contact has a narrow, anteroventral process that extends along the orbital margin, not seen in other Bothremydini.</p> <p>Structures of lateral plate: The postorbital in B. cooki forms more of the orbital margin than in B. maghrebiana and B. kellyi, comparable to that in Rosasia.</p> <p>Contacts of medial process: In the posterior wall of the fossa orbitalis, the postorbital of B. cooki contacts the palatine anteromedially, the jugal anterolaterally, and the parietal medially, as in B. maghrebiana. In the anterior wall of the fossa temporalis, the postorbital contacts the jugal ventrolaterally, the parietal medially, the maxilla ventrally, and the pterygoid ventromedially. There does not appear to be a palatine contact as in B. maghrebiana.</p> <p>Structures of medial process: The medial postorbital process in B. cooki forms part of the roof and lateral wall of the sulcus palatinopterygoideus (fig. 279B), which in Bothremys and Chedighaii is lower than in other Bothremydini. The posteroventral part of the fossa orbitalis is enlarged in Bothremys, Chedighaii, Araiochelys, and Rosasia, in contrast to remaining Bothremydini.</p> <p>PREMAXILLA (figs. 127, 128, 130)</p> <p>Preservation: Parts of both premaxillae are present in AMNH 2521. The right one is nearly complete except for an area missing along the midline suture. The left one is missing more of the medial area.</p> <p>Contacts: As in Bothremys maghrebiana.</p> <p>Structures on dorsal surface: The fossa nasalis and apertura narium externa in B.</p> <p>cooki are very similar to those in B. maghrebiana. Although not completely preserved, the premaxilla in B. cooki has a dorsal process partially dividing the apertura, as in B. maghrebiana. The anterior surface of the premaxilla slopes anterodorsally in both so that the rim of the apertura narium externa is anterior to the labial ridge. The ventral margin of the apertura is also well anterior to the prefrontal as well.</p> <p>Structures on ventral surface: The labial ridge in Bothremys cooki is very similar to that in B. maghrebiana. It is blunt, not as blunt as in Zolhafah, but more obtuse than the acute ridge of Foxemys. Actually, all of this crap is pretty obtuse in my opinion. The labial ridge in B. kellyi is slightly thicker than in B. cooki and B. maghrebiana; the ridge is not preserved in Bothremys arabicus. The snout of B. cooki is slightly pinched, as it is in B. kellyi, B. maghrebiana, Rosasia, Polysternon, and Foxemys.</p> <p>The midline concavity formed by the lingual ridge on the palate is very similar in both B. cooki and B. maghrebiana. It is shallower in B. cooki than in B. maghrebiana. The concavity is narrower in these two species, along with Rosasia and Araiochelys (and probably Chedighaii barberi), in contrast to the other Bothremydini. The foramen praepalatinum is close to and may be within Contacts of vertical plate: The maxilla the premaxilla-vomer suture. contacts the premaxilla anteromedially, the jugal posterodorsally, and the prefrontal MAXILLA (figs. 127, 128, 130, 133) anterodorsally. The quadrate and quadrato- Preservation: Both maxillae are present jugal contacts are not determinable.</p> <p>in AMNH 2521, and they are complete Structures of vertical plate: The maxilla except for their posterolateral margins, which forms the lower margin of the orbit, which in are broken edges. Bothremys cooki and B. maghrebiana is a low,</p> <p>rounded surface, not an acute ridge, as in B. kellyi. The fossa nasalis and choanal passages in B. cooki are the same size and shape as in B. maghrebiana. There is no indication of a cheek emargination. B. cooki differs slightly from both B. maghrebiana and B. kellyi in having a slightly deeper maxilla below the orbit. The dorsal process of the maxilla is broad in B. cooki, B. maghrebiana, B. kellyi, and probably Bothremys arabicus, in contrast to the narrower process in other Bothremydini.</p> <p>Contacts of horizontal plate: The maxilla contacts the premaxilla anteromedially, the vomer medially, the palatine posteromedially, and the jugal posterolaterally. There is no midline contact of the maxillae. Bothremys cooki differs from B. maghrebiana in lacking a maxilla-palatine contact posterior to the jugal. The vomer-maxilla contact is much wider in B. cooki than in B. maghrebiana.</p> <p>Structures of the horizontal plate: The maxilla of B. cooki is dominated by the large pit formed by maxilla, jugal, and palatine (fig. 133). Nearly all of the triturating surface is sloping into the pit, as in B. maghrebiana, B. kellyi, and Bothremys arabicus, in contrast to Araiochelys, in which the anterior part of the surface is flat or slopes away from the pit. The dorsal surface of the horizontal plate forms the floor of the fossa orbitalis, as in B. maghrebiana, and part of the postorbital wall.</p> <p>VOMER (figs. 127, 128, 130)</p> <p>Preservation: A nearly complete vomer, possibly missing some of its anterior margin, is preserved in AMNH 2521.</p> <p>Contacts: The vomer contacts the premaxilla anteriorly, the maxilla anterolaterally, and the palatine posteriorly. The maxilla contact is relatively wide, uniquely so among Bothremydini. The vomer has an elongated anterior end followed by a narrow bar separating the apertura narium interna (not the apertura narium externa as stated incorrectly in Gaffney and Zangerl, 1968: 219). Foxemys and Rosasia also have a wide maxilla-vomer contact, but it is short in Araiochelys, Zolhafah, and B. maghrebiana. There does not seem to be a vomer-maxilla contact in Chedighaii hutchisoni.</p> <p>Structures: The vomer is higher than wide in cross section and has a shallow groove, the sulcus vomeri, running along its dorsal surface. The posterior half of the vomer rises dorsally above the level of the median concavity on the palate.</p> <p>PALATINE (figs. 127, 128, 130)</p> <p>Preservation: Both palatines are present. The right one is missing some bone medially, and the left one is damaged along its lateral and ventrolateral edge. Both are damaged posteriorly. This breakage can be seen in the 1865 figures of Leidy (pl. 18. fig. 7; reproduced as fig. 19 in this paper).</p> <p>Contacts: The palatine in Bothremys cooki contacts the maxilla anterolaterally, the jugal laterally, the pterygoid posteriorly, and the vomer anteromedially. The palatine of B. cooki does not contact the maxilla posterior to the pit as it does in B. maghrebiana. In the floor of the fossa orbitalis the palatine contacts the maxilla anteriorly, the jugal laterally, the postorbital posterolaterally, and the pterygoid in the floor of the sulcus palatinopterygoideus.</p> <p>Structures on dorsal surface: The floor of the fossa orbitalis in B. cooki has the posteroventral pocket also seen in Chedighaii and the other Bothremys species. The palatine sends a low process dorsally to meet the anterior part of the processus inferior parietalis and has a dorsal process in the lateral wall of the sulcus palatinopterygoideus that meets the postorbital. The sulcus is continuous with the medial part of the fossa orbitalis.</p> <p>Structures on ventral surface: The palatine forms the posteromedial part of the triturating surface, agreeing with B. maghrebiana and B. kellyi (see B. maghrebiana and B. kellyi for description). The lingual ridge is nearly the same in all three, with nearly all of the triturating surface sloping into the pit. The palatine forms the lateral margin of the apertura narium interna. The apertura in B. cooki is a nearly circular, paired opening, while in B. maghrebiana, the apertura is more elongate and slightly larger. Part of the apertura edges are damaged in B. kellyi. In Bothremys arabicus the apertura is also circular but larger.</p> <p>QUADRATE (figs. 132, 135)</p> <p>Preservation: The quadrate is not known in the type skull, only in AMNH 29444. This otic chamber has most of the quadrate but lacks all of the lateral sutural edges with the cheek bones, as well as some of the anterior cavum tympani. The antrum postoticum is broken open along both quadrate and squamosal, revealing its extent. The medial and ventral parts of the quadrate in AMNH 29444 are complete.</p> <p>Contacts on lateral surface: Only the posterodorsal contact with the squamosal is preserved.</p> <p>Structures on lateral surface: The lateral structures consist of the cavum tympani and associated features and the condylus mandibularis, all of which agree closely with Bothremys maghrebiana. The incisura columellae auris is a canal completely encased by bone, opening at the most medial part of the cavum tympani. The sulcus eustachii is a broad groove extending posteriorly, not a narrow, deep channel as in B. kellyi. The antrum postoticum is slightly larger than in B. maghrebiana, about as large as in B. kellyi.</p> <p>Contacts on dorsal and anterior surface: As in Bothremys maghrebiana.</p> <p>Structures on dorsal and anterior surface: The foramen stapedio-temporale is placed well anterior and medial on the otic chamber, just lateral to the foramen nervi trigemini. The quadrate only enters the ventrolateral part of the foramen stapedio-temporale in AMNH 29444. The anterior surface of the otic chamber is nearly vertical in AMNH 29444, but in Bothremys kellyi the otic chamber is greatly enlarged anteriorly, above the level of the condylus mandibularis. Most of this is formed by quadrate. B. maghrebiana has a slight enlargement, greater than in AMNH 29444, but nothing like that in B. kellyi.</p> <p>Contacts on ventral surface: As in Bothremys maghrebiana.</p> <p>Structures on ventral surface: There is no fossa pterygoidea, although there is a slight depression around the foramen posterius canalis carotici interni. The foramen is formed between the pterygoid and quadrate, as in B. maghrebiana, Araiochelys, and Chedighaii, but in contrast to B. kellyi in which the foramen posterius canalis carotici interni is formed by the basisphenoid as well as pterygoid and quadrate. The condylus occipitalis in AMNH 29444 is nearly on the plane of the condylus occipitalis, as in all the other Bothremydini except Polysternon.</p> <p>Contacts on posterior surface: As in Bothremys maghrebiana.</p> <p>Structures on posterior surface: As in Bothremys maghrebiana except for the bony subdivision of the fenestra postotica in AMNH 29444. The more dorsomedial part, for the stapedial artery, of the fenestra postotica is separated by bone from the more ventrolateral part, for the lateral head vein, in AMNH 29444, in contrast to B. maghrebiana in which they are not separated by bone.</p> <p>PTERYGOID (figs. 127, 128, 130, 132, 134)</p> <p>Preservation: In AMNH 2521, the type skull, parts of both pterygoids are preserved. The left one is more complete; it is missing the quadrate ramus and has breakage along the anterior margin and processus trochlearis pterygoidei. The right one consists only of the medial part and the base of the processus trochlearis pterygoidei. The right otic chamber, AMNH 29444, has the quadrate ramus of the pterygoid preserved.</p> <p>Contacts on ventral surface: The type skull, AMNH 2521, has the pterygoid contacts with the palatine anteriorly, the basisphenoid posteromedially, and the other pterygoid anteromedially. AMNH 29444 shows the quadrate contact.</p> <p>Structures on ventral surface: The processus trochlearis pterygoidei in Bothremys cooki has the same morphology as in B. maghrebiana. The quadrate ramus (AMNH 29444) is also as in B. maghrebiana. There is no fossa pterygoidea (AMNH 29444), but there is a slight depression around the foramen posterius canalis carotici interni. In AMNH 29444, the foramen posterius canalis carotici interni is formed by the pterygoid anteriorly and the quadrate posteriorly, as in B. maghrebiana, B. arabicus, Chedighaii, and Araiochelys, but in contrast to B. kellyi, which has the basisphenoid in the margin. The foramen palatinum posterius in B. cooki is only on the right side and is the same as in B. maghrebiana.</p> <p>Contacts on dorsal surface: The pterygoid at the base of the processus trochlearis pterygoidei contacts the postorbital dorsolaterally, the parietal (see Parietal) dorsomedially, and the jugal dorsolaterally, all as in B. maghrebiana, Chedighaii, and B. arabicus. The crista pterygoidea contacts the processus inferior parietalis dorsally and anteriorly and the prootic posteriorly, as seen in AMNH 2521. In AMNH 29444, the more posterior contacts with the prootic posterodorsally and the quadrate posterolaterally are visible.</p> <p>Structures on dorsal surface: The pterygoid forms the floor of the sulcus palatinopterygoideus, as in the other bothremydids. There is no indication of the foramen nervi vidiani, but this area is not perfectly preserved. The crista pterygoidea is similar in size and shape to that in B. maghrebiana. The foramen nervi trigemini has the usual formation: parietal dorsally, pterygoid ventrally and anteroventrally, and prootic posterodorsally.</p> <p>SUPRAOCCIPITAL (figs. 127, 130, 132)</p> <p>Preservation: Only the anterior part of the supraoccipital is present in the type skull, AMNH 2521. In AMNH 29444 the right lateral process is preserved.</p> <p>Contacts: In AMNH 2521 the supraoccipital contacts the parietals dorsally and anteriorly, as in other bothremydids. It contacts the prootic anterolaterally, but other contacts are lost due to breakage. In AMNH 29444 the supraoccipital contacts the prootic anterolaterally, the quadrate laterally, the opisthotic posterolaterally, and the exoccipital posteroventrally, as in Bothremys maghrebiana.</p> <p>exoccipital is complete except for the ventromedial area and the condylus occipitalis.</p> <p>Contacts: The exoccipital contacts the supraoccipital dorsally, the opisthotic laterally, the quadrate ventrolaterally, and the basioccipital ventrally, all as in B. maghrebiana and other Bothremydini.</p> <p>Structures: The foramen magnum is the same as in B. maghrebiana. The condylus occipitalis is missing, and not enough of it or the basioccipital is preserved to determine the composition of the missing condylus occipitalis. All of the posterior surface of the exoccipital is in the same vertical plane in B. cooki, AMNH 29444, but in B. maghrebiana the lower part is inclined anteroventrally, and in B. kellyi it is concave, similar to Chedighaii hutchisoni.</p> <p>The foramen nervi hypoglossi in AMNH 29444 appear to be three in number, with a large medial one and two small ventrolateral ones, as in Araiochelys and some B. maghrebiana. The foramen jugulare posterius is formed by the exoccipital except laterally, where it is closed by the opisthotic and quadrate. The foramen is relatively large, larger than in B. kellyi, B. maghrebiana, Bothremys arabicus, and Araiochelys, but similar to that in Chedighaii.</p> <p>Structures: The crista supraoccipitalis is represented only by a short broken edge in AMNH 2521, but it agrees with B. maghrebiana. The ventral surface shows only a small part of the foramen magnum and some of the cavum labyrinthicum (see Gaffney and Zangerl, 1968: fig. 16). The other specimen, AMNH 29444, shows most of the foramen magnum on the right side and part of the base of the crista supraoccipitalis. These agree with B. maghrebiana.</p> <p>EXOCCIPITAL (figs. 132, 135)</p> <p>Preservation: The exoccipital is not preserved in the type of Bothremys cooki, AMNH 2521, but it is partially present on the right side of AMNH 29444. This BASIOCCIPITAL (figs. 132, 135)</p> <p>Preservation: The type skull of Bothremys cooki, AMNH 2521, lacks the basioccipital. AMNH 29444 has the right half of one, with the posterior edge having a broken surface.</p> <p>Contacts: The basioccipital in AMNH 29444 contacts the basisphenoid anteriorly, the quadrate laterally, in a contact that is much wider than in B. kellyi and B. maghrebiana, and the exoccipitals posterodorsally.</p> <p>Structures: The condylus occipitalis in AMNH 29444 is broken away, and the broken surface does not allow the extent of the basioccipital to be determined. There is no tuberculum basioccipitale and no ventral median concavity; the ventral surface of the basioccipital is flat. The bone is a bit longer than in the other species of Bothremys.</p> <p>PROOTIC (figs. 132)</p> <p>Preservation: Parts of both prootics are preserved in the type skull of Bothremys</p> <p>The medial surface of the prootic in AMNH 29444 preserves part of the hiatus acusticus and the cavum labyrinthicum. The hiatus has the foramen nervi acustici, which is single as preserved, but the posterior part of the hiatus is missing. The foramen nervi facialis is also preserved.</p> <p>cooki, AMNH 2521. The right one consists of most of the upper part of the bone and its anterior surface. The left one is less preserved laterally and is more damaged by pyrite. The otic chamber, AMNH 29444, has the right prootic nearly complete, lacking only its medial edge.</p> <p>Contacts: The prootic in AMNH 2521 contacts the parietal dorsomedially, and the pterygoid ventrally on its anterior surface. On its dorsal surface it contacts the supraoccipital posterodorsally, but the other contacts are missing. In AMNH 29444, the prootic shows all the contacts seen in Bothremys maghrebiana except for the parietal, which is broken away.</p> <p>Structures: Both prootics show a close similarity to the prootic of B. maghrebiana. They lack the dorsal ridge and strong anterior overlap seen in B. kellyi, Chedighaii, and some B. maghrebiana. The foramen nervi trigemini has the usual formation of parietal anterodorsally, prootic dorsally, and pterygoid posteroventrally. The foramen is preserved in both AMNH 2521 and AMNH 29444, and it is the same size and position in both. In AMNH 29444 the foramen cavernosum lies on the posteroventral margin of the foramen nervi trigemini, showing where the canalis cavernosus becomes the sulcus cavernosus. The foramen nervi trigemini and the foramen stapedio-temporalis are close together, separated only by a narrow bar of prootic.</p> <p>OPISTHOTIC (figs. 132, 135)</p> <p>Preservation: The opisthotic is not preserved in the type of Bothremys cooki, AMNH 2521. A nearly complete right opisthotic is preserved in AMNH 29444. This opisthotic is missing a small part along its posterior edge.</p> <p>Contacts: The opisthotic in AMNH 29444 has the same contacts as in Bothremys maghrebiana.</p> <p>Structures: The foramen jugulare posterius in AMNH 29444 is larger than in most other Bothremydini. It is closed laterally by both opisthotic and quadrate joining to form the margin. The fenestra postotica is completely closed and subdivided by a narrow but complete bony separation into a more dorsomedial foramen for the stapedial artery and a more ventrolateral foramen for the lateral head vein. On the dorsal surface, the opisthotic has a broad, posteriorly facing concavity formed by the opisthotic and squamosal that occurs in B. kellyi and Chedighaii and, to a lesser extent, in most Bothremydini.</p> <p>BASISPHENOID (figs. 127, 130, 134)</p> <p>Preservation: The type skull of Bothremys cooki, AMNH 2521, has most of the basisphenoid preserved, but it is a bit chewed up along its posterior margin. It is also missing some of the posterolateral edges. AMNH 29444 has only the posterolateral third or so of the bone preserved.</p> <p>Contacts on ventral surface: The basisphenoid of B. cooki has the usual contacts as seen in B. maghrebiana. The quadrate contact is narrow, as in B. maghrebiana, but not as narrow as in B. kellyi.</p> <p>Structures on ventral surface: The foramen posterius canalis carotici interni is not formed by the basisphenoid in AMNH 29444, as it is in B. kellyi. The surface is flat, with no concavities or depressions.</p> <p>Contacts on dorsal surface: The dorsal surface is visible in AMNH 2521 (Gaffney and Zangerl, 1968: fig. 19). The crista pterygoidea contacts the processus inferior parietalis, but not the frontal. There is no palatine contact, but the basisphenoid overlaps the pterygoids anteriorly, as in nearly all turtles.</p> <p>Structures on dorsal surface: The rostrum basisphenoidale in Bothremys cooki (fig. 134) is rodlike but fairly short, very similar to that in Chedighaii barberi, YPM PU 12951, an endocast (fig. 167). The dorsum sellae and sella turcica are also very similar, with the dorsum sellae overhanging the sella turcica and forming a teardrop-shaped opening. The foramen anterius canalis carotici interni is visible at the posterolateral corner of the sella turcica. The processus clinoideus is absent, as in Chedighaii (it is indeterminate in the other Bothremys). The foramen nervi abducentis seems to be absent as a fully formed canal, also as in Chedighaii barberi.</p> <p>Bothremys maghrebiana</p> <p>There are five good skulls of Bothremys maghrebiana, making it morphologically the best known taxon in the tribe Bothremydini, and the more extensive description and figures reflect this. There is some individual variation, particularly with MHNL 20- 268370, and this is noted in the description. There are four species in Bothremys at present. B. maghrebiana is most similar to B. cooki, although the analysis only weakly supports a sister-taxon relationship (fig. 288).</p> <p>PREFRONTAL (figs. 136, 143)</p> <p>Preservation: At least parts of the prefrontal are present in all five Bothremys maghrebiana skulls, but it is most complete in AMNH 30041, AMNH 30561, and MHNL 20-268370.</p> <p>Contacts: The prefrontal of Bothremys maghrebiana has the same contacts as in Bothremys cooki and the other bothremydids: maxilla anteroventrolaterally, frontal posteriorly, and other prefrontal medially.</p> <p>Structures: The prefrontal in Bothremys maghrebiana has an anterior projection on the midline that is also present in B. cooki and Chedighaii. In all the Bothremys species this helps form the distinctive figure eight-shaped apertura narium externa. In Chedighaii the lower margin is missing. Foxemys and Polysternon, as well as Cearachelys, have a transverse, not protruding margin to the apertura.</p> <p>The sulcus olfactorius of Bothremys maghrebiana is slightly shallower than in B. cooki and is much shallower than in Chedighaii. It is very variable among the bothremydids.</p> <p>FRONTAL (figs. 136, 143)</p> <p>Preservation: The frontals are preserved in all five Bothremys maghrebiana skulls, although there is some damage to them in both AMNH 30234 and AMNH 30041.</p> <p>Contacts: The frontal in Bothremys maghrebiana has the usual bothremydid contacts: prefrontal anteriorly, postorbital posterolaterally, parietal posteriorly, and frontal medially. The frontal in B. maghrebiana differs from the other bothremydids in being much wider than long. In B. cooki the frontal is nearly square, and in the others the frontal is relatively narrower than in B. maghrebiana.</p> <p>Structures: The size and position of the orbits in the Bothremydini are variable. Bothremys and Chedighaii have unusually small and upward-facing orbits. In Rosasia and Zolhafah the orbits are larger, while in Polysternon and Foxemys the orbits are largest. To a certain extent this size difference is subjective, and Zolhafah has incomplete orbits. Also, the orientation of the orbits is distinctly dorsally facing in Bothremys and Chedighaii hutchisoni. In the other Bothremydidae there is usually a more lateral component to the orbital orientation.</p> <p>PARIETAL (figs. 136, 143, 278B)</p> <p>Preservation: The parietal is present at least in part in all five Bothremys maghrebiana specimens, but its posterior margin is complete only in AMNH 30234 and MHNL 20-268370. In AMNH 30041 the dorsal plate of the right parietal is completely missing, revealing the cavum cranii. AMNH 30234 is probably missing a small part near the midline at its posteriormost limit.</p> <p>Contacts of dorsal plate: As in the other Bothremydinae, the parietal of Bothremys maghrebiana contacts the frontal anteriorly, the postorbital laterally, and the other parietal medially. There is no parietal-quadratojugal or squamosal contact.</p> <p>Structures of dorsal plate: Among the Bothremydini the complete temporal roof is known in Polysternon, Foxemys, Araiochelys, and Chedighaii. The extent of the roof is very similar in Bothremys maghrebiana and Foxemys; it is slightly more extensive than in Polysternon. However, in Chedighaii it is more emarginate than in these three, completely exposing the otic chamber rather than partially exposing it. However, the difference is not great and could very well be within individual variation of some or all of these taxa.</p> <p>The ventral surface of the parietal lateral to the sulcus palatinopterygoideus has a ventral process in Bothremys maghrebiana. In other bothremydids and pleurodires in general the parietal forms the roof of the sulcus, actually a tunnel-shaped structure in most Pelomedusoides, but not part of the lateral wall. In both B. maghrebiana and B. cooki there is a well-developed ventral process attached to the medial edge of the postorbital (fig. 278B). In B. maghrebiana it reaches the palatine (on the anterior surface, not on the posterior surface, which is shown in fig. 278); in B. cooki it is more extensive posteriorly and contacts the pterygoid. The process is best seen in the anterior view of the postorbital wall of the fossa orbitalis in B. maghrebiana, AMNH 30041, and in the posterior view of</p> <p>30234 with additions from AMNH 30041 and AMNH 30561 holotype. [F. Ippolito, del.]</p> <p>the postorbital wall in B. cooki, AMNH 2521.</p> <p>Contacts of processus inferior parietalis: The processus is clearly visible only in AMNH 30041, although its anterior margin is revealed in AMNH 30234. Sutures are clear on the right processus inferior parietalis of AMNH 30041, although there is some fragmentation due to crushing. The contacts are the usual in Bothremydinae: palatine anteroventrally, pterygoid ventrally, prootic posteroventrally, and supraoccipital posteriorly.</p> <p>Processus inferior parietalis: The foramen interorbitale (fig. 144) in Bothremys maghrebiana is nearly the same as in B. cooki, although some crushing in B. maghrebiana makes close comparisons difficult. The foramen is longer in Bothremys (not known in B. kellyi) than in Chedighaii, but it is very similar in Rosasia and Foxemys.</p> <p>The foramen nervi trigemini in B. maghrebiana is formed by the usual bones seen in other Bothremydinae: parietal anterodorsally, prootic dorsolaterally, and pterygoid ventrally. The foramen nervi trigemini in B. maghrebiana is very close to the foramen stapedio-temporale.</p> <p>JUGAL (figs. 136, 137, 139, 143, 278B)</p> <p>Preservation: The jugal is present in all five Bothremys maghrebiana specimens, but it is complete only in AMNH 30234, and sutures are not entirely clear in this skull. Sutures are clear in AMNH 30041 and 30561, which are lacking parts of the lateral plate of the jugal.</p> <p>Contacts of lateral plate: In B. maghrebiana the laterally exposed portion of the jugal contacts the maxilla anteroventrally and the postorbital dorsally. In AMNH 30041 and 30561, which have clear sutures, the jugal ends posteriorly in a broken edge. In AMNH 30234 the sutures are obscured by cracking and poor preservation. It is likely that the quadratojugal-jugal suture lies above the maxilla-quadrate suture and that the jugal does not contact the quadrate. This condition would be nearly the same as in Rosasia. In Chedighaii, Polysternon, and Foxemys there is no maxilla-quadrate contact. In B. cooki and Zolhafah the cheek is missing.</p> <p>Structures of lateral plate: The jugal in Bothremys maghrebiana is exposed in the posterior wall of the orbit and forms part of its margin. There is no cheek emargination in B. maghrebiana, and the jugal does not reach the cheek margin.</p> <p>Contacts of medial process: The orbital floor of Bothremys maghrebiana is best seen in the left orbit of AMNH 30041. The contacts are with the maxilla anteriorly and laterally and with the palatine medially, as in the other Bothremydini. At least some of the jugal is exposed in the orbital floor in all five skulls, but sutures are clearly visible only in AMNH 30041 and 30522. They show contact laterally with the maxilla, ventromedially with the palatine, and dorsomedially with the postorbital. On the triturating surface the jugal contacts the maxilla anteriorly and the palatine posteriorly.</p> <p>Structures of medial process: The jugal is a complex element that forms part of three surfaces. Its dorsal surface forms part of the floor of the fossa orbitalis, and in Bothremys maghrebiana its ventral surface is exposed in the tip of the pit formed on the triturating surface (figs. 136, 137). This condition is best seen in AMNH 30041, on the left side, and in AMNH 30561, also on the left side. The dorsal sutures are clear, but the ventral ones are harder to interpret. However, both AMNH 30561 and AMNH 30041 have the pits broken through by a hole into the orbit that makes identification easier. The bone at the tip of the pit is very thin (as it is in Bothremys cooki) and easily broken. In both skulls the jugal on the dorsal surface can be followed into the broken edge and onto the ventral surface in the pit apex. The sutural contact with maxilla and palatine is irregular in both skulls and obscured by nutrient foramina and fusion, but the general position of the jugal forming the apex of the pit is clear.</p> <p>In Bothremys cooki the pit is formed almost entirely by the jugal, which is broadly exposed along the edge of the fossa temporalis inferior. In Zolhafah and Rosasia much of the pit is also formed by the jugal, which is also exposed along the fossa temporalis inferior margin, although not to the extent seen in B. cooki. Thus, B. maghrebiana differs from all these in having no exposure of the jugal on the margin of the fossa temporalis inferior due to broad contact of the maxilla and palatine. Cearachelys and Galianemys whitei also have exposure of the jugal along this margin, but exposure on the triturating surfaces is slight. In Chedighaii there are no pits and no exposures of the jugal.</p> <p>The third area of jugal exposure is on the posterior surface of the septum orbitotemporale in the fossa temporalis superior (fig. 278B). The jugal here is bound by the maxilla laterally and the postorbital dorsomedially. On the right side of AMNH 30041 the palatine contacts the jugal ventromedially, but on the left side it seems that the palatine does not extend laterally to reach the jugal, although it is not entirely clear. On both sides of this specimen, however, there is a clear ventral suture of the jugal showing that it does not extend anteriorly to meet the jugal exposed in the pit.</p> <p>QUADRATOJUGAL (figs. 136, 141)</p> <p>Preservation: The quadratojugal is missing in AMNH 30041 and 30561. It is present but not clearly defined by sutures in AMNH 30234, AMNH 30522, and MHNL 20- 268370.</p> <p>Contacts: The quadratojugal in Bothremys maghrebiana contacts the quadrate ventrally and the postorbital medially, as seen on the right side of AMNH 30234. On the left side can be seen a narrow, posterolateral contact with the squamosal. The definite maxilla-quadrate contact preserved in AMNH 30561, 30522, and 30041 shows that a C-shaped quadratojugal extending to the cheek margin could not be present in B. maghrebiana. The quadratojugal is restricted to the area above the quadrate, as in Rosasia and B. kellyi. The jugal-quadratojugal suture is not clearly discernable although it is likely in the area posterior to the maxilla-quadrate contact, in which case there would be no quadratojugal-maxilla contact.</p> <p>Structures: The quadratojugal of Bothremys maghrebiana forms part of the temporal roof and is exposed on the edge of the skull roof. There is no cheek exposure of the quadratojugal in B. maghrebiana.</p> <p>SQUAMOSAL (figs. 136, 139)</p> <p>Preservation: The squamosal is present in all five skulls, but it is most complete in AMNH 30234 in which only a small part of the temporal margin seems to be missing. Sutures are visible in all five skulls, but they are best seen in AMNH 30561 and 30041.</p> <p>Contacts: The squamosal contacts the quadrate anteriorly, the opisthotic medially, and the quadratojugal anterodorsally.</p> <p>Structures: The squamosal of Bothremys maghrebiana is a cone-shaped bone fitting around the relatively well-developed antrum postoticum of the quadrate. The bone is not preserved in B. cooki, B. arabicus, and Rosasia, and it is only partially preserved in Chedighaii, Zolhafah, and Polysternon. Foxemys, along with B. maghrebiana, has the best preserved squamosals among the Bothremydini. The bone has a low ventral ridge in all the taxa with it preserved, in contrast to the deep ridge seen in some Taphrosphyini.</p> <p>POSTORBITAL (figs. 136, 141, 278B)</p> <p>Preservation: The anterior part of the postorbital is present in AMNH 30561 and 30041, but only AMNH 30234 has the bone nearly complete. Sutures are clear in AMNH 30561, 30041, and 30234.</p> <p>Contacts of lateral plate: The postorbital of Bothremys maghrebiana contacts the frontal anteromedially, the jugal anteroventrally, the quadratojugal posteroventrally, and the parietal medially.</p> <p>Structures of lateral plate: The postorbital has a wide exposure in the posterior orbital margin in B. maghrebiana, as in the other bothremydines. The postorbital of B. maghrebiana is slightly narrower than that bone in Foxemys, Polysternon, and Chedighaii. It is incomplete or missing in B. cooki, Rosasia, and Zolhafah. The postorbital forms part of the posterior margin of the temporal roof in B. maghrebiana, as in the other Bothremydini.</p> <p>Contacts of medial process: The medial process of the postorbital in Bothremys maghrebiana is preserved in all three skulls but is clearest in AMNH 30041. The postorbital is exposed in the fossa orbitalis and the posterior surface of the postorbital wall (fig. 278B). In the fossa orbitalis the postorbital contacts the jugal laterally, the palatine anteroventrally, and the parietal medially. In B. maghrebiana there is a descending process of the parietal between the postorbital and the sulcus palatinopterygoideus, as in B. cooki. In the posterior view of the postorbital wall the postorbital contacts the jugal laterally, the palatine and maxilla ventrally, the pterygoid medially, and the parietal dorsomedially.</p> <p>Structures of medial process: The postorbital bone in Bothremys maghrebiana makes up part of the roof and lateral wall of the sulcus palatinopterygoideus, as in other pleurodires, but in Bothremys the descending process of the parietal covers much of the postorbital exposure. The postorbital wall in both Bothremys and Rosasia is placed more posteriorly in comparison to other bothremydids. The sulcus palatinopterygoideus (fig. 144) is therefore shorter in Bothremys than in the other bothremydids. The postorbital forms part of the dorsal pocket of the fossa orbitalis, characteristic of bothremydids (character 27).</p> <p>PREMAXILLA (figs. 136, 137, 143)</p> <p>Preservation: At least some of the premaxilla is present in all five Bothremys maghrebiana skulls; sutures are visible in AMNH 30041, 30522, and 30561.</p> <p>Contacts: The premaxilla in B. maghrebiana contacts the maxilla posterolaterally, the other premaxilla medially, and the vomer posteriorly. These contacts are very similar in the other Bothremys species.</p> <p>Structures in dorsal view: The premaxilla in Bothremys maghrebiana is very similar to that in B. cooki. They both are distinctly protuberant, extending anteriorly past the anterior limit of the prefrontal at the dorsal margin of the apertura narium externa. A protuberance of the premaxilla is also present in Rosasia. The condition in Chedighaii and Zolhafah is not determinable.</p> <p>Structures in ventral view: The premaxilla in all species of Bothremys is very wide anteriorly and triangular in shape. This is also the condition in Chedighaii, Rosasia, and Zolhafah, but not in Foxemys, where it is more parallel-sided. In ventral view the premaxilla of Bothremys maghrebiana is very similar to that bone in B. cooki. The labial ridge is blunt but not as blunt as in Zolhafah, and it is more blunt than the acute ridge of Foxemys. All Bothremys species have an anterior profile of the premaxillae with a shallow rise on the midline of the labial ridge, comparable to that in Foxemys, but not flat, as in Kurmademys. All Bothremys species have a similar midline concavity developed on the premaxillae, vomer, and maxillae. This concavity is defined anteriorly and laterally by the lingual ridge and is a surface that lacks the highly vascularized texture of the triturating surface. It is typically distinct and deep in most but not all bothremydids. In B. maghrebiana and B. cooki it is relatively narrow, in contrast to B. kellyi, B. arabicus, Foxemys, and Polysternon. It is much narrower in Rosasia.</p> <p>The foramen praepalatinum is best preserved in Bothremys maghrebiana in AMNH 30561. This paired foramen is almost completely formed by the premaxilla at its posterior limit, close to but not within the vomer-premaxilla suture. It is situated in a very similar position in B. cooki.</p> <p>MAXILLA (figs. 136, 137, 143)</p> <p>Preservation: At least one nearly complete maxilla is present in all five Bothremys maghrebiana specimens. It is best preserved with clearest sutures in AMNH 30561, but good sutures are visible also in AMNH 30041, 30234, and 30522. Only the right maxilla is well preserved in MHNL 20- 268370.</p> <p>Contacts of vertical plate: The more vertical or lateral portion of the maxilla in Bothremys maghrebiana contacts the premaxilla anteromedially, the jugal posterodorsally, the quadrate posteriorly, and the prefrontal anterodorsally. The posterodorsal sutures are not clear in AMNH 30234, which is the only specimen to preserve this area. It is likely that there is a small maxilla-quadratojugal contact as in Rosasia, but this is ambiguous. In common with Rosasia, the maxilla in B. maghrebiana contacts the quadrate posteriorly without the quadratojugal intervening, as in Polysternon, Foxemys, and Chedighaii, among the Bothremydini.</p> <p>Structures of vertical plate: The relations of the dorsal process of the maxilla do not vary much among the Bothremydini. In Bothremys maghrebiana the suture between the maxilla and prefrontal extends from the dorsolateral corner of the apertura narium externa to the anterior margin of the orbit, as it does in other Bothremydini. The length of the suture, which reflects the width of the dorsal process, however, does vary among these. In the Bothremys species this process is wider than in any of the other Bothremydini. Chedighaii also has a wide process, wider than in other Bothremydini except for Bothremys.</p> <p>The maxilla forms the lateral margin of the apertura narium externa. In Bothremys the narium is relatively wide, as it is in most Bothremydini except Rosasia, Foxemys, and Polysternon. The extent of the maxilla from the orbit to the lower cheek margin is great in all species of Bothremys and in Chedighaii, more so than in other Bothremydini. The labial ridge in Bothremys maghrebiana is broadly curved as in B. cooki; both are very similar in shape laterally and ventrally.</p> <p>Contacts of horizontal plate: In Bothremys maghrebiana the maxilla contacts the premaxilla anteromedially, the vomer medially, the palatine posteromedially, and the jugal posteriorly. The vomer contact in B. maghrebiana is short in contrast to B. cooki, which has a long vomer-maxilla contact that is related to the longer anterior portion of the vomer and greater separation of the apertura narium interna from the front of the snout. The jugal contact in B. maghrebiana is also significantly different from that in B. cooki and is related to the way in which the triturating pits are formed (see below). In B. maghrebiana the jugal (see Jugal) is visible on the left side of AMNH 30041 and both sides of AMNH 30561. The jugal has an irregular, circular contact with the maxilla except for its posterior margin where it contacts the palatine. The maxilla also contacts the jugal dorsomedially in the posterior surface of the postorbital wall.</p> <p>Structures of horizontal plate: In Bothremys maghrebiana as in B. cooki and the other Bothremydini, except Araiochelys, the maxilla horizontal plate is very wide and triangular, forming most of the distinctive triturating surface.</p> <p>The triturating surface in Bothremys maghrebiana is most similar to that in B. cooki and B. kellyi among the Bothremydini, but there are important differences. The shape of the labial ridge is quite similar in B. cooki and B. maghrebiana, differing from Rosasia in being more acute and not as curved anteriorly. The ridge in Zolhafah is very blunt and much straighter than in any of the other Bothremydini. The labial ridge margin is missing in Chedighaii hutchisoni but it is acute in C. barberi. The medial and more horizontal surface of the triturating surface in B. maghrebiana is broadly curved, forming the outer parts of the surface leading into the pit, so that most of the pit is formed by the maxilla in B. maghrebiana. Only the tip is formed by the jugal. In the other species of Bothremys much more of the pit is formed by the jugal. However, the area of the triturating surface formed by the jugal in B. cooki is formed mostly by the palatine in B. maghrebiana, so the maxilla itself is similar in extent in these two species. The maxilla in both species reaches the edge of the temporal fossa to form part of the postorbital wall. This part of the triturating surface is also similar to that in Rosasia and Zolhafah; both of these have the jugal making up the tip of the pit, but the pit is shallower and lies closer to the temporal fossa edge, lacking the well-developed posterior wall seen in other Bothremys species. The maxilla in B. maghrebiana between the pit and the premaxilla is much less extensive than it is in B. cooki. Chedighaii lacks the triturating surface pits and lacks any exposure of the jugal on the triturating surface.</p> <p>Medially the maxilla in Bothremys maghrebiana forms part of the lingual ridge, much as in the other Bothremydini. The lingual ridge is not a ridge in the Bothremydini; rather, it forms a raised margin where the triturating surface is separated from the depressed area around the apertura narium externa. This area is very similar in the other Bothremys species.</p> <p>On the dorsal surface, the maxilla forms part of the floor of the fossa orbitalis and the orbital margin. The maxilla in B. maghrebiana forms the lateral edge of the foramen orbitonasale and the anterior part of the fossa orbitalis, as in B. cooki and the other Bothremydini. The maxilla in Bothremys maghrebiana forms a small part of the posterior surface of the postorbital wall. The maxilla forms part of the ventral pocket in the posterior part of the fossa orbitalis (fig. 144).</p> <p>VOMER (figs. 136, 137, 143)</p> <p>Preservation: In Bothremys maghrebiana the vomer is present in AMNH 30234, 30522, and 30561. It is well preserved with clear sutures in AMNH 30561 and 30522.</p> <p>Contacts: The contacts of the vomer in Bothremys maghrebiana are with the premaxillae anteriorly, the maxillae anterolaterally, and the palatines posteriorly, as in other Bothremydidae.</p> <p>Structures: The vomer in Bothremys maghrebiana is dumbbell-shaped, widened at each end with a narrow central bar. In B. cooki the anterior expansion is much more extensive and the maxillary contact is longer than in B. maghrebiana. Zolhafah also has a small or absent vomer-maxilla contact, but Rosasia has an anteriorly expanded vomer. Chedighaii has a vomer that lacks an anterior expansion of the sort seen in B. cooki, but the degree of maxilla contact is unclear.</p> <p>The vomer forms the medial margin of each apertura narium interna. In Bothremys maghrebiana the apertura is slightly larger than in B. cooki and is placed more anteriorly. The shape of the apertura is circular in B. cooki but oblong in B. maghrebiana. The foramen praepalatinum in B. maghrebiana is formed almost completely by the premaxilla.</p> <p>PALATINE (figs. 136, 137, 143)</p> <p>Preservation: Most of both palatines are missing in MHNL 20-268370, but the remaining four have the bone nearly complete on one or both sides. Sutures are clearest in AMNH 30561 and 30522.</p> <p>Contacts: The palatine in Bothremys maghrebiana contacts the maxilla in a long, roughly transverse suture trending anteromedially to posterolaterally with a short interruption in the middle for the jugal. This is in strong contrast to B. cooki, which has only the anteromedial part of the contact, as the larger jugal prevents more lateral contact with the maxilla. The anteromedial corner of the palatine has a short contact with the vomer. There is a long midline contact with the other palatine and a nearly transverse posterior contact with the pterygoid.</p> <p>On the dorsal surface of the palatine in B. maghrebiana there is the usual parasagittal contact with the processus inferior parietalis of the parietal. In the floor of the orbit the palatine contacts the maxilla anterolaterally, the jugal laterally, and the postorbital posterolaterally.</p> <p>Structures on dorsal surface of palatine: The orbital floor in Bothremys maghrebiana is exposed clearly in AMNH 30561 and 30041. The palatine exposure in B. maghrebiana is much as in B. cooki; there is not a great deal of variation within the Bothremydini in any case. The foramen orbitonasale is also similar in the other Bothremys species. There is no dorsal process of the palatine on either anterior or posterior postorbital wall surfaces.</p> <p>Structures on ventral surface of palatine: The palatine of Bothremys maghrebiana forms a significant part of the triturating surface, the posteromedial third, as in the other Bothremydini. This part of the palatine is broadly curved, forming the posteromedial part of the pit on the triturating surface. The triturating surface area of the palatine has the characteristic nutrient foramina up to the low lingual ridge that roughly trends anteromedially to posterolaterally, as in B. cooki.</p> <p>The palatine forms the dorsal and lateral walls of the apertura narium interna and the broadly curved choanal passage leading into it. This area is very similar in Bothremys maghrebiana and B. cooki.</p> <p>QUADRATE (figs. 136, 137, 139, 145, 286B)</p> <p>Preservation: The quadrate is present on both sides in AMNH 30234, AMNH 30561, and MHNL 20-268370, but it is missing on the right side of AMNH 30041 and is damaged on the right side of AMNH 30522. All five skulls show sutures.</p> <p>Contacts in lateral view: The quadrate in Bothremys maghrebiana contacts the maxilla anteriorly, the quadratojugal dorsally, and the squamosal posterodorsally.</p> <p>Structures in lateral view: The cheek in Bothremys maghrebiana is completely lacking any emargination and is very similar to Rosasia in this feature. Zolhafah and B. cooki do not have the cheek area preserved, and Chedighaii hutchisoni has a shallow emargination.</p> <p>The cavum tympani in Bothremys maghrebiana is similar to that in the other Bothremydini in which it is known (fig. 286B). Unfortunately, it is missing in the type specimen of B. cooki, although it is preserved in AMNH 29444, which is probably B. cooki. Rosasia and Zolhafah have only part of it preserved, so B. maghrebiana represents one of the best preserved ears in the Bothremydini ! Only Polysternon and Foxemys have good ear regions preserved and they differ significantly from B. maghrebiana and the other Bothremydini in having an open incisura columellae auris (fig. 281).</p> <p>The cavum tympani of Bothremys maghrebiana is a deep, hemispherical cone, as is typical of the infrafamily Bothremydodda, which have a nearly horizontal, shelflike platform forming its ventral edge. This area is not preserved in the type skull of B. cooki, but AMNH 29444 does have this shelf. The cavum tympani in B. maghrebiana has no fossa precolumellaris, a structure lacking in the other Bothremydidae except Kurmademys. As in all other Bothremydidae, B. maghrebiana has an extensive bony separation between the stapes and eustachian tube. There is a distinct groove and notch for the eustachian tube in B. maghrebiana, as in AMNH 29444 and both species of Chedighaii.</p> <p>The antrum postoticum in Bothremys maghrebiana shows some variation among the five skulls. In AMNH 30234, AMNH 30522, MHNL 20-268370, and AMNH 30561, the antrum is smaller than in AMNH 30041, the smallest skull. The smaller size of the antrum in the larger skulls suggests that it may be growth related, as in many living turtles. The antrum postoticum is often relatively larger in the juveniles of a species than in the adults, and the small condition in the larger skulls of B. maghrebiana may be the adult condition of this species. It is somewhat subjective to discriminate between ‘‘moderate’’ and ‘‘small’’ character states in the size of the antrum postoticum in bothremydids. However, the interpreted adult condition of B. maghrebiana is the same size as in the other Bothremys species and Chedighaii, but it is distinctly smaller than in Polysternon and Foxemys. The smallest B. maghrebiana skull, AMNH 30041, however, has an antrum postoticum about the same relative size as in these latter genera.</p> <p>Contacts in dorsal view: The quadrate in Bothremys maghrebiana has the usual contacts of most Bothremydini: prootic anteromedially, supraoccipital medially, opisthotic posteromedially, and squamosal posteriorly and posterolaterally.</p> <p>Structures in dorsal view: The only varying structure here is the position of the foramen stapedio-temporale. In Bothremys maghrebiana it is in the advanced bothremydid position on the anterior face of the otic chamber.</p> <p>Contacts in ventral view: The quadrate in turtles is a complex element that in bothremydids typically contacts nine bones (basisphenoid, basioccipital, pterygoid, opisthotic, prootic, supraoccipital, maxilla, quadratojugal, and squamosal; see fig. 136). These contacts are all present in Bothremys maghrebiana, and seven are visible in ventral view (all of the above except the supraoccipital and prootic). The medial process of the quadrate contacts the pterygoid anteromedially, the basisphenoid medially, and the basioccipital posterodorsally. These contacts are very similar in B. cooki (AMNH 29444) and Zolhafah. The basisphenoid suture is longer in Foxemys and Polysternon and much shorter in Chedighaii. Most of the basioccipital suture in Rosasia is eroded, but the basisphenoid suture seems similar in length to that in B. maghrebiana.</p> <p>Structures in ventral view: In ventral view the quadrate of Bothremys maghrebiana shows only the slightest imprint of the pterygoideus musculature, in strong contrast to the deep fossa pterygoidea seen in Foxemys and Polysternon. This concavity is also absent in Chedighaii, Zolhafah, and B. cooki (AMNH 29444), but a moderately developed one is present in Rosasia.</p> <p>The foramen posterius canalis carotici interni is formed between the quadrate and pterygoid in Bothremys maghrebiana (fig. 277B), as in B. cooki (AMNH 29444), Chedighaii, and B. arabicus, but in contrast to B. kellyi. The foramen is best preserved on the right side of AMNH 30041 and on the left side of AMNH 30234.</p> <p>The condylus mandibularis is at about the level of the basioccipital, just anterior to the condylus occipitalis, as in Foxemys, Chedighaii, Zolhafah, and B. cooki (AMNH 29444). It is distinct from the much more anterior placement seen in Polysternon.</p> <p>Contacts in posterior view: In Bothremys maghrebiana the quadrate contacts the squamosal dorsolaterally, the opisthotic dorsomedially, and the exoccipital medially. These are the usual contacts found in all the other Bothremydini.</p> <p>Structures in posterior view: The fenestra postotica of Bothremys maghrebiana is a single opening, partially divided by a shallow, dorsal ridge into a more medial and a more lateral portion (fig. 145). The dorsomedial part of the fenestra (fig. 145) is formed by the opisthotic, as in the other Bothremydini. In B. cooki (AMNH 29444, fig. 135), the fenestra is completely subdivided by bone into two openings, but its size is very similar to that in B. maghrebiana. The foramen chorda tympani inferius (fig. 145) is preserved on the posterior surface of the processus articularis of the quadrate in all B. maghrebiana specimens.</p> <p>PTERYGOID (figs. 136, 137, 139, 277B)</p> <p>Preservation: The pterygoid is present on both sides in all five skulls, with AMNH 30041, 30522, and 30561 showing clear sutures.</p> <p>Contacts on ventral surface: In Bothremys maghrebiana the pterygoid contacts the palatine anteriorly, the other pterygoid anteromedially, the basisphenoid posteromedially, and the quadrate posterolaterally. These contacts are as in the other Bothremydini, but the anteromedial pterygoid contact is very short in B. maghrebiana, shorter than in any other Bothremydini, but closest to B. cooki.</p> <p>Structures on ventral surface: The processus trochlearis pterygoidei is present on both sides in all five Bothremys maghrebiana skulls, and it appears to be nearly complete and undamaged in AMNH 30041. It is angled posterolaterally at about 45 °, more posterior than the process in Foxemys, Polysternon, and Chedighaii, but about the same as in B. cooki, Zolhafah, and Rosasia. Compared with Podocnemis, the processus in B. maghrebiana is relatively small, but compared with Pelusios and Pelomedusa it is about the same size. In comparison with the Pelomedusidae, however, the processus in those Bothremydini that have it well preserved show its position to be significantly closer to the otic chamber than in the Pelomedusidae. The web or flange of bone extending ventrally between the processus trochlearis pterygoidei and the quadrate ramus of the pterygoid is at least partially preserved in AMNH 30234, which shows it to be relatively extensive, as in the Pelomedusidae. The attachment margin of the pterygoideus muscle is marked in B. maghrebiana only by a low ridge or step extending transversely along the quadrate ramus of the pterygoid.</p> <p>The foramen posterius canalis carotici interni is formed anteriorly by the pterygoid (for description see Quadrate). The foramen palatinum posterius is in the suture between the pterygoid and palatine, which tends to be more transverse in Bothremys maghrebiana than in B. cooki and Foxemys. The foramen is slightly larger in B. maghrebiana than in B. cooki, which has a foramen smaller than other Bothremydini.</p> <p>Contacts on dorsal surface: The base of the processus trochlearis pterygoidei in Bothremys maghrebiana contacts the postorbital dorsolaterally, the parietal dorsally (see Parietal), and the palatine ventrolaterally (AMNH 30041). The crista pterygoidea, visible internally and externally in AMNH 30041, contacts the processus inferior parietalis dorsally, the prootic posterodorsally, and the quadrate posterolaterally.</p> <p>Structures on the dorsal surface: The sulcus palatinopterygoideus is formed between the processus trochlearis pterygoidei laterally and the processus inferior parietalis medially (fig. 144). In Bothremys maghrebiana this structure is completely enclosed by the pterygoid and parietal, but not the postorbital as in most other Bothremydini (fig. 278B). The sulcus enclosure is relatively short in B. maghrebiana as it is in B. cooki and the Chedighaii endocast (fig. 167), but in contrast to the Podocnemididae, which have a longer, more tunnel-like sulcus palatinopterygoideus. Although the sulcus in Bothremys is short, it is preceded anteriorly by an enlarged space in the posterior portion of the fossa orbitalis (see Postorbital). This space seems to be missing in the Chedighaii endocast, which shows a distinct ridge separating the nearly spherical fossa orbitalis from the sulcus palatinopterygoideus.</p> <p>The foramen palatinum posterius lies in the posterior floor of the sulcus palatinopterygoideus. It is slightly larger than in Bothremys cooki and much larger than the one in the Chedighaii endocast, AMNH 12951.</p> <p>The foramen nervi trigemini in Bothremys maghrebiana is formed by the pterygoid for its ventral length with the parietal entering it anterodorsally and the prootic posterodorsally. This is the same as in Bothremys cooki and Zolhafah. The pterygoid forms the floor of the sulcus/canalis cavernosus, which lies between the foramen nervi trigemini laterally and the processus clinoideus of the basisphenoid, with the foramen cavernosum just medial to the posterior margin of the foramen nervi trigemini. In B. maghrebiana the foramen stapedio-temporale is very close to the foramen nervi trigemini, as it is in most Bothremydini. The wall between the foramen stapedio-temporale and the foramen cavernosum is thinner in B. maghrebiana than it is in B. cooki (AMNH 29444). It is not preserved in the type skull of B. cooki. In Zolhafah it is completely eroded, exposing the canalis cavernosus as well as the canalis stapedio-temporalis.</p> <p>SUPRAOCCIPITAL (figs. 136, 139)</p> <p>Preservation: The occipital part of the supraoccipital is preserved in all five skulls, but the more posterior crista supraoccipitalis is complete in MHNL 20-268370 and AMNH 30041. AMNH 30561 is missing nearly all of the crista, and it is partially present in the others.</p> <p>Contacts: The supraoccipital contacts in Bothremys maghrebiana are with the parietals dorsally and anteriorly, the prootic anterolaterally, the quadrate laterally, the opisthotics posterolaterally, and the exoccipitals posteroventrally (seen best in AMNH 30561 and 30041). The quadrate-supraoccipital contact is found in all Bothremydini except Zolhafah and in all other Bothremydidae except the Taphrosphyini.</p> <p>Structures: The crista supraoccipitalis in Bothremys maghrebiana is relatively short, thickened along its ventral edge, and not projecting very far beyond the edge of the skull roof. The foramen magnum is formed by the supraoccipital dorsally, as in other pleurodires. The cavum labyrinthicum is not exposed in any of the B. maghrebiana skulls.</p> <p>EXOCCIPITAL (figs. 136, 145)</p> <p>Preservation: Both exoccipitals are present in all five Bothremys maghrebiana skulls; the best sutures are in AMNH 30561, although most sutures can be seen in all of them.</p> <p>Contacts: As in the other Bothremydini, the exoccipital of Bothremys maghrebiana contacts the supraoccipital dorsally, the opisthotic laterally, the quadrate ventrolaterally, and the basioccipital ventrally.</p> <p>Structures: The foramen magnum in Bothremys maghrebiana is formed laterally and ventrally by the exoccipital. The condylus occipitalis is formed entirely by the exoccipitals; the basioccipital does not extend posteriorly as in Cearachelys.</p> <p>There is only one foramen nervi hypoglossi in Bothremys maghrebiana, as in Polysternon and in contrast to Zolhafah, Chedighaii, Foxemys, and B. cooki (AMNH 29444), all of which have two. The single foramen of B. maghrebiana is placed close to the positions of the paired foramina in the other taxa, between the condylus occipitalis and the foramen jugulare posterius.</p> <p>The foramen jugulare posterius in Bothremys maghrebiana is fully enclosed. In AMNH 30561 it can be seen that the exoccipital forms the medial, dorsal, and ventral margins with the quadrate, with a very narrow edge of the opisthotic filling it in laterally. This is the same as in Zolhafah. In Chedighaii hutchisoni the opisthotic does not enter the foramen, but otherwise it is also the same. In B. cooki (AMNH 29444) the opisthotic does enter the foramen, but in NCSM 18650, a possible Chedighaii, it does not. The type skulls of B. cooki and C. barberi are indeterminate. In B. maghrebiana the foramen jugulare posterius has its lateral margin placed more anteriorly than the medial margin and it is overhung by the opisthotic. The size of the foramen jugulare posterius varies among the Bothremydini. In B. cooki (AMNH 29444) and NCSM 18650 it is much larger than in B. maghrebiana and the other Bothremydini. Among the B. maghrebiana specimens, the foramen jugulare posterius is smaller in AMNH 30234 than in the other skulls.</p> <p>BASIOCCIPITAL (figs. 136, 137, 277)</p> <p>Preservation: The basioccipital is present in all five skulls; sutures are best in AMNH 30561, 30522, and 30041.</p> <p>Contacts: The basioccipital in Bothremys maghrebiana agrees with those in other Bothremydini. It contacts the basisphenoid anteriorly, the quadrate laterally, and the exoccipitals dorsally.</p> <p>Structures: The basioccipital of Bothremys maghrebiana does not contribute to the condylus occipitalis or its neck. There is a paired tuberculum basioccipitale that is quite low, as in Zolhafah and Polysternon but in contrast to Foxemys and Chedighaii. The ventral surface of the basioccipital in B. maghrebiana has a shallow concavity similar to that seen in most other Bothremydini.</p> <p>PROOTIC (figs. 136, 143)</p> <p>Preservation: Both prootics are present in all five skulls, but the bone is best seen with clear sutures in AMNH 30561 and especially AMNH 30041, where preparation is most extensive.</p> <p>Contacts: The prootic of Bothremys maghrebiana has the usual Bothremydini contacts: the parietal medially, the quadrate laterally, the supraoccipital posterodorsally, and the pterygoid ventrally.</p> <p>Structures: The prootic of Bothremys maghrebiana contains the foramen stapedio-temporale, which is formed in the suture between the prootic and quadrate. The sutures around the foramen stapedio-temporale clearly show that, as in nearly all turtles, the quadrate and prootic make up the foramen. However, it is possible that a small part of the pterygoid enters it because the quadrate-pterygoid suture cannot be clearly seen in the region of the foramen stapedio-temporale. A groove connects the foramen stapedio-temporale medially with the lateral edge of the foramen nervi trigemini. The bar of bone between the two foramina seems to be the prootic, but this is also uncertain as the prootic-pterygoid suture is unclear and some of the bar could be pterygoid. The only other Bothremydini specimen that is well preserved in this area is B. cooki (AMNH 29444), and it shows the prootic nearly surrounding the foramen stapedio-temporale with only a small area of quadrate at its ventrolateral border (fig. 132). The bar of bone separating the two foramina in this specimen is entirely prootic.</p> <p>On the left side of AMNH 30041 the quadrate is missing along the prootic suture. This shows the path of the canalis stapedio-temporalis, the canalis cavernosus, and the cavum labyrinthicum.</p> <p>OPISTHOTIC (figs. 136, 143, 145)</p> <p>Preservation: The opisthotic is present on both sides of all five skulls. Sutures are clearest in AMNH 30561, but the absence of the quadrate in AMNH 30041 makes the internal area of the opisthotic visible.</p> <p>Contacts: The opisthotic contacts in Bothremys maghrebiana are as in other</p> <p>Bothremydini: supraoccipital anteromedially, squamosal posterolaterally, quadrate anterolaterally, and exoccipital posteromedially. In the cavum cranii, the opisthotic is visible in AMNH 30041, and the opisthotic does not seem to contact the basioccipital or basisphenoid, but this is not certain.</p> <p>Structures: In posterior view the opisthotic forms a horizontal ridge from the exoccipital to the squamosal in Bothremys maghrebiana and most Bothremydini. Ventral to the ridge at the lateral edge of the opisthotic, this bone forms the dorsomedial margin of the fenestra postotica, most of which is formed by the quadrate (see Quadrate).</p> <p>In AMNH 30041 the roof of the cavum acustico-jugulare can be seen, largely made of opisthotic. The fenestra ovalis is visible medially, formed posteriorly by the (mostly missing) opisthotic and anteriorly by the prootic, as in all turtles. Much of the cavum labyrinthicum is also visible, also agreeing with other turtles.</p> <p>BASISPHENOID (figs. 136, 137, 139, 277B)</p> <p>Preservation: The basisphenoid is present in all five skulls. Sutures are best seen in AMNH 30561, 30522, and 30041. The dorsal surface is visible in AMNH 30041.</p> <p>Contacts in ventral view: The basisphenoid of Bothremys maghrebiana has the usual contacts of the Bothremydini: pterygoid anterolaterally, basioccipital posteriorly, and quadrate posterolaterally.</p> <p>Structures in ventral view: The basisphenoid of Bothremys maghrebiana is nearly triangular with a sharp apex that almost completely separates the pterygoids and nearly reaches the palatines. B. cooki is similar but not as extreme, while the other Bothremydini have longer midline pterygoid contacts.</p> <p>Contacts in dorsal view: The basisphenoid of Bothremys maghrebiana completely separates the pterygoid and reaches the palatines on the dorsal surface, in the floor of the cavum. The other contacts are as in turtles generally: prootic laterally and basioccipital posteriorly.</p> <p>Structures in dorsal view: The rostrum basisphenoidale in Bothremys maghrebiana and the other Bothremydini is fused into a midline process similar to that seen in Pelusios (fig. 23). The rostrum of B. cooki, Chedighaii barberi, and the Chedighaii endocast, YPM PU 12951 (fig. 167), are longer and narrower, as in Podocnemis (Gaffney, 1979a: fig. 54). The sella turcica in B. maghrebiana is slightly wider than in B. cooki so that the paired foramen anterius canalis carotici interni are visible in dorsal view. The dorsum sellae does not overhang the sella turcica in B. maghrebiana to the extent it does in B. cooki or YPM PU 12951. The basisphenoid in Zolhafah is not well preserved or completely prepared, but the rostrum is short, as in B. maghrebiana.</p> <p>The processus clinoideus in nearly all turtles is penetrated at or near its base by the canal for the abducens nerve (Gaffney, 1979a). In Bothremys maghrebiana, B. cooki, Chedighaii endocast, YPM PU 12951, and probably Chedighaii barberi, the processus clinoideus is absent and the canalis nervi abducentis is a groove (Gaffney, 1977a: fig. 3). The distribution of this character is hard to determine, but it may be unique to Bothremys + Chedighaii.</p> <p>Bothremys kellyi</p> <p>Known from one relatively well-preserved skull, this taxon is allied (although weakly, see fig. 288) with the other large Bothremydini, Bothremys arabicus, from the Late Cretaceous of Jordan. The basicranium is damaged but the remaining parts of the skull are intact and the sutures are clear.</p> <p>PREFRONTAL (figs. 146, 149)</p> <p>Preservation: Both prefrontals are nearly complete.</p> <p>Contacts: The prefrontal in Bothremys kellyi has the usual Bothremydini contacts: the maxilla anteroventrolaterally, the other prefrontal medially, and the frontal posteriorly. There is also an anteroventral contact on the midline with a dorsal process of the premaxilla, as in Araiochelys but in contrast to all other Bothremydini.</p> <p>Structures: The dorsal margin of the apertura narium externa has a midline protrusion formed by the prefrontal in B. kellyi, other Bothremys, and most Bothremydini. The dorsal margin of the orbit is widely separated from the midline in B. kellyi, slightly more than in other Bothremys species. The sulcus olfactorius is slightly wider in B. kellyi than in other Bothremys species. Although the area is damaged on both sides, it is highly likely that there is a wide prefrontal-palatine contact in the anterior part of the fossa orbitalis, as in B. maghrebiana.</p> <p>FRONTAL (figs. 146, 149)</p> <p>Preservation: Both frontals are present and complete.</p> <p>Contacts: As in Bothremys cooki. The frontal of B. kellyi is slightly wider than in B.</p></div> 	https://treatment.plazi.org/id/4E7B8791CE43FEECFD7FFF4717E18ECA	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	GAFFNEY, EUGENE S;TONG, HAIYAN;MEYLAN, PETER A	GAFFNEY, EUGENE S, TONG, HAIYAN, MEYLAN, PETER A (2006): EVOLUTION OF THE SIDE-NECKED TURTLES: THE FAMILIES BOTHREMYDIDAE, EURAXEMYDIDAE, AND ARARIPEMYDIDAE. Bulletin of the American Museum of Natural History 300 (300): 1-698, DOI: 10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2, URL: http://dx.doi.org/10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2
4E7B8791CE1BFE72FC99FA5314968C84.text	4E7B8791CE1BFE72FC99FA5314968C84.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Chedighaii barberi Gaffney & Tong & Meylan 2006	<div><p>Chedighaii barberi</p> <p>Two partial skulls and a skull endocast are the basis for the skull descriptions for this taxon. The species type specimen is a shell (Schmidt, 1940). The two skulls have shell material associated with them that is the basis for the identification. However, considering the conservative nature of other bothremydid shells, it is possible that more than one species have similar shells and that the cranial material here identified as C. barberi represents more than one species. Furthermore, the skulls are not complete enough to be sure that there are not some differences that have been missed due to nonpreservation. Nonetheless, the two skulls agree in all the preserved areas. Another consideration is the wide geographic spread (fig. 18) of shells attributable to Chedighaii, consistent with more than one species. See Note Added in Proof.</p> <p>The endocast (figs. 166, 167) is identified as C. barberi because it agrees closely with the two partial skulls. The endocast is not just the cavum cranii but almost the entire (negative) skull, including the fossa orbitalis and fossa nasalis. The fact that it lacks pits (although subtle) was missed by the original describer (Gaffney, 1977a; hey, it was a long time ago). The endocast shows some interesting information about the skull (see below), and a mold of the endocast allows direct comparisons to be made with the other skull specimens.</p> <p>In the collections of the North Carolina State Museum is a series of otic chambers from the Campanian Tar Heel Formation of North Carolina (Gaffney and Schneider, ms.). These chambers are indistinguishable from the Chedighaii barberi ear regions available from the Selma Formation skulls but are too incomplete to be identified with certainty as C. barberi. The quadrate of one of these is figured here (fig. 286D).</p> <p>One of the partial skulls, FMNH PR 247, was described by Gaffney and Zangerl (1968), and the endocast, YPM PU 12951, was described by Gaffney (1977a).</p> <p>PREFRONTAL (figs. 160, 165)</p> <p>Preservation: Portions of both prefrontals are present in ALAB PV 2001.2, with the left prefrontal being the most complete among the three specimens. This bone has the prefrontal descending process, the anterior margin, and part of the orbital rim preserved. The right prefrontal has only the horizontal area next to the midline. Both prefrontals preserve the ventral surface. In FMNH PR 247 portions of the horizontal plates of both prefrontals are present, but the margins are eroded. In the endocast, there are small fragments of both prefrontals anteriorly, and part of the ventral surface is on the endocast.</p> <p>Contacts: The visible contacts in all three Chedighaii barberi specimens show the prefrontal meeting the other prefrontal medially, the maxilla anteroventrolaterally, and the frontal posteriorly. The maxillary contact does not form a dorsal extension as in Bothremys cooki and B. maghrebiana. The palatine is not well preserved, so possible contacts or a close approximation of palatine and prefrontal as in C. hutchisoni is not determinable.</p> <p>Stuctures: The dorsal plate of the prefrontal in Chedighaii barberi is very similar to that in C. hutchisoni. There is a midline projection that is nearly identical in extent and shape, and the shape of the apertura narium externa margin is the same. The dorsal margin of the orbital rim is not preserved in any specimen except the endocast, and this shows that the interorbital distance in C. barberi is relatively narrow, as in C. hutchisoni but in contrast to the wider distance in Bothremys.</p> <p>FRONTAL (figs. 160, 165)</p> <p>Preservation: Parts of both frontals are preserved in FMNH PR 247 and ALAB PV 2001.2, but neither has the lateral, orbital margin region preserved. The endocast has the ventral surface of both frontals visible.</p> <p>Contacts: The frontal in Chedighaii barberi contacts the other frontal medially, the prefrontal anteriorly, the parietal posteriorly, and the postorbital (visible only in the endocast) posterolaterally, all as in other Bothremydini.</p> <p>Structures: The orbital margin is seen only in the endocast, which shows that Chedighaii barberi has the orbits facing dorsally, as in Bothremys and C. hutchisoni, as well as relatively small orbital openings, also in these taxa. The sulcus olfactorius is relatively narrow, as in C. hutchisoni and Bothremys.</p> <p>PARIETAL (figs. 160, 165)</p> <p>Preservation: The medial parts of both parietals are present in ALAB PV 2001.2 and FMNH PR 247; part of the ventral surface is in YPM PU 12951.</p> <p>Contacts of dorsal plate: The parietal in Chedighaii barberi contacts the frontal anteriorly, the other parietal medially, and the supraoccipital posteroventrally. The lateral contact with the postorbital is visible in the endocast.</p> <p>Structures of dorsal plate: The limits of the temporal roof are not preserved in any of the Chedighaii barberi specimens. In the endocast, the parietal has a ventral process forming part of the posterior wall of the fossa orbitalis, lateral to the sulcus palatinopterygoideus, as in other Bothremydini.</p> <p>Contacts of processus inferior parietalis: Only the dorsal part of the processus is preserved in FMNH PR 247 and ALAB PV 2001.2; no ventral contacts are preserved. In YPM PU 12951 most of the processus is preserved on both sides, but the ventral contacts are missing.</p> <p>Structures of processus inferior parietalis: The foramen interorbitale of Chedighaii barberi is preserved only in the endocast, and it is very similar to that in C. hutchisoni. The foramen nervi trigemini is not preserved.</p> <p>JUGAL (figs. 160, 165, 167)</p> <p>Preservation: The jugal is preserved only on the right side of ALAB PV 2001.2 and in the endocast as an imprint. The portion preserved in ALAB PV 2001.2 is a thin layer of the medial process that lies posterior to the maxilla and forms the anterior wall of the temporal chamber. The endocast portion is the region of the jugal forming part of the fossa orbitalis.</p> <p>Contacts of lateral plate: Not preserved.</p> <p>Structures of lateral plate: Not preserved.</p> <p>Contacts of medial process: In the floor of the fossa orbitalis, the jugal contacts the maxilla anteromedially and the palatine medially. In the septum orbitotemporale, the jugal contacts the postorbital dorsomedially. The portion of the medial process preserved in ALAB PV 2001.2 contacts the maxilla only.</p> <p>Structures of medial process: The endocast and the partial skull, ALAB PV 2001.2, show that Chedighaii barberi did not have the jugal forming part of a pit on the triturating surfaces as in Bothremys. This is clear from ALAB PV 2001.2 alone, because it is the posterior part of the triturating surface on the maxilla that is actually preserved (figs. 164, 165). In YPM PU 12951 (figs. 166, 167) it is less obvious, but the jugal and maxilla form a deep rim below the orbital margin, as in C. hutchisoni, which is very different from the absent rim of Bothremys cooki. The pit itself would not be seen in the endocast, but the floor of the fossa orbitalis is clearly very similar in C. hutchisoni and C. barberi and distinct from the floor in Bothremys.</p> <p>The pitted bothremydids all have at least some of the jugal significantly altered from the primitive condition to form part of the pit. Enough of the jugal (and maxilla) is preserved in C. barberi to show that a pit was absent and that the jugal has no exposure on the triturating surface. The jugal in C. barberi is exposed in the anterior wall of the fossa temporalis, as in C. hutchisoni.</p> <p>QUADRATOJUGAL</p> <p>Preservation: No fragment remains of the poor quadratojugal in any of the three Chedighaii barberi specimens.</p> <p>SQUAMOSAL (figs. 160, 165)</p> <p>Preservation: Most of both squamosals are present in ALAB PV 2001.2, but only a fragment remains in FMNH PR 247. The anterodorsal margin is missing on both sides of ALAB PV 2001.2. The endocast has nothing of this bone.</p> <p>Contacts: The squamosal in Chedighaii barberi contacts the quadrate anteriorly and anteromedially and the opisthotic medially. The anterodorsal margin is missing; a quadratojugal contact cannot be determined.</p> <p>Structures: The squamosal in Chedighaii barberi has the posterior triangular projection typical of the Bothremydini, with a ventral ridge and thin, dorsolateral shelf continuing the line of the temporal emargination. The antrum postoticum is a narrow canal, as in Bothremys and C. hutchisoni.</p> <p>POSTORBITAL (fig. 167)</p> <p>Preservation: The only postorbital information for Chedighaii barberi is on the endocast which shows the exposure of the bone in the posterior wall of the fossa orbitalis.</p> <p>Contacts and structures of lateral plate: Not preserved.</p> <p>Contacts of medial process: In the endocast the fossa orbitalis shows the postorbital contacting the frontal anteromedially, the parietal posteromedially, the jugal ventrolaterally, and the palatine ventrally.</p> <p>Structures of medial process: Only the endocast provides information on this area,</p> <p>and it shows the fossa orbitalis, that is, the anterior wall of the septum orbitotemporale. The fossa orbitalis of Chedighaii barberi has a large posterior/posteroventral chamber formed primarily by the postorbital, jugal, parietal, and palatine. This chamber is particularly apparent in the endocast when the anterior position of the orbital margin is compared with the rest of the fossa. This posteroventral chamber in C. barberi is very similar to the one in C. hutchisoni, but the chamber is present in nearly all bothremydids.</p> <p>PREMAXILLA (figs. 160, 161, 165, 167)</p> <p>Preservation: The left premaxilla, lacking its more medial portion, and a small part of the right oneare preserved in ALAB PV 2001.2. The endocast shows the dorsal surface of the premaxilla.</p> <p>Contacts: The premaxilla contacts the maxilla posteriorly and the other premaxilla medially. A possible vomer contact is not preserved.</p> <p>Structures on dorsal surface: The endocast shows a relatively large premaxilla forming the floor of a wide fossa nasalis. The fossa is also wide in Chedighaii hutchisoni, although its floor and the premaxillae are missing. The fossa in Bothremys seems to be relatively narrower. The foramen praepalatinum lies within the premaxilla. It seems unlikely that a dorsal process, as in Araiochelys and Bothremys, was present in C. barberi. The endocast shows a relatively flat floor anteriorly, although the actual margin of the apertura narium externa is not present.</p> <p>The ventral margin of the apertura narium externa is preserved laterally in ALAB PV 2001.2, and it shows a protuberant premaxilla, distinct from Bothremys and other Bothremydini. The midline portion is missing, so its complete outline is unknown, but it clearly had an apertura that faced more dorsally than in the other Bothremydini. Unfortunately, the ventral part of the apertura is missing in Chedighaii hutchisoni.</p> <p>Structures on ventral surface: The labial ridge in Chedighaii barberi is straight, in contrast to the pinched or curved one in other Bothremydini. The premaxilla edge continues the shape and line of the maxilla edge. The ridge is acute along the margin; its surface is curved convex laterally and flat medially. None of the medial plate is preserved.</p> <p>MAXILLA (figs. 160, 161, 165, 167)</p> <p>Preservation: Nearly all of the vertical plate is preserved on the left side of ALAB PV 2001.2 and much of it on the right. The endocast preserves the maxillary surface inside the fossa nasalis and fossa orbitalis.</p> <p>Contacts of vertical plate: The right and left maxillae of ALAB PV 2001.2 show the anterior contact with the premaxilla. The left maxilla has the anterodorsal contact with the prefrontal. The prefrontal extends ventrally along the dorsal process of the maxilla, as in Chedighaii hutchisoni, and probably comes close to a palatine contact. The palatine is present on the left side of ALAB PV 2001.2, but it is broken in the area of possible prefrontal contact. The position of the jugal contact on the lateral surface of the maxilla is indeterminate. The possible contact of the maxilla with the quadrate and quadratojugal is also indeterminate.</p> <p>Structures of vertical plate: The orbital margin is not preserved in ALAB PV 2001.2 or FMNH PR 247, but in ALAB PV 2001.2 much of the rim is present. This agrees with the endocast in showing that there was a high rim above the floor of the fossa orbitalis. The deep maxilla seen in Chedighaii barberi also occurs in C. hutchisoni and Bothremys. The maxilla forms the dorsolateral edge of the apertura narium externa (see also Premaxilla, Prefrontal). In C. barberi the apertura is strongly inclined so that it faces anterodorsally, probably as in C. hutchisoni but in contrast to other Bothremydini, which are not as strongly inclined. The fossa nasalis in C. barberi is relatively wide, as in C. hutchisoni and Bothremys. It leads into the choanal passages, seen in the endocast and in fragments in ALAB PV 2001.2.</p> <p>Contacts of horizontal plate: The maxilla contacts the premaxilla anteriorly, but the medial plate here is missing. The posteromedial maxilla-palatine contact is preserved in part on the left side of ALAB PV 2001.2, as is the jugal contact posterolaterally (see Jugal). In the endocast, the floor of the fossa orbitalis shows the dorsal surface contacts: palatine posteromedially and the jugal posterolaterally.</p> <p>Structures of horizontal plate: The triturating surface in Chedighaii barberi is preserved only to a limited extent. Anteriorly it is missing, but the posterior part can be determined accurately using the two maxillae preserved in ALAB PV 2001.2. The labial ridge on the maxilla is as described for the premaxilla: relatively thin, acute margin, outer surface convex laterally, inner surface flat. The labial ridge in ventral view is straight, in contrast to Bothremys and other Bothremydini. Although curved, only Araiochelys, in addition to C. barberi, has a fairly thin labial ridge. It is possible, of course, that C. hutchisoni also has a narrow labial ridge, but this area is not known in that species. In lateral view, the labial ridge of C. barberi is slightly curved, concave ventrally. This is also unique among Bothremydini.</p> <p>The triturating surface of Chedighaii barberi is only preserved in a short section on the left side of ALAB PV 2001.2. Nonetheless, there is enough preserved to determine that pits are absent and that it is much narrower than in C. hutchisoni. The part of maxilla preserved in ALAB PV 2001.2 shows a broad curve from the sloped internal surface of the labial ridge to the horizontal medial plate of the maxilla. In the pitted bothremydids this area is clearly marked by the concavity for the pit. The jugal in ALAB PV 2001.2 is not exposed in the triturating surface, and less of the palatine is exposed. The broad curved surface of the triturating surface in ALAB PV 2001.2 is narrower than in C. hutchisoni, and the angle of inclination of the labial ridge is somewhat more acute in C. barberi, presumably correlated with the narrower surface. The anterior median concavity is not preserved in C. barberi, but the medial edge of the triturating surface allows a certain amount of restoration to be controlled. It seems unlikely that in C. barberi there would be room for a wide anterior median concavity as seen in C. hutchisoni. A more likely size would be that seen in Bothremys cooki and Araiochelys.</p> <p>VOMER Preservation: Not preserved.</p> <p>PALATINE (figs. 160, 161, 165, 167)</p> <p>Preservation: Part of the palatine just medial to the maxilla is present on the left side of ALAB PV 2001.2. The right maxilla in ALAB PV 2001.2 also has a small piece of palatine in this area. The endocast shows most of the dorsal surface of the palatine, but its anteromedial part is missing. Part of both palatines remains just anterior to the pterygoid in FMNH PR 247.</p> <p>Contacts: The palatine contacts the maxilla anterolaterally, the other palatine medially, the pterygoid posteriorly, and the parietal dorsally in the anterior surface of the septum orbitotemporale. A possible vomer contact is indeterminate. The floor of the fossa orbitalis shows the palatine contacting the jugal anterolaterally, the maxilla anteriorly, and the postorbital dorsally.</p> <p>Structures on dorsal surface: The palatine forms the posterior floor and much of the posterior wall of the fossa orbitalis, as in Chedighaii hutchisoni. The fossa orbitalis in C. barberi has the posteroventral enlargement seen in C. hutchisoni, Bothremys, Araiochelys, and Rosasia. The endocast shows this structure particularly well.</p> <p>Structures on ventral surface: The palatine section preserved in ALAB PV 2001.2 lies just medial to the maxilla and forms the medial edge of the triturating surface. There is a narrow ledge above the triturating surface that curves medially to form the choanal wall. There is no real lingual ridge in either Chedighaii species; the edge just turns dorsally at its margin. The angle of the medial edge of the triturating surface seems to preclude a wide anterior median concavity (see Maxilla) in C. barberi; instead, a narrow one, as in Araiochelys and Bothremys cooki, seems more likely. The apertura narium interna is also probably much narrower in C. barberi than in C. hutchisoni, but the posterior entry of the choanal passage seems about the same width.</p> <p>QUADRATE (figs. 160, 163, 165, 286D)</p> <p>Preservation: Most of both quadrates are present in ALAB PV 2001.2, but they lack the contacts with cheek elements and are broken around the anterior margin of the cavum tympani. In FMNH PR 247 most of the right quadrate is present, but it also lacks sutural contacts around the cavum tympani margins. The endocast has no quadrate information. A number of otic chambers probably belonging to Chedighaii barberi are in the North Carolina State Museum and are being described by Gaffney and Schneider (ms). One of these chambers, NCSM 12766, is figured here (fig. 286D).</p> <p>Contacts on lateral surface: The only lateral contacts preserved are with the squamosal, which the quadrate contacts posterodorsally.</p> <p>Structures on lateral surface: The cavum tympani can be determined using both ALAB PV 2001.2 and FMNH PR 247, although FMNH PR 247 is the most complete. The cavum in Chedighaii barberi is similar to that in C. hutchisoni: fossa precolumellaris absent, incisura columellae auris fully enclosed by bone and widely separated from the sulcus eustachii, antrum postoticum relatively small and tubelike, and shelf below cavum tympani present. The antrum in C. barberi,</p> <p>however, is smaller than that in C. hutchisoni.</p> <p>Contacts on dorsal and anterior surfaces: As in Chedighaii hutchisoni and other Bothremydini, the quadrate in C. barberi contacts the prootic anteromedially, the opisthotic posteromedially, the supraoccipital medially, and the squamosal posterolaterally.</p> <p>Structures on dorsal and anterior surfaces: The foramen stapedio-temporale in C. barberi is best seen in FMNH PR 247 and is well anterior on the otic chamber, near the foramen nervi trigemini.</p> <p>Contacts on ventral surface: The quadrate contacts the pterygoid anteromedially, the basisphenoid medially, and the basioccipital posteromedially.</p> <p>Structures on ventral surface: There is no fossa pterygoidea in Chedighaii barberi or C. hutchisoni, however, the bone surface is slightly depressed (so am I) around the foramen posterius canalis carotici interni in both species. The foramen posterius canalis carotici interni is formed by the pterygoid anteriorly and the quadrate posteriorly, as in C. hutchisoni, B. cooki, B. maghrebiana, Araiochelys, and B. arabicus. The condylus mandibularis in C. barberi is slightly anterior to the condylus occipitalis, whereas in C. hutchisoni it is even with the condylus occipitalis.</p> <p>Contacts on posterior surface: The quadrate contacts the squamosal dorsolaterally, the opisthotic dorsomedially, the exoccipital medially, and the basioccipital ventromedially.</p> <p>Structures on the posterior surface: The occipital surface of the skull in ALAB PV 2001.2 and FMNH PR 247 is not well preserved, so all the features cannot be seen clearly. The fenestra postotica is completely separated into two foramina (right side of ALAB PV 2001.2): a smaller, dorsomedial one for the stapedial artery, and a larger, ventrolateral one for the infamous lateral head vein. These divisions are only low ridges in Chedighaii hutchisoni.</p> <p>PTERYGOID (figs. 160, 161, 163, 165, 167)</p> <p>Preservation: All three specimens of Chedighaii barberi have some part of the pterygoid preserved, but none is even partially complete. The two sides of ALAB PV 2001.2 have the best pterygoids, with both lacking the processus trochlearis pterygoidei, the lateral margins, and the thin bone near the foramen nervi trigemini. The posterior and medial part of the right pterygoid remains in FMNH PR 247, but the bone surface is eroded. The endocast shows the medial dorsal surface of the pterygoid and some of the sulcus palatinopterygoideus floor.</p> <p>Contacts on ventral surface: The pterygoid contacts the palatine anteriorly (only a few fragments of bone in ALAB PV 2001.2 and a small part of the palatine in FMNH PR 247), the quadrate posterolaterally, the other pterygoid medially, and the basisphenoid posteromedially. The basisphenoid contact is straight in Chedighaii barberi and curved in C. hutchisoni.</p> <p>Structures on ventral surface: The processus trochlearis pterygoidei and associated flange are missing. The fossa pterygoidea is absent, but there is a shallow depression around the foramen posterius canalis carotici interni, which is formed between the pterygoid and quadrate. The foramen palatinum posterius medial margin that is formed by the pterygoid is present on both sides of ALAB PV 2001.2. It is in about the same position as in Chedighaii hutchisoni.</p> <p>Contacts on dorsal surface: Although much of the dorsal surface of the pterygoid is visible, the crista pterygoidea is broken off close to its base in both ALAB PV 2001.2 and FMNH PR 247 and it is obscured by matrix in YPM PU 12951.</p> <p>Structures on dorsal surface: A portion of the damaged foramen nervi trigemini is preserved on the left side of ALAB PV 2001.2 and shows that the pterygoid entered the foramen. Part of the sulcus and canalis cavernosus is adjacent.</p> <p>SUPRAOCCIPITAL (figs. 160, 163, 167)</p> <p>Preservation: The anterior part of the supraoccipital, lacking all but the base of the crista supraoccipitalis, is present in FMNH PR 247. A small section of the cavum cranii in YPM PU 12951 shows a supraoccipital imprint. A small part of the anteroventral edge and the lateral processes are preserved in ALAB PV 2001.2.</p> <p>Contacts: The supraoccipital contacts the parietals anterodorsally, the prootic anterolaterally, the quadrate laterally (this is incorrectly identified as opisthotic in Gaffney and Zangerl, 1968: fig. 18), and the exoccipitals posteroventrally.</p> <p>Structures: The base of the crista supraoccipitalis is preserved and it agrees with that in Chedighaii hutchisoni.</p> <p>EXOCCIPITAL (figs. 160, 163, 165)</p> <p>Preservation: Most of the right exoccipital is present in FMNH PR 247, but it is eroded and not well preserved so that sutures and foramina are unclear. The better preserved ALAB PV 2001.2 has some of both exoccipitals present, but the condylus occipitalis and most of the dorsal portions are broken away.</p> <p>Contacts: The exoccipital in Chedighaii barberi contacts the supraoccipital dorsally, the opisthotic laterally, the quadrate ventrolaterally, and the basioccipital ventrally.</p> <p>Structures: The shape of the foramen magnum in Chedighaii barberi cannot be determined, although one was almost certainly present. The only part of the condylus occipitalis preserved is in FMNH PR 247, and it does not show sutures; most of the bone surface is eroded away. The foramen nervi hypoglossi are present, but their position relative to sutures is unclear. The foramen jugulare posterius is also not well preserved. The fenestra postotica is widely separated by bone from the foramen jugulare posterius, and the lateral margin of the foramen jugulare posterius is largely present, showing that it was closed.</p> <p>BASIOCCIPITAL (figs. 160, 163, 165)</p> <p>Preservation: Most of the basioccipital is present in ALAB PV 2001.2 and FMNH PR 247, but it is damaged and the condylus occipitalis is missing or badly preserved.</p> <p>Contacts: The basioccipital in Chedighaii barberi contacts the basisphenoid anteriorly, the quadrate laterally, and the exoccipital posterodorsally, as in the other Bothremydini.</p> <p>Structures: Whether the basioccipital in Chedighaii barberi contributes to the condylus occipitalis cannot be determined. Distinct but shallow tubercula basioccipitale are present in C. barberi, and they are very similar in shape and position to those in C. hutchisoni. There is a shallow median concavity in C. barberi that is also the same as in C. hutchisoni.</p> <p>PROOTIC (figs. 160, 163)</p> <p>Preservation: The best prootic is on the right side of FMNH PR 247, with only small portions of the prootic remaining in ALAB PV 2001.2.</p> <p>Contacts: The prootic in Chedighaii barberi contacts the parietal dorsomedially, the quadrate laterally, and the supraoccipital posterodorsally. The dorsal opisthotic contact is prevented by the broad quadrate-supraoccipital contact, as in most Bothremydini. The ventral pterygoid contact is likely but not preserved.</p> <p>Structures: Very little of the internal features of the prootic are visible, although the path of the foramen nervi facialis can be seen on the left side of ALAB PV 2001.2. The position of the foramen nervi trigemini can be made out in both ALAB PV 2001.2 and FMNH PR 247, but its margins are gone.</p> <p>OPISTHOTIC (figs. 160, 163, 165)</p> <p>Preservation: Both opisthotics are present in ALAB PV 2001.2, missing their posterior edges and thinner occipital processes. The same is true of FMNH PR 247, but it also suffers from erosion disease.</p> <p>Contacts: The opisthotic in Chedighaii barberi contacts the supraoccipital anteromedially, the quadrate anterolaterally, the squamosal posterolaterally, and the exoccipital posteromedially.</p> <p>Structures: The fenestra postotica in Chedighaii barberi (see Quadrate) is subdivided into two foramina; its medial limits are formed by the opisthotic. The foramen jugulare posterius (see Exoccipital) is enclosed by bone and widely separated from the fenestra postotica.</p> <p>BASISPHENOID (figs. 160, 163, 165, 167)</p> <p>Preservation: All three skulls of Chedighaii barberi preserve the basisphenoid. Dorsal and ventral surfaces are in ALAB PV 2001.2, but it is missing its posterodorsal part and has breakage dorsally. All of the bone is present in FMNH PR 247, but the bone surface is eroded. The endocast shows nearly all of the dorsal surface in high fidelity (see also Gaffney, 1977a: fig. 3).</p> <p>Contacts on ventral surface: The basisphenoid in Chedighaii barberi contacts the pterygoid anterolaterally, the basioccipital in a straight suture posteriorly, and the quadrate in a very narrow suture posterolaterally.</p> <p>Structures on ventral surface: The ventral surface in Chedighaii barberi is flat, as in C. hutchisoni.</p> <p>Contacts on dorsal surface: The basisphenoid in Chedighaii barberi contacts the pterygoid anterolaterally, the prootic laterally (seen in endocast), and the basioccipital posteriorly.</p> <p>Structures on dorsal surface: The rostrum basisphenoidale in Chedighaii barberi (Gaffney, 1977a: fig. 3) is an elongate rod, seen in all three specimens, that is similar in length and width to that in Podocnemis (Gaffney, 1979a: fig. 54) rather than to the rostrum in Pelusios (fig. 24), which is wider and shorter. The sella turcica is elongate and deep, also as in Podocnemis and in contrast to Pelusios. The dorsum sellae in C. barberi overhangs the sella turcica to a greater extent than usually seen in Pelusios or Podocnemis. The foramen anterius canalis carotici interni lie at the corners of the sella turcica as usual. The processus clinoideus is absent; the canalis nervi abducentis is a shallow groove. This condition also occurs in Bothremys cooki and B. maghrebiana.</p> <p>TRIBE TAPHROSPHYINI SUBTRIBE TAPHROSPHYINA Taphrosphys sulcatus</p> <p>This, the first described bothremydid (Leidy, 1856, as Platemys sulcatus), is still known only from three incomplete skulls, as well as from a great deal of partial shell material. One of three species making up the genus, Taphrosphys sulcatus, is weakly supported as the sister taxon to T. ippolitoi. Taphrosphys itself is the sister group to Rhothonemys, Phosphatochelys, and Ummulisani.</p> <p>Taphrosphys ippolitoi has the most complete cranial material of the three species. The three species of Taphrosphys are described in three separate sections, but only one species has the primary description and comparisons, depending on which species has the best preserved bone being described. The reader will therefore need to look at all three sections even if only one species is of interest. The particular species that has the best bone description for that particular element is always indicated in all three species descriptions.</p> <p>PREFRONTAL (figs. 168, 170)</p> <p>Preservation: Both prefrontals are present in ANSP 15544 and are undistorted.</p> <p>However, the ventral process on both sides is broken off.</p> <p>Contacts: In ANSP 15544 the prefrontal only contacts the parietal posteriorly and the other prefrontal medially, as the maxilla is missing. As in the other two Taphrosphys species, the frontal underlies the prefrontal ventrally, forming a V-shaped suture with the apex on the median suture line.</p> <p>Structures: The prefrontal dorsal plate in Taphrosphys sulcatus is very similar to that in T. congolensis and Azabbaremys. It is smooth and lacks the swelling seen in T. ippolitoi. As in T. ippolitoi and T. congolensis the prefrontal in T. sulcatus is relatively thick, particularly along the midline, in contrast to most other bothremydids (e.g., Galianemys).</p> <p>The ventral surface of the prefrontal is visible in Taphrosphys sulcatus. It is very similar to that area in T. congolensis. The ventral process of the prefrontal and the anterior orbital margin are missing in both prefrontals in ANSP 15544. However, the right prefrontal has the dorsal orbital margin preserved as in T. congolensis.</p> <p>FRONTAL (figs. 168, 170)</p> <p>Preservation: Both frontals are nearly complete in ANSP 15544 and are visible dorsally and ventrally with clear sutures.</p> <p>Contacts: The frontal in Taphrosphys sulcatus, as preserved in ANSP 15544, only contacts the prefrontal anteriorly and the parietal posteriorly. However, on both sides the frontals and parietals show that a postorbital was present and contacted the posterolateral edge of the frontal. This contact, however, is much shorter in T. sulcatus and T. congolensis than in Azabbaremys.</p> <p>Structures: The frontal forms most of the dorsal orbital margin in Taphrosphys sulcatus, as in T. ippolitoi and most other bothremydids. When the orbit of T. sulcatus is restored on the basis of the curvature seen in ANSP 15544, the size is consistent with what could be restored for T. ippolitoi and T. congolensis based on different combinations of preserved elements. However, there is no one skull of Taphrosphys that has the orbit completely preserved, and the size and shape could vary among the three species.</p> <p>PARIETAL (figs. 168, 170, 172, 173)</p> <p>Preservation: Both parietals in ANSP 15544, the best skull roof for Taphrosphys sulcatus, are present and complete with no distortions except for the lateralmost margins, which are missing, and nearly all of the processus inferior parietalis, which is also gone on both sides. A partial skull, YPM PU 18707, has part of the left parietal preserved but it is much less complete than ANSP 15544. Another more complete skull, NJSM 11362, has both parietals present. These are complete dorsally and have good contacts with the supraoccipital, but they also lack most of the processus inferior parietalis on both sides.</p> <p>Contacts of dorsal plate: In Taphrosphys sulcatus only the anterior contact with the frontal and the posteroventral contact with the supraoccipital are preserved.</p> <p>Structures of dorsal plate: The posterior edge of the parietal in Taphrosphys sulcatus that forms the edge of the temporal emargination is preserved in both ANSP 15544 and NJSM 11362, but it is more complete in the latter. The degree of emargination in T. sulcatus is consistent with T. ippolitoi and is very similar to that in T. congolensis. The emargination limits are not determinable in T. sulcatus, as they are in T. congolensis. However, the emargination seems to be slightly wider in T. congolensis than in T. sulcatus because the parietal dorsal plate is slightly wider in T. sulcatus than in T. congolensis. The parietal margin of the temporal emargination in T. sulcatus appears to be straight or slightly convex laterally. The parietal on the midline extends posteriorly to the supraoccipital, being exposed in dorsal view as a small triangular or oblong shape.</p> <p>Contacts of processus inferior parietalis: In Taphrosphys sulcatus, NJSM 11362 has enough of the foramen nervi trigemini on the pterygoid and prootic preserved to show that the parietal contacted those bones on either side of the foramen and made up its anterodorsal margin. The processus inferior parietalis also contacted the crista pterygoidea, as seen in NJSM 11362 and YPM PU 18707.</p> <p>Structures of processus inferior parietalis: In Taphrosphys sulcatus only the very dorsal portion of this wall can be seen in ANSP 15544 and NJSM 11362. It is nearly identical to that in T. congolensis.</p> <p>JUGAL</p> <p>Preservation: Among the specimens identifiable as Taphrosphys sulcatus, there is no jugal. Due to the absence of the other palatal elements, maxilla, palatine, as well as cheek elements, it is not possible to find an adjacent bone articulating with the jugal.</p> <p>QUADRATOJUGAL</p> <p>Preservation: The element is absent in all available specimens of Taphrosphys sulcatus.</p> <p>SQUAMOSAL (figs. 168, 169, 176, 177)</p> <p>Preservation: The nearly complete right squamosal is present in NJSM 11362. It lacks its anteriormost margin and a small section of the posterior margin. ANSP 15544 has a right squamosal that is complete except for its ventral margin and its anteriormost edge.</p> <p>Contacts: The squamosal has the same contacts on all three Taphrosphys species: it lies on the quadrate, contacting it anteriorly and anteromedially, and it contacts the opisthotic medially and the quadratojugal anterodorsally.</p> <p>Contacts and structures: The only information on the postorbital in Taphrosphys sulcatus relates to the sutured edges on the frontals and parietals in ANSP 15544. These are consistent with a postorbital that is the same size and shape as the ones in T. congolensis and T. ippolitoi.</p> <p>Structures: The antrum postoticum in Taphrosphys sulcatus is particularly visible in ANSP 15544, which includes a disarticulated right quadrate and right squamosal (fig. 176). The antrum itself is described under Quadrate, but its posterior cap is formed by the squamosal and can be seen in this specimen. In most turtles the antrum postoticum is a large cavity surrounded by relatively thin walls. In many bothremydids the antrum is small or absent. In Taphrosphys it is much smaller than in pelomedusids and smaller than in Galianemys, but it is still distinct. The removable right squamosal of ANSP 15544 shows that even though the antrum is reduced almost to a canal, it still significantly affects the formation of the squamosal and forms a smooth, hemispherical pocket that surrounds the tubelike extension of the quadrate.</p> <p>The squamosal of Taphrosphys sulcatus, seen in NJSM 11362 (fig. 177), has a distinct ventral flange developed to about the same extent as in T. congolensis, both of which are smaller than in T. ippolitoi. Although the posterior margins of all the T. sulcatus squamosals are broken, they are very thin, and a posterior extension of the sort seen in Labrostochelys was not present.</p> <p>POSTORBITAL</p> <p>Preservation: Although one was almost certainly present, there is no postorbital in any available specimen of Taphrosphys sulcatus.</p> <p>PREMAXILLA (figs. 168, 169, 171)</p> <p>Preservation: The available material of Taphrosphys sulcatus lacks all the bones of the palate except for a single premaxilla, the left one, in YPM PU 18707. This element lacks its posterior plate.</p> <p>Contacts and structures: The premaxilla in YPM PU 18707 is very similar to the better preserved premaxilla in the other Taphrosphys species, except that the labial ridge is deeper in T. congolensis than in T. sulcatus and T. ippolitoi. See T. ippolitoi description for more information on the Taphrosphys premaxilla.</p> <p>MAXILLA</p> <p>Preservation: Although one was almost certainly present, there is no maxilla in any of the available Taphrosphys sulcatus.</p> <p>VOMER Preservation: The vomer is missing.</p> <p>PALATINE</p> <p>Preservation: Although one was almost certainly present, it is not preserved in the available specimens of Taphrosphys sulcatus.</p> <p>QUADRATE (figs. 168, 169, 172, 173, 176, 177)</p> <p>Preservation: Partial left and right disarticulated quadrates of Taphrosphys sulcatus are present in ANSP 15544, and a nearly complete right quadrate is in NJSM 11362.</p> <p>Contacts on lateral surface: All three Taphrosphys sulcatus quadrates completely lack the anterior part of the bone, and the only suture visible in lateral view is the posterior one with the squamosal, which is the same as in the other two Taphrosphys species.</p> <p>Structures on lateral surface: The cavum tympani in Taphrosphys is distinctly oval or kidney bean-shaped, not circular as in Azabbaremys and Phosphatochelys. T. sulcatus shows this shape, as do the other two Taphrosphys species. In T. sulcatus the cavum is slightly deeper than in T. congolensis,</p> <p>particularly the anteroventral part of the concavity. The incisura columellae auris in all Taphrosphys and in all Taphrosphyini is a round canal well separated by bone from the eustachian tube groove. In T. sulcatus there is a barely discernable groove from the incisura to the eustachian groove; a similar groove is in T. congolensis. However, in T. ippolitoi the groove is well defined by two parallel ridges, similar to the condition in Galianemys.</p> <p>The antrum postoticum in Taphrosphys sulcatus is smaller than in pelomedusids and is similar in size to that in Phosphatochelys. The antrum in T. ippolitoi is slightly smaller than in T. sulcatus; the T. congolensis quadrates are crushed down to the level of the antrum so that neither is visible. In T. sulcatus the antrum postoticum is close to the lateral edge of the quadrate, as in Phosphatochelys, but in T. ippolitoi the antrum is placed more deeply in the cavum tympani, presumably because the cavum is deeper.</p> <p>Although the anterior part of the cavum tympani is missing in all Taphrosphys sulcatus specimens, and the upper part of the cavum is crushed in T. congolensis, comparison can still be made with T. ippolitoi. In the former two species the cavum is about as deep as in Phosphatochelys and Galianemys, but in T. ippolitoi the cavum tympani is about double the depth. This affects the entire area of the cavum so that there is a large dorsal overhang and a large shelf ventrally.</p> <p>The eustachian tube in bothremydids (except for Foxemys, Cearachelys, and Polysternon) is separated by a solid bony wall from the stapes. A notch, the sulcus eustachii, carries the tube into the cavum tympani medial to the tympanic membrane. This notch is formed by the quadrate, and in Taphrosphys sulcatus and T. congolensis it opens directly ventral to the incisura columellae auris. In T. ippolitoi the notch opens posteroventrally at an angle to the incisura. The eustachian tube notch in T. sulcatus and T. congolensis is more open, but in Taphrosphys ippolitoi there is a flange of quadrate projecting posterodorsally from the lower edge of the notch that partially closes the notch.</p> <p>Contacts on dorsal and anterior surfaces: The dorsal contacts of the quadrates are the same in all three Taphrosphys species and in the Taphrosphyini: prootic anteromedially, opisthotic posteromedially, and squamosal posterolaterally. There is no quadrate-supraoccipital contact.</p> <p>Contacts on ventral surface: The quadrate in all three Taphrosphys species contacts the opisthotic posteromedially, the squamosal posterolaterally, the pterygoid anteromedially, the basisphenoid medially, and the basioccipital posteromedially. In T. ippolitoi and T. congolensis there is a posteromedial contact with the exoccipital just behind the basioccipital. In T. sulcatus, ANSP 15544, this part of the quadrate is broken off, but an exoccipital contact was likely based on the articulated basioccipital and exoccipitals of YPM PU 18707, which show a contact area for the quadrate on the exoccipital.</p> <p>Structures on ventral surface: The quadrate structures in ventral view are also very similar in the three Taphrosphys species. The foramen posterius canalis carotici interni is formed at the junction of the quadrate, basisphenoid, and pterygoid. The foramen is clear in T. ippolitoi (fig. 277D) and T. sulcatus, but the margins are eroded in T. congolensis. Nonetheless, small edges of the foramen are visible and the canalis caroticus internus can be followed to this point. There is no pterygoideus muscle attachment scar (as seen in some other bothremydids like Arenila) in any of the three Taphrosphys species. The condylus mandibularis is positioned well anterior to the condylus occipitalis.</p> <p>Structures on posterior surface: The fenestra postotica (fig. 177) is intact and uncrushed on the right side of NJSM 11362 in Taphrosphys sulcatus, on the right side of AMNH 30042 in T. ippolitoi, and on the left side of T. congolensis. In T. sulcatus and T. congolensis the fenestra is figure eight-shaped, an oval pinched in the center to separate the more dorsal stapedial artery from the more ventral lateral head vein. In the right side of T. congolensis, broken bone fragments separate the two parts into foramina, but this seems to be due to partial crushing. In T. ippolitoi, however, the fenestra is subdivided by bone that appears to be uncrushed and in its original condition. The quadrate in Taphrosphys as in other turtles forms the ventral part of the fenestra postotica, with the opisthotic forming the dorsal part. In T. ippolitoi the quadrate forms the process dividing it into two foramina.</p> <p>In the three species of Taphrosphys there is a variably developed ridge on the posterior surface of the processus articularis of the quadrate. This ridge extends from the ventral part of the processus dorsomedially to the base of the processus and may have formed a concavity for the depressor mandibulae attachment. The ridge is larger and more massive in T. ippolitoi but it is well developed in T. sulcatus, although incompletely preserved. Both have a shallow, ventrally facing trough formed by the ridge. In T. congolensis the ridge is much less prominent, possibly exaggerated by crushing of this part of the processus articularis. A similar ridge and trough is present in Labrostochelys; a rudimentary one is in Phosphatochelys and Azabbaremys.</p> <p>PTERYGOID (figs. 168, 169, 172, 174, 177)</p> <p>Preservation: The right pterygoid in Taphrosphys sulcatus is preserved in NJSM</p> <p>11362 and in YPM PU 18707. Both are uncrushed and free of matrix on all sides, but they lack the processus trochlearis pterygoidei.</p> <p>Contacts on ventral surface: See Taphrosphys ippolitoi for description.</p> <p>Structures on ventral surface: See Taphrosphys ippolitoi for description.</p> <p>Contacts on dorsal surface: The areas of the anterior contacts of the processus trochlearis pterygoidei, the sulcus palatinopterygoideus, and the posterior wall of the fossa nasalis are either absent or badly damaged in all three Taphrosphys species. The parietal contacts the crista pterygoidea anteriorly. More posteriorly there is a quadrate contact behind the foramen nervi trigemini on the dorsal surface.</p> <p>Structures on the dorsal surface: The area of the processus trochlearis pterygoidei and sulcus palatinopterygoideus in Taphrosphys is either missing (T. sulcatus) or badly damaged (T. congolensis and T. ippolitoi), but enough of the parietal is preserved to show that the septum orbitotemporale was absent, as in Azabbaremys and Phosphatochelys.</p> <p>The disarticulated pterygoids (YPM PU 18707 and NJSM 11362) of Taphrosphys sulcatus allow description of the internal aspects of the dorsal pterygoid surface (fig. 174), some of which is also visible in T. congolensis. There is a prominent crista pterygoidea articulating with the processus inferior parietalis. This wall is relatively narrow, as in Azabbaremys and Phosphatochelys, not extending to the anterior portion of the pterygoid or involving the palatine. Lateral to the crista pterygoidea, near the palatine contact, is a small foramen, the foramen nervi vidiani, as in most other Pelomedusoides. Medial to the crista pterygoidea is the sulcus cavernosus, and medial to that, in the suture between pterygoid and basisphenoid, is the canalis caroticus internus leading to the foramen posterius canalis carotici interni.</p> <p>In Phosphatochelys, four bones make up the foramen nervi trigemini: parietal, prootic, pterygoid, and quadrate. In Taphrosphys congolensis at least the prootic and pterygoid enter the margin (preserved only on the right side) with possibly the quadrate, with the parietal being uncertain. In T. sulcatus the pterygoid clearly makes up the ventral margin and the quadrate probably enters it, but the prootic and parietal contributions are not determinable. Although the foramen stapedio-temporale is very close to the foramen nervi trigemini in Taphrosphys, its exact margins are ambiguous, except in T. ippolitoi, AMNH 30500. In this specimen, the foramen nervi trigemini and foramen stapedio-temporale are joined by the same outer rim formed by the parietal, prootic, pterygoid, and quadrate. This is quite different from the situation in Phosphatochelys and Labrostochelys in which the two foramina are very close but not actually fused. A thin sheet of prootic separates the two foramina, but it lies posterior to the outer rim.</p> <p>SUPRAOCCIPITAL (figs. 168, 170, 172)</p> <p>Preservation: A complete supraoccipital in Taphrosphys sulcatus is preserved in NJSM 11362 and a nearly complete one is in ANSP 15544.</p> <p>Contacts: All three Taphrosphys species have these contacts: parietals dorsally, prootic anterolaterally, opisthotic laterally, and exoccipital posteroventrally. There is no quadrate contact.</p> <p>Structures: The crista supraoccipitalis is short in Taphrosphys sulcatus, as in Azabbaremys and Phosphatochelys. Although in T. congolensis the margin is broken, it is thin and unlikely to be more extensive than in T. sulcatus. In T. ippolitoi its length is indeterminate.</p> <p>EXOCCIPITAL (figs. 168, 172, 175, 177)</p> <p>Preservation: Both exoccipitals in Taphrosphys sulcatus are preserved in NJSM 11362 and are prepared on all surfaces and completely visible. However, both have a small portion of the ventrolateral process broken. YPM PU 18707 has both exoccipitals, which are complete and visible ventrally but lack the dorsal processes.</p> <p>Contacts: The contacts are the same in all three Taphrosphys species: supraoccipital dorsally, opisthotic laterally, quadrate ventrolaterally, basioccipital ventrally, and the other exoccipital ventromedially.</p> <p>Structures: In all three Taphrosphys species the exoccipitals meet on the midline to form the condylus occipitalis and its neck in ventral view. Dorsally, the contact extends farther anteriorly to exclude the basioccipital from the floor of the foramen magnum. This is similar to the Azabbaremys condition, but Phosphatochelys has the basioccipital separating the exoccipitals to a slightly greater degree.</p> <p>All three species of Taphrosphys have two pairs of the foramen nervi hypoglossi that penetrate the exoccipital (figs. 175, 177), with the more medial foramen being slightly larger than the more lateral one. The foramen jugulare posterius is completely enclosed, formed medially by the exoccipital and laterally by the opisthotic in all three species. The more lateral foramen nervi hypoglossi actually opens in the medial wall of the foramen jugulare posterius in all three Taphrosphys species, as it does in Phosphatochelys.</p> <p>BASIOCCIPITAL (figs. 168, 169, 175)</p> <p>Preservation: The complete basioccipital in Taphrosphys sulcatus is present in YPM PU 18707 and NJSM 11362; both are visible dorsally and ventrally. In NJSM 11362 the posterolateral margins are eroded, but they are complete in YPM PU 18707.</p> <p>Contacts: The contacts are the same in all three Taphrosphys species: basisphenoid anteriorly, quadrate laterally, and exoccipitals posteriorly.</p> <p>Structures: The condylus occipitalis is discussed under Exoccipital. All three Taphrosphys species have a shallow median concavity that parallels the basisphenoid suture. It is developed to about the same extent in Taphrosphys as it is in Phosphatochelys. It is not as flat as in Azabbaremys. The basioccipital of Taphrosphys also resembles Phosphatochelys in having a curved anterior margin rather than the straighter margin seen in Azabbaremys.</p> <p>The tuberculum basioccipitale in Taphrosphys ippolitoi is more distinct than in Azabbaremys, Phosphatochelys, or the other two Taphrosphys species. In T. ippolitoi the tuberculum, formed by basioccipital and exoccipital, extends posterolaterally to form a distinct shelf ventral to the foramen jugulare posterius. This is not developed in T. sulcatus or T. congolensis.</p> <p>PROOTIC (fig. 174)</p> <p>Preservation: In Taphrosphys sulcatus the right and left disarticulated and complete prootics are preserved in YPM PU 18707. The nearly complete right prootic is in NJSM 11362.</p> <p>Contacts: In all three Taphrosphys species there are the following contacts: parietal medially, quadrate laterally, supraoccipital posterodorsally, pterygoid ventrally, and opisthotic posteriorly.</p> <p>Structures: In Taphrosphys sulcatus, T. congolensis, and T. ippolitoi the prootic forms the lateral and dorsal part of the anterior-facing foramen stapedio-temporale. The more medial limits and the separation between the foramen stapedio-temporale from the foramen nervi trigemini, also roofed by the prootic, are not clear in T. sulcatus and T. congolensis. In T. ippolitoi these two foramina are fused into a common opening, in contrast to Phosphatochelys and Labrostochelys. The Taphrosphys sulcatus specimens show the internal features of the prootic, but they do not differ from other Pelomedusoides.</p> <p>OPISTHOTIC (figs. 168, 172, 174, 177)</p> <p>Preservation: In Taphrosphys sulcatus a nearly complete right opisthotic is present in NJSM 11362 and a nearly complete right opisthotic is present in YPM PU 18707.</p> <p>Contacts: In all three Taphrosphys species the contacts are: supraoccipital anteromedially, prootic anteriorly, quadrate anterolaterally and ventrally, squamosal posterolaterally, and exoccipital posteromedially.</p> <p>Structures: The dorsal surface is the same in all three Taphrosphys species and differs from Phosphatochelys and Azabbaremys only in having a more extended posterior process at the end of the opisthotic.</p> <p>On the ventral surface the opisthotic forms the roof of the fenestra postotica and the lateral wall of the foramen jugulare posterius. In all three Taphrosphys species the foramen jugulare posterius is closed by a process of the opisthotic contacting the dorsal and ventral margins formed by the exoccipital. The fenestra postotica in T. sulcatus and T. congolensis are figure eight-shaped openings with the dorsal half for the stapedial artery and the lateral head vein in the ventral half. The opisthotic forms most of the dorsal half and the quadrate the ventral half. In T. ippolitoi the fenestra postotica is divided by bone into two foramina, with the process being formed equally by opisthotic and quadrate, although there is cracking in this area and the quadrate alone may form the process.</p> <p>BASISPHENOID (figs. 168, 169, 174)</p> <p>Preservation: There is a nearly complete basisphenoid for Taphrosphys sulcatus showing both dorsal and ventral surfaces in NJSM 11362.</p> <p>Contacts: In all three Taphrosphys species the basisphenoid contacts are: pterygoid anterolaterally, quadrate laterally, and basioccipital posteriorly. The prootic should contact the basisphenoid laterally on its dorsal surface, and in T. congolensis crushed bone from the prootic does lie on the basisphenoid, but not in its original condition. In NJSM 11362 the ventromedial edge of the prootic has been lost, and no basisphenoid contact is present.</p> <p>Structures: In ventral view the basisphenoid is very similar in all three Taphrosphys species. The basisphenoid is five-sided in all three species, in contrast to the more triangular shape of Phosphatochelys, Azabbaremys, and Labrostochelys and to the V-shaped outline of Arenila. The dorsal surface is visible in all three Taphrosphys species. Beginning anteriorly on the basisphenoid, the anteriormost feature is the rostrum basisphenoidale, the ossification of the anterior portion of the trabeculae. In T. congolensis the rostrum is a laterally compressed process with a dorsal midline ridge, rather than being a cylinder commonly seen in other Pelomedusoides like Pelusios (fig. 24). In T. ippolitoi and T. sulcatus the midline area of the basisphenoid is flat, with no indication of an elongated or ridged rostrum basisphenoidale, a condition unusual for turtles. Directly posterior to the rostrum in T. congolensis is a well-defined oval depression, the sella turcica. Its floor is below the base of the rostrum basisphenoidale; there are deep lateral ridges and a high posterior dorsum sellae completely defining the deep sella turcica. This condition is more pronounced than in most turtles. In T. sulcatus and T. ippolitoi the sella turcica is a barely defined feature; there is only a low pair of anteromedial ridges along the basisphenoid-pterygoid suture, and a very low, nearly absent, dorsum sellae. Such a low and undefined sella turcica is unusual for turtles. The dorsum sellae of T. congolensis is high and nearly vertical. In T. sulcatus and T. ippolitoi it is a low, barely defined swelling. At the dorsolateral margin of the dorsum sellae in T. congolensis is the paired, relatively large, processus clinoideus, unusually well developed for a pelomedusoid. There is no sign of a processus clinoideus in T. sulcatus; however, some erosion has taken place here on both sides, and a pair could easily have been present, although not as large as in T. congolensis. In T. ippolitoi the processus is low on both sides. The foramen anterius canalis carotici interni in T. congolensis is closer to the midline than that foramen in T. sulcatus and T. ippolitoi. The foramen is also angled to face anteromedially in T. congolensis due to the narrow sella turcica, while in T. sulcatus and T. ippolitoi the foramen anterius canalis carotici interni faces anteriorly and is not contained in a narrow sella turcica.</p> <p>Taphrosphys ippolitoi</p> <p>This species of Taphrosphys is represented by a nearly complete skull (AMNH 30042) and a partial skull (AMNH 30500) that shows internal features of the braincase. Together, they make this species the most completely known of the genus.</p> <p>PREFRONTAL (figs. 178, 181, 183)</p> <p>Preservation: Both prefrontals of Taphrosphys ippolitoi are present in AMNH 30042 and AMNH 30500. In AMNH 30042 they are pushed ventrally away from their original position, almost completely collapsing the fossa nasalis. Their ventral surfaces cannot be seen. Sutural contacts are clear in both skulls. There is some distortion posterolaterally in AMNH 30500, and the ventral edges are broken in AMNH 30500.</p> <p>Contacts: As in other bothremydids, the prefrontal in Taphrosphys ippolitoi contacts the other prefrontal medially, the frontal posteriorly, and the maxilla ventrolaterally. In AMNH 30042 both prefrontals are in roughly life position, but they have been separated from their original contacts.</p> <p>Structures: The dorsal plate of the prefrontal in Taphrosphys ippolitoi has the typical morphology seen in other Taphrosphyini, such as Azabbaremys. In T. ippolitoi the anterior margin of the prefrontal, which forms the dorsal edge of the apertura narium externa, is more protuberant than in T. sulcatus, T. congolensis, or Azabbaremys. The prefrontal in all three Taphrosphys species is thick on the midline, as in Azabbaremys and in contrast to Galianemys. In T. ippolitoi, however, the bone thickens anteriorly so that the anterior projection has a swelling visible in dorsal view, being thickest on the midline. This is absent in T. sulcatus and T. congolensis, as well as in other bothremydids. The ventral surface of most of the prefrontal is visible in AMNH 30042 and shows the roof of the relatively large fossa nasalis characteristic of T. ippolitoi. The fossa is smaller in T. sulcatus and T. congolensis. The prefrontal in Taphrosphys ippolitoi forms the anterodorsal margin of the orbit, as in other Taphrosphys species.</p> <p>FRONTAL (figs. 178, 181, 183)</p> <p>Preservation: Both frontals of Taphrosphys ippolitoi are present in both specimens and are undistorted. There is some breakage posterolaterally. Although the frontals are in good shape in AMNH 30042, the palatines have been crushed dorsally and obscure the posteroventral morphology of the sulcus olfactorius of the frontals, but this is visible in AMNH 30500.</p> <p>Contacts: The frontal in Taphrosphys ippolitoi has these common bothremydid contacts: frontal on midline, prefrontal anteriorly, and parietal posteriorly. AMNH 30500 lacks postorbitals. The usual postorbital contact posterolaterally is obscured in AMNH 30042 due to breakage of both frontal and parietal and the apparent absence of the postorbital due to breakage. Although the space between the jugal and parietal seems to require a postorbital in the orbital margin, whether it contacted the frontal is unclear. There is a postorbital-frontal contact in T. congolensis and T. sulcatus.</p> <p>Structures: The frontal forms most of the dorsal orbital margin in Taphrosphys ippolitoi, as in T. sulcatus. The margin is slightly eroded on both sides, and the shape of the orbit is not completely determinable. However, it is consistent with the orbital edge preserved in T. sulcatus. In Azabbaremys the frontal forms much less of the margin than in Taphrosphys.</p> <p>The ventral surface of the frontal in Taphrosphys ippolitoi shows a well-defined sulcus olfactorius formed by a deep parasagittal ridge that increases in height posteriorly to merge with the processus inferior parietalis. The sulcus olfactorius ridge in T. ippolitoi is somewhat deeper than that in Azabbaremys and much deeper than that in Galianemys. The ridge in T. ippolitoi is also deeper than that in T. sulcatus. The frontal is unknown in T. congolensis.</p> <p>PARIETAL (figs. 178, 181, 183)</p> <p>Preservation: Both parietals are present in AMNH 30042 but both are damaged by breakage, particularly distally. Both also show some dislocation. Significant distortion seems to be absent, the sutures are clear, and only the dorsal surface is visible. In AMNH 30500 both parietals are nearly complete and visible dorsally and ventrally.</p> <p>Contacts of dorsal plate: In the available material of Taphrosphys ippolitoi, the parietal in AMNH 30042 contacts the frontal anteriorly, the other parietal medially, and the supraoccipital posteromedially and ventrally, all as in other bothremydids. As preserved, the right parietal is overlapped by the right jugal anterolaterally, and the left parietal is near the left jugal. However, we have concluded that this is a result of crushing and considerable loss of height of the skull. Conservative restoration (fig. 178) strongly supports the interpretation that another bone was anterolateral to the parietal, presumably the postorbital. The parietal in Taphrosphys ippolitoi contacts the thin quadratojugal laterally, as in T. congolensis.</p> <p>Structures of dorsal plate: The dorsal plate of the parietal in Taphrosphys ippolitoi has a shape that is very similar to that in T. congolensis and T. sulcatus. A very small section of the parietal-supraoccipital suture remains at the posterior edge of the skull roof in AMNH 30042.</p> <p>The surface of the parietal, frontal, and prefrontal of Taphrosphys ippolitoi in AMNH 30042 has a roughly corrugated texture, in contrast to the very smooth surface in T. sulcatus and T. congolensis. In AMNH 30500 the surface is slightly rugose, but not corrugated as in AMNH 30042. Scale sulci are not visible in any of the Taphrosphys skulls.</p> <p>Contacts of processus inferior parietalis: In Taphrosphys ippolitoi, AMNH 30500 has most of the processus inferior parietalis preserved. There is no palatine contact, but the usual, wide pterygoid contact extends posteriorly to the foramen nervi trigemini where the prootic contacts the parietal posteroventrally. Posteriorly the supraoccipital contacts the parietal.</p> <p>Structures of processus inferior parietalis: The processus inferior parietalis in Taphrosphys ippolitoi is wider than in Azabbaremys and Phosphatochelys. It forms the anterodorsal margin of the foramen nervi trigemini, which is nearly combined with the foramen stapedio-temporale. The combined foramina form the common margin of an oval opening, with a narrow sheet separating the two foramina, well posterior to the common margin.</p> <p>JUGAL (figs. 178, 181)</p> <p>Preservation: In Taphrosphys ippolitoi both jugals are present in AMNH 30042, and both are in roughly their original position. However, they have been slightly disarticulated and disturbed. The left one seems to be more complete and may not be missing anything but some edges. The right jugal is smaller and seems to have more broken edges and probably lacks larger areas. AMNH 30500 lacks jugals.</p> <p>Contacts of lateral plate: In Taphrosphys ippolitoi the left jugal in AMNH 30042 is in articulation with the maxilla anteroventrally in a suture that extends from the lower margin of the orbit to the maxilla-quadrate contact. On the right side in AMNH 30042, the jugal is displaced medially but the sutural surface is clear on the maxilla. Posteroventrally, the jugal contacts the quadrate, but it is displaced on the left side with some matrix in the jugal-quadrate suture. On the right side the jugal is more displaced and missing its posteroventral edge so that the jugal-quadrate suture is actually a narrow space.</p> <p>Structures of lateral plate: Posterodorsally the right jugal in Taphrosphys ippolitoi, AMNH 30042, contacts the parietal margin as preserved, but this is interpreted as due to postmortem crushing in which the postorbital and quadratojugal are either covered or missing. In the reconstruction the jugal only contacts the postorbital and quadratojugal along its dorsal margin. Unfortunately, neither the postorbital or quadratojugal is clearly preserved in the region of their contacts with the jugal. A postorbital-jugal contact is very likely because what seems to be that contact is preserved at least in part on both jugals. The jugal-quadratojugal contact, however, is more speculative because this area is not preserved in either skull. The jugal of Taphrosphys ippolitoi enters the posteroventral margin of the orbit, and this is preserved on both sides in AMNH 30042. As in T. congolensis, the quadrate-maxilla contact prevents a jugal exposure on the cheek.</p> <p>Contacts and structures of medial process: A portion of the medial jugal process in Taphrosphys ippolitoi is present on both sides of AMNH 30042, but displacement and breakage prevent a detailed description.</p> <p>QUADRATOJUGAL (figs. 178, 181, 183)</p> <p>Preservation: In AMNH 30042 the quadratojugal is completely missing on the left side, and only its narrow posterior extension is present on the right. In AMNH 30500, most of both quadratojugals are present.</p> <p>Contacts and structures: The quadratojugal in Taphrosphys ippolitoi contacts the quadrate ventrally in a wide suture and the squamosal posteriorly in a very narrow suture. It contacts the parietal medially and the jugal anteroventrally. The anterodorsal suture is very likely present but not clearly preserved.</p> <p>The quadratojugal forms part of the anterolateral edge of the temporal emargination. The quadratojugal in T. ippolitoi agrees with that in T. congolensis.</p> <p>SQUAMOSAL (figs. 178, 183, 184, 286E)</p> <p>Preservation: In Taphrosphys ippolitoi both squamosals are present in both skulls and they are nearly complete. In AMNH 30042 the left one is damaged dorsally and lacks the parasagittal ridge. Both lack part of the posterior margin. In AMNH 30500 the left one is broken dorsally.</p> <p>Contacts: As in Taphrosphys sulcatus.</p> <p>Structures: The antrum postoticum in Taphrosphys ippolitoi is preserved completely and prepared on the right side of AMNH 30042 and of AMNH 30500. It is similar in size and shape to that in T. sulcatus, but the lateral wall formed of quadrate plus squamosal is thicker in T. ippolitoi than it is in T. sulcatus. The ventral flange of the squamosal in Taphrosphys ippolitoi is deeper than in both T. sulcatus and T. congolensis. Its ventral margin is also curved medially in T. ippolitoi, rather than straight, as in T. sulcatus and T. congolensis. Although the posterior margin of the squamosal is slightly thicker than in the other two species, it does not extend posteriorly to a greater degree.</p> <p>POSTORBITAL (fig. 178)</p> <p>Preservation: Although one was almost certainly present in Taphrosphys ippolitoi, few of the fragments in the area of the postorbital can be clearly identified as such and none has clear contacts.</p> <p>Structures and contacts: In Taphrosphys ippolitoi both the jugal and parietal on the left side and to some extent on the right side of AMNH 30042 preserve contacts that are best interpreted as postorbital sutures. The reconstruction hypothesizes a postorbital very similar to that in T. congolensis with a narrow frontal contact, a long orbital margin exposure, and a long jugal contact. AMNH 30500 preserves what are probably the postorbital contact on the anterolateral margin of both parietals and the posterior contact with both quadratojugals, so the contacts and shape of the postorbital can be determined. There is no sign of a medial process of the postorbital in Taphrosphys ippolitoi; the medial process of the postorbital seems to be absent in the other Taphrosphys species.</p> <p>PREMAXILLA (figs. 178, 179, 181)</p> <p>Preservation: Both premaxillae are present in AMNH 30042: the left one is complete, and the right one lacks a small portion of the posterior plate. Premaxillae are missing in AMNH 30500.</p> <p>Contacts: In Taphrosphys ippolitoi the midline contact is completely preserved for the full length of the element, and there is a presumed contact edge for the vomer, which is missing. Posterolaterally the premaxilla contacts the maxilla in a suture that is comparable in height to that in T. congolensis (the contact in T. sulcatus is not completely preserved).</p> <p>Structures on dorsal surface: The premaxilla forms the floor of the apertura narium externa, which can be entirely reconstructed in Taphrosphys ippolitoi and partially in the other two Taphrosphys species. The apertura in T. ippolitoi is significantly wider than in the other two species, withmuch of the width being formed by a broader premaxilla. The floor of the fossa nasalis is also broader and deeper in T. ippolitoi than in the other two species.</p> <p>Structures on ventral surface: In ventral view the premaxilla of Taphrosphys ippolitoi forms the medial portion of the triturating surface. Due to its greater width, it forms more of this surface in T. ippolitoi than in the other Taphrosphys species. The labial ridge in T. ippolitoi is similar to that in T. sulcatus, both of which are shallower than in T. congolensis. The anterior part of the triturating surface in T. ippolitoi is wider than in the other two species. The medial edge of the triturating surface is a very low ridge separating the nutrient-rich surface from the smooth medial area. This medial area is a shallow concavity; the comparable area is missing in T. congolensis and T. sulcatus. Near the posterior edge is the foramen praepalatinum, completely formed by the premaxilla in T. ippolitoi.</p> <p>MAXILLA (figs. 178, 179, 181)</p> <p>Preservation: Both maxillae are preserved and are nearly complete and uncrushed in AMNH 30042, although they are slightly displaced from their original positions. Maxillae are missing in AMNH 30500.</p> <p>Contacts of vertical plate: The maxilla of Taphrosphys ippolitoi contacts the premaxilla anteriorly and the prefrontal anterodorsally. Posterodorsally there is a clear contact with the jugal that seems to exclude any contact with the postorbital. Posteriorly, below the jugal contact there seems to be a quadrate contact, although it is not present on either side as preserved. On the left side there is obvious displacement, but the maxilla and quadrate are very close nonetheless. In the restoration it is difficult to bring the surrounding elements into position without a strong maxilla-quadrate contact. There is no quadratojugal contact.</p> <p>Structures of the vertical plate: The apertura narium externa lateral margins are slightly flared laterally in Taphrosphys ippolitoi, in contrast to T. congolensis in which they lie in the plane of the rest of the maxilla. The entire anterior half of the maxilla in T. ippolitoi is expanded laterally so that the snout is flared, in contrast to the more acute snout of T. congolensis and, presumably, T. sulcatus. In T. sulcatus the small premaxilla suggests a narrower snout, more like T. congolensis than T. ippolitoi.</p> <p>Contact of horizontal plate: Very little of the dorsal surface of the fossa orbitalis is visible in Taphrosphys ippolitoi, so the elements making up the floor of the fossa orbitalis are not determinable. See T. congolensis for other contacts.</p> <p>Structures of horizontal plate: The triturating surface of the maxilla in Taphrosphys ippolitoi has an acute, relatively deep labial ridge with a broadly curved medial surface, similar to that in Labrostochelys. This is in contrast to the medial surface meeting the labial ridge at right angles, as in Azabbaremys. The maxillary triturating surfaces of T. ippolitoi and T. congolensis are very similar, with T. ippolitoi being slightly more expanded anteriorly.</p> <p>VOMER</p> <p>Preservation: The vomer is missing in both skulls of Taphrosphys ippolitoi, but a sutural margin on the posterior edge of the left premaxilla in AMNH 30042 suggests that one was present.</p> <p>PALATINE (figs. 178, 179, 181)</p> <p>Preservation: Both palatines are present and nearly complete in AMNH 30042, although both lack their anterior margins. Both are fractured and pushed dorsally above the level of the pterygoids. Palatines are missing in AMNH 30500.</p> <p>Contacts: Both Taphrosphys ippolitoi and T. congolensis specimens show the palatine contacting the maxilla anterolaterally, the other palatine medially, and the pterygoid posteriorly. There is probably a lateral contact with the jugal, but it is either disarticulated (T. ippolitoi) or missing (T. congolensis). The possible vomer contact is not preserved in either specimen. The dorsal surface contacts are not visible in either T. ippolitoi or T. congolensis.</p> <p>Structures: The palatines of Taphrosphys ippolitoi and T. congolensis are very similar in shape and size. The palatine in both species does not enter onto the triturating surface to a significant extent, in agreement with other Taphrosphyini. Both species also lack the strong dorsal arching of the palatine seen in Azabbaremys and Phosphatochelys.</p> <p>QUADRATE (figs. 178, 183, 184, 286E)</p> <p>Preservation: In AMNH 30042 both quadrates are present and nearly complete although fractured. There is some ventral displacement of the dorsal part, particularly in the left quadrate. Both quadrates lack the anterodorsal sutural edge. In AMNH 30050, both quadrates are uncrushed and complete, except for their anterior margins.</p> <p>Lateral view contacts and structures: The maxilla-quadrate contact of</p> <p>Taphrosphys ippolitoi is described under Maxilla, and the quadrate is described under T. sulcatus.</p> <p>Dorsal view contacts and structures: See Taphrosphys sulcatus for description.</p> <p>Ventral view contacts and structures: See Taphrosphys sulcatus for description.</p> <p>PTERYGOID (figs. 178, 179, 181, 277D)</p> <p>Preservation: Both pterygoids are present in AMNH 30042, but they are visible only in ventral view. Each pterygoid is also nearly complete except for some fractures and the broken processus trochlearis pterygoidei, which is on each side, although displaced. In AMNH 30500, both pterygoids are present but lack their anterior area and processus trochlearis pterygoidei. The dorsal surface is visible.</p> <p>Contacts on ventral surface: In all three Taphrosphys species these contacts are the same: palatine anteriorly, other pterygoid anteromedially, basisphenoid posteromedially, and quadrate posterolaterally. The pterygoids in Taphrosphys are not as completely separated by the basisphenoid as in Azabbaremys and Phosphatochelys.</p> <p>Structures on ventral surface: Although at least part of the processus trochlearis pterygoidei is present in Taphrosphys congolensis and T. ippolitoi (but not T. sulcatus), the angle or relative size is not determinable. The quadrate ramus of the pterygoid is preserved in all three Taphrosphys species and is very similar to that in Azabbaremys and Phosphatochelys. There is no depression or attachment scar for the pterygoideus musculature as seen in Arenila. The foramen posterius canalis carotici interni is formed equally by the pterygoid, basisphenoid, and quadrate in all three Taphrosphys species (fig. 277D). The edges of this foramen are slightly eroded in T. congolensis and T. sulcatus, but it is well preserved on the left side of AMNH 30042, T. ippolitoi. In AMNH 30500, the foramen posterius canalis carotici interni is formed mostly by the basisphenoid and quadrate, with the pterygoid nearly squeezed out. The foramen in AMNH 30042 is at the bottom of a slight depression that angles dorsomedially. There is no evidence that the pterygoid in any Taphrosphys species forms part of the foramen palatinum posterius.</p> <p>Contacts on dorsal surface: See Taphrosphys sulcatus for description.</p> <p>Structures on dorsal surface: See Taphrosphys sulcatus for description.</p> <p>SUPRAOCCIPITAL (figs. 178, 181)</p> <p>Preservation: In Taphrosphys ippolitoi in AMNH 30042, the anterior portion of the supraoccipital is largely covered by matrix, but the right portion is visible. The crista supraoccipitalis is broken at the foramen magnum. In AMNH 30500 the supraoccipital is entirely visible with clear sutures, but it also is missing nearly all of the crista supraoccipitalis.</p> <p>Contacts and structures: See Taphrosphys sulcatus for description.</p> <p>EXOCCIPITAL (figs. 178, 183, 184)</p> <p>Preservation: Both exoccipitals are preserved and nearly complete in both skulls of Taphrosphys ippolitoi.</p> <p>Contacts and structures: See Taphrosphys sulcatus for description.</p> <p>BASIOCCIPITAL (figs. 178, 179, 183, 184, 277D)</p> <p>Preservation: The basioccipital is complete and visible in ventral view in both skulls of Taphrosphys ippolitoi.</p> <p>Contacts and structures: See Taphrosphys sulcatus for description.</p> <p>PROOTIC (fig. 183)</p> <p>Preservation: Although both prootics are presumed to be present in Taphrosphys ippolitoi, they are completely covered in AMNH 30042. In AMNH 30500, both prootics are visible, well preserved, and have clear sutures.</p> <p>Contacts and structures: See Taphrosphys sulcatus for description.</p> <p>OPISTHOTIC (figs. 178, 183, 184)</p> <p>Preservation: In Taphrosphys ippolitoi in AMNH 30042, both opisthotics are present and nearly complete. The right is missing its posterior margin. Both are fractured on their dorsal surfacebut are in their original positions. Ventrally the right opisthotic is better preserved in the fenestra postotica region. In AMNH 30500 both opisthotics are complete with clear sutures.</p> <p>Contacts and structures: See Taphrosphys sulcatus for description.</p> <p>BASISPHENOID (figs. 178, 179, 183, 277D)</p> <p>Preservation: The basisphenoid is complete, in both AMNH 30500 and AMNH 30042 of Taphrosphys ippolitoi.</p> <p>Contacts and structures: See Taphrosphys sulcatus for description.</p> <p>Taphrosphys congolensis</p> <p>The single skull representing this species is crushed dorsoventrally, but during preparation, some of the skull roofing elements were removed, giving access to the internal basicranium and allowing reconstruction of the skull roof. Taphrosphys congolensis is weakly supported as the sister taxon to the other two Taphrosphys species. The type of this species is a shell, and this skull was apparently not found associated with a shell of Taphrosphys congolensis, it was only found in the same unit.</p> <p>PREFRONTAL (figs. 185, 188)</p> <p>Preservation: Only the left prefrontal in Taphrosphys congolensis is preserved, but it seems to be nearly complete. Although it is disarticulated and not in its original position with regard to the neighboring bones, the element itself appears to be uncrushed and not distorted. All of the dorsal and most of the ventral surfaces are visible.</p> <p>Contacts: The prefrontal of Taphrosphys congolensis as preserved lies on the internal surface of the maxilla and partially contacts the parietal posteriorly. These are not its original relations and are due to postmortem disarticulation and disturbance of this element. Sutural surfaces are clear for the usual bothremydid contacts: prefrontal medially, maxilla ventrolaterally, and frontal posteriorly.</p> <p>Structures: The prefrontal in Taphrosphys congolensis is very similar to that bone in Azabbaremys, T. ippolitoi, and T. sulcatus, although it is incomplete in the latter. Its surface is smooth and lacks the swelling seen in T. ippolitoi. The ventral surface of the prefrontal is largely visible in this specimen and shows the roof of the fossa nasalis, smaller than in T. ippolitoi but the same as in T. sulcatus. The midline suture is also visible, showing the bone to be much thicker on the midline than more laterally. Taphrosphys congolensis has a completely preserved ventral process of the prefrontal. This process forms most of the anterior orbital margin and a portion of the dorsal margin, a degree of orbital exposure also found in Azabbaremys.</p> <p>FRONTAL (fig. 185)</p> <p>Both frontals are completely missing in Taphrosphys congolensis. However, the preservation of the surrounding bones (prefrontal, parietal, and postorbital) gives a good idea of the position and shape of the frontal in T. congolensis.</p> <p>PARIETAL (figs. 185, 188)</p> <p>Preservation: Both parietals are preserved in Taphrosphys congolensis and are complete except for some missing edges laterally. The ventral and dorsal surfaces are visible on the right parietal, which has been removed from the rest of the specimen. The ventral edge and the contact of the processus inferior parietalis on both sides are either broken off (right) or crushed ventrally (left) and not visible.</p> <p>Contacts of dorsal plate: As preserved, the left parietal of Taphrosphys congolensis touches (but does not share a suture with) the left prefrontal. A frontal was originally between these two bones, and the present condition is due to postmortem disarticulation and disturbance. The right and left parietals overlie the respective postorbitals and quadratojugals, a condition that is interpreted as the result of postmortem disarticulation. However, the relative positions of these bones have not changed much from the life position, so that the parietal contacted the postorbital anterolaterally and the quadratojugal posterolaterally, as indicated in the restoration (fig. 185).</p> <p>The dorsal plate of the right parietal is more complete than the left one. The lateral edges are broken, but they very nearly fit with the associated postorbital and quadratojugal. Restored from these elements, the parietal has an anterolateral postorbital contact and a lateral quadratojugal contact. The postorbital contact is longer than the quadratojugal one. The other two Taphrosphys species are not well preserved in this area, but what is preserved in both is consistent with the condition in Taphrosphys congolensis.</p> <p>Structures of the dorsal plate: The dorsal plate of the parietal is nearly complete in Taphrosphys congolensis. The emargination extends about halfway anteriorly up the length of the parietal, in contrast to forms like Azabbaremys in which it extends for only about one-third the length. More of the otic chamber is also exposed, but the degree of emargination is less than in Galianemys and much less than in Kurmademys. The edge of the parietal forming the emargination in T. congolensis is nearly straight with a small bulge just anterior to the supraoccipital contact.</p> <p>Contacts of processus inferior parietalis: Although it is clear that most of the parietal contacted the crista pterygoidea in Taphrosphys congolensis as in all other turtles, the position of the foramen nervi trigemini and the bones forming it cannot be seen.</p> <p>Processus inferior parietalis: The dorsal parts of this wall are present on both sides, and the cavum cranii roof forming the cerebral expansions is visible. These are very similar in both Taphrosphys congolensis and T. sulcatus (indeterminate in T. ippolitoi). The processus inferior parietalis in T. congolensis and T. sulcatus is clearly wider than in Azabbaremys, which has an unusually narrow one.</p> <p>JUGAL (figs. 185, 188)</p> <p>Preservation: On the left side, a portion of what appears to be the jugal is preserved in Taphrosphys congolensis. Adjacent articulating elements (maxilla, quadrate, postorbital, and squamosal) provide some information on the jugal shape and contacts on the cheek. The medial process, however, is largely missing. On the right side a small fragment of what seems to be jugal is present between quadrate and postorbital.</p> <p>Contacts and structures of lateral plate: In Taphrosphys congolensis the jugal shape is based primarily on a reconstruction of the elements around it. There is some degree of guesswork involved in this reconstruction because few of the surrounding elements are themselves in their original positions.</p> <p>The maxilla-quadrate contact prevents a cheek exposure of the jugal, and the lower edge of the jugal contacts these two bones. The dorsal edge of the jugal contacts the postorbital anteriorly and the quadratojugal posteriorly. Presumably the jugal enters the orbital margin because a postorbital-maxilla contact, which would prevent that, is unlikely. However, none of the fragments possibly identifiable as jugal seems to have a natural edge. As reconstructed, the jugal in Taphrosphys congolensis is relatively long anteroposteriorly and short in height, similar to that bone in T. ippolitoi. It is possible that the jugal was nearly the same in both species, given the uncertainty of its shape in T. congolensis.</p> <p>QUADRATOJUGAL (figs. 185, 188)</p> <p>Preservation: Both quadratojugals are present in Taphrosphys congolensis. The right one is well preserved and in articulation with the postorbital and quadrate. The left one is fractured but complete and only slightly displaced anteriorly. Both have been pushed ventrally into the upper part of the quadrate. The left quadratojugal is fractured and partially distorted, but the right one appears to be in its original shape.</p> <p>Contacts: The quadratojugal in Taphrosphys congolensis has a long ventral suture with the quadrate and a shorter anterior suture with the postorbital. Dorsomedially there is a short contact, visible on the left side, with the parietal posterior to the postorbital. The quadratojugal in T. congolensis and T. ippolitoi does not extend ventrally along the anterior margin of the quadrate to reach the cheek margin due to a jugal-quadrate contact. However, there is not a complete dorsal restriction of the quadratojugal as seen in Phosphatochelys, which has a postorbital-quadrate contact, absent in Taphrosphys. The jugal-quadratojugal contact is not clearly preserved in T. congolensis, but there is a sutural margin preserved on the right quadratojugal that is best interpreted as this contact. The reconstruction is consistent with this interpretation (fig. 185). The posteriormost extension of the quadratojugal contacts the squamosal in a narrow suture above the quadrate.</p> <p>Structures: The quadratojugal in Taphrosphys congolensis is curved to cover the lateral part of the skull roof and part of the cheek. The right quadratojugal shows a well-preserved temporal margin just lateral to the parietal contact. The temporal emargination is formed laterally by the quadratojugal and part of the squamosal.</p> <p>SQUAMOSAL (figs. 185, 188, 189)</p> <p>Preservation: Both squamosals in Taphrosphys congolensis are present, uncrushed, and lack only their posterior margins.</p> <p>Contacts: As in Taphrosphys sulcatus.</p> <p>Structures: The antrum postoticum on the quadrate in Taphrosphys congolensis is crushed on both sides, so the internal structure of the antrum in the squamosal is not visible. The size and shape of the squamosal in T. congolensis are very similar in T. sulcatus. The ventral flange on the squamosal is nearly complete on the left side and is nearly identical to that in T. sulcatus.</p> <p>POSTORBITAL (figs. 185, 188)</p> <p>Preservation: Both postorbitals in Taphrosphys congolensis are preserved in their entirety, but they have been displaced ventrally from their original positions. Both are in roughly their original relations to other skull roof elements, and the right one is still articulated with the quadratojugal, further aiding in the reconstruction.</p> <p>Contacts: The postorbital of Taphrosphys congolensis contacts the quadratojugal posteriorly and the parietal medially. A short sutural margin anteromedially is interpreted as a frontal contact, and the ventral sutural margin is interpreted as the jugal contact.</p> <p>Structures: The anterior margin of the postorbital in Taphrosphys congolensis forms the posterior margin of the orbit. There is no exposure on the cheek or temporal emargination.</p> <p>An important feature of most pleurodire postorbitals is the medial process that forms much of the septum orbitotemporale. However, in Azabbaremys, Labrostochelys, and Phosphatochelys this process is absent and the wall is open. In Taphrosphys congolensis both postorbitals are dropped ventrally out of their original positions, but both are only fractured and not crushed or deformed. Some of their medial-ventral surface is also visible. Although the matrix has not been entirely removed, there is no sign of a medial process in either postorbital, and the condition is the same as in the other Taphrosphyini.</p> <p>PREMAXILLA (figs. 185, 186, 188)</p> <p>Preservation: The left premaxilla is present in Taphrosphys congolensis, uncrushed but lacking its posteromedial extension.</p> <p>Contacts: As in other bothremydids, the premaxilla of Taphrosphys congolensis meets the other premaxilla medially on the midline and the maxilla posterolaterally. The vomer and its presumed contact are missing.</p> <p>Structures: The labial ridge is preserved in all three Taphrosphys species. The ridge is relatively shallow in T. ippolitoi and T. sulcatus, both of which presumably had at least a slight notching or upswing to the labial ridge in anterior view. In contrast, T. congolensis has a deeper and more acute labial ridge that would not form a dorsal curve.</p> <p>MAXILLA (figs. 185, 186, 188)</p> <p>Preservation: Only the left maxilla is preserved; it is uncrushed but pushed medially out of its original position. Its dorsal margins are mostly broken.</p> <p>Contacts of vertical plate: The anteromedial contact with the premaxilla is present and intact. As preserved, despite being pushed medially, there is still a maxilla-quadrate contact posteriorly, and this is interpreted as original. The jugal is not present, but a short part of the jugal suture is interpreted as present. The anterodorsal suture with the prefrontal is partially preserved.</p> <p>Structures of vertical plate: The vertical plate forms the labial ridge in Taphrosphys congolensis and is similar to that in T. ippolitoi, but it curves anteromedially rather than flares laterally as in T. ippolitoi. The maxilla is missing in T. sulcatus.</p> <p>Contacts of horizontal plate: In both Taphrosphys ippolitoi and T. congolensis the maxilla has the same contacts: premaxilla anteromedially and palatine posteromedially. In both species the jugal (or a fragment of it) is present but displaced, still indicating the usual pelomedusoid posterolateral contact. Although it is not completely certain, a medially meeting process of the maxilla is unlikely in both T. congolensis and T. ippolitoi. In T. congolensis the medial margin of the maxilla seems to be complete enough to show that a process is absent. In T. ippolitoi the maxilla has a medial process, but it stops short of the midline due to the large premaxilla.</p> <p>Structures of horizontal plate: See Taphrosphys ippolitoi for description.</p> <p>VOMER</p> <p>Preservation: The vomer is missing in Taphrosphys congolensis.</p> <p>PALATINE (figs. 185, 186, 188)</p> <p>Preservation: In Taphrosphys congolensis the left palatine is nearly complete, lacking its anterior margin, but the right one is missing its anterior half. Both are slightly fractured but in their original positions.</p> <p>Contacts: See Taphrosphys ippolitoi for description.</p> <p>Structures: See Taphrosphys ippolitoi for description.</p> <p>QUADRATE (figs. 185–189)</p> <p>Preservation: Both quadrates are present in Taphrosphys congolensis with the ventral halves relatively well preserved, but both have the dorsal half of the cavum tympani and antrum postoticum crushed. The dorsomedial margins are mostly damaged or covered.</p> <p>Lateral view contacts and structures: The maxilla-quadrate contact is described under Maxilla, and the quadrate is described under Taphrosphys sulcatus.</p> <p>Dorsal view contacts and structures: See Taphrosphys sulcatus for description.</p> <p>Ventral view contacts and structures: See Taphrosphys sulcatus for description.</p> <p>PTERYGOID (figs. 185–189)</p> <p>Preservation: Both pterygoids in Taphrosphys congolensis are preserved in articulation, visible at least in part in dorsal as well as ventral view. The pterygoids are complete except for the processus trochlearis pterygoidei, which is missing in the left pterygoid and broken off but present, not in its original position, on the right side.</p> <p>Contacts on ventral surface: See Taphrosphys ippolitoi for description.</p> <p>Contacts on dorsal surface: See Taphrosphys sulcatus for description.</p> <p>Structures on dorsal surface: See Taphrosphys sulcatus for description.</p> <p>SUPRAOCCIPITAL (figs. 185, 188, 189)</p> <p>Preservation: The supraoccipital in Taphrosphys congolensis is crushed ventrally into the cavum cranii and is missing some of the edge of the crista supraoccipitalis, but the main body of the bone is relatively undistorted and well preserved although partially displaced from surrounding elements.</p> <p>Contacts and structures: See Taphrosphys sulcatus for description.</p> <p>EXOCCIPITAL (figs. 185, 188, 189)</p> <p>Preservation: Both exoccipitals in Taphrosphys congolensis are preserved and nearly complete although the supraoccipital has been crushed ventrally.</p> <p>Contacts and structures: See Taphrosphys sulcatus for description.</p> <p>(figs. 185–189)</p> <p>Preservation: The basioccipital in Taphrosphys congolensis is complete and visible in ventral view.</p> <p>Contacts and structures: See Taphrosphys sulcatus for description.</p> <p>PROOTIC</p> <p>Preservation: Both prootics are present in Taphrosphys congolensis, but only the right one is visible dorsally and anteriorly. It is partially disarticulated from surrounding elements and pushed ventrally.</p> <p>Contacts and structures: See Taphrosphys sulcatus for description.</p> <p>OPISTHOTIC (figs. 185, 186, 188, 189)</p> <p>Preservation: Both opisthotics are present and complete in Taphrosphys congolensis.</p> <p>Contacts of structures: See Taphrosphys sulcatus for description.</p> <p>BASISPHENOID (figs. 185, 186, 188)</p> <p>Preservation: The basisphenoid in Taphrosphys congolensis is complete with both dorsal and ventral surfaces visible.</p> <p>Contacts and structures: See Taphrosphys sulcatus for description.</p> <p>Labrostochelys galkini</p> <p>This unusual species is known from two skulls, one of which (AMNH 30043) is crushed but still well preserved and is the basis for most of the description and figures. Labrostochelys is the sister taxon to the remaining members of the subtribe Taphrosphyina.</p> <p>PREFRONTAL (figs. 190, 193)</p> <p>Preservation: Both prefrontals are present in AMNH 30043 and AMNH 29984, but they are more complete in the former. In both specimens the snout elements are displaced ventrally, and in AMNH 30043 they lie on the vomer. However, significant distortion does not seem to have taken place in either skull.</p> <p>Contacts: The prefrontal of Labrostochelys has the three usual contacts: prefrontal on midline, maxilla anteroventrolaterally, and frontal posteriorly. Because of its great length, the prefrontal and maxilla contacts are longer than in any other pleurodire. It is possible that the prefrontal contacted the premaxilla originally via a small anteroventral process that is now lost.</p> <p>The ventral process of the prefrontal is preserved on both sides of AMNH 30043. Despite some displacement of both bones, it is clear that although the prefrontal comes close to contacting the palatine as preserved, this was not the original condition. The palatine sutural edges match the maxilla sutural edges and the prefrontal seems to be completely excluded.</p> <p>Structures: The prefrontal of Labrostochelys is extremely long and narrow, longer and narrower than in any other turtle. It begins anteriorly at the apertura narium externa and extends posteriorly to the midpoint of the orbit, as in other Pelomedusoides. What in most other Pelomedusoides is a relatively short contact with the maxilla, in Labrostochelys it stretches for almost the entire length of the snout.</p> <p>At the anterior margin of the left prefrontal is a thin anterior process, broken anteriorly, that comes close to reaching a rugosity, possibly a suture, on a dorsal process of the premaxilla. It is possible that originally the prefrontal and premaxilla were in contact and divided the apertura narium externa on the midline. On the ventral surface, the posterior part of the prefrontal, which lies in the orbital margin, forms the anterior part of the sulcus olfactorius, much as in other Pelomedusoides such as Pelusios.</p> <p>FRONTAL (figs. 190, 193)</p> <p>Preservation: Both frontals are preserved in both specimens of Labrostochelys.</p> <p>30043 holotype with additions from AMNH 29984. [F. Ippolito, del.]</p> <p>Contacts: The frontal of Labrostochelys has the usual contacts: other frontal on midline, prefrontal anteriorly, postorbital posterolaterally, and parietal posteriorly.</p> <p>Structures: The frontal is widely exposed in the dorsal orbital margin in Labrostochelys, much as in Taphrosphys and in contrast to the smaller exposure in Azabbaremys. In AMNH 30043 some of the ventral surface of the frontal is visible and shows the sulcus olfactorius to be wide with deep ventral walls.</p> <p>PARIETAL (figs. 190, 193)</p> <p>Preservation: The anterior third or so of both parietals is present in AMNH 30043, with AMNH 29984 preserving much more of the temporal area but still missing the posterior parietal margins.</p> <p>Contacts of dorsal plate: As preserved, the parietal in Labrostochelys contacts the frontal anteriorly and the postorbital anterolaterally. Quadratojugal and squamosal contacts are indeterminable.</p> <p>Structures of dorsal plate: None of the temporal margin is preserved in either skull of Labrostochelys. However, natural edges of the quadrate and squamosal on the left side of AMNH 30043 show that the parietal roof was not extensive and probably did not extend posteriorly past the middle of the otic chamber. The skull roof in Labrostochelys, although elongate like the rest of the skull, was probably similar in temporal extent to that in Taphrosphys.</p> <p>Contacts of processus inferior parietalis: Much of the ventral process of the parietal is damaged in both skulls, but it can be seen that it has the usual long contact with the pterygoid and a posteroventral contact with the prootic and supraoccipital. A palatine contact at the anterior edge of the processus parietalis inferior is likely but not definite.</p> <p>Processus inferior parietalis: The parietal forms the anterodorsal edge of the foramen nervi trigemini, along with the prootic and pterygoid. Above the foramen the parietal forms a horizontal ridge that overhangs the foramen nervi trigemini and has a distinct, lateral process anterior to the foramen nervi trigemini. The ridge and process do not appear in any other pelomedusoid.</p> <p>JUGAL (figs. 190, 193)</p> <p>Preservation: Both jugals are present in both Labrostochelys skulls, somewhat disarticulated but in roughly their original positions.</p> <p>Contacts: The jugal in Labrostochelys contacts the maxilla anteroventrally, the quadratojugal posterodorsally, and the postorbital dorsally. These contacts are highly likely and only slightly disarticulated. As restored, the jugal contacts the quadrate and quadratojugal ventrally and does not enter the cheek margin. This is also likely because of a preserved maxilla-quadrate contact on the right side. The quadratojugal relations, however, are somewhat problematic, as the quadratojugal is preserved only as fragments in AMNH 30043. The quadratojugal probably does not reach the maxilla, but it is possible.</p> <p>Structures: The jugal in Labrostochelys forms the posteroventral margin of the orbit, as in Taphrosphys ippolitoi. The medial process of the jugal forms part of the floor of the fossa orbitalis, but none of the septum orbitotemporale, which is absent in Labrostochelys.</p> <p>QUADRATOJUGAL (figs. 190, 193)</p> <p>Preservation: The quadratojugal is missing in AMNH 29984 and only partially preserved in AMNH 30043. A narrow strip above the quadrate on the right side is quadratojugal, and on the left side a larger piece is present between jugal and quadrate.</p> <p>Contacts: As restored the quadratojugal of Labrostochelys contacts the postorbital anteromedially, the jugal anteroventrally, the squamosal posteriorly, and the quadrate ventrally. A parietal contact is possible but not determinable.</p> <p>Structures: The quadratojugal forms the posterolateral part of the skull roof emargination. Its medial extent is not determinable. The cheek area is disturbed in both skulls. As restored, the quadratojugal does not enter the cheek emargination, which is virtually absent in Labrostochelys.</p> <p>SQUAMOSAL (figs. 190, 191, 193, 287)</p> <p>Preservation: Little of the squamosal remains in AMNH 29984, but AMNH 30043 has nearly all of both squamosals.</p> <p>Contacts: The squamosal of Labrostochelys has the usual contacts: quadrate anteriorly, opisthotic medially, and quadratojugal anterodorsally. However, because of its unique shape, the squamosal contact with the quadrate is much longer than in other Taphrosphyini, resulting in a ventral quadrate process lying under the squamosal.</p> <p>Structures: Instead of the usual cone-shaped squamosal, Labrostochelys has a long, narrow squamosal developed into a vertical sheet forming a hornlike process at the back of the skull. This elongate squamosal is also seen in some trionychids, such as Cycloderma and Chitra (Gaffney, 1979a). The elongation is apparently related to jaw muscle attachments (Schumacher, 1973). The adductor mandibulae attaches on the medial and dorsal surfaces, with the depressor mandibulae attaching on the lateral and ventral surfaces. Interestingly, Labrostochelys also has a pocket on the posterior surface of the quadrate, another attachment site for the depressor mandibulae.</p> <p>The squamosal in Labrostochelys forms a small, lateral projection on its lateral surface near the quadrate contact (fig. 287). This is at the anterior margin of a curved ridge that separates the lateral surface from the dorsal surface and would appear to reflect the division of two muscle attachment sites. The antrum postoticum in Labrostochelys does not seem to extend into the squamosal in AMNH 30043, but it may in AMNH 29984 (see Quadrate).</p> <p>POSTORBITAL (figs. 190, 193)</p> <p>Preservation: The postorbital is present on both sides of AMNH 30043; the left is more complete, but neither includes the posterior limits. The right postorbital of AMNH 29984 is partially preserved.</p> <p>Contacts: The postorbital of Labrostochelys contacts the frontal anterodorsally, the parietal dorsomedially, the jugal anteroventrally, the pterygoid medially, and the quadratojugal posteroventrally. The extent of the posterior contacts is indeterminate.</p> <p>Structures: The postorbital in Labrostochelys forms part of the posterior orbital margin with less exposure than in Taphrosphys, Phosphatochelys, and Azabbaremys. Whether the postorbital extends posteriorly far enough to reach the temporal margin is not determinable, but it seems unlikely based on its preserved shape and similarity to Taphrosphys. In contrast to Phosphatochelys and Azabbaremys, there is a medial process of the postorbital forming at least a partial septum orbitotemporale and entering the sulcus palatinopterygoideus. This is only visible on the right side of AMNH 30043, and it is not well preserved.</p> <p>PREMAXILLA (figs. 190, 191, 193)</p> <p>Preservation: Both premaxillae are missing in AMNH 29984, but both are present and well preserved in AMNH 30043.</p> <p>Contacts: The premaxilla in Labrostochelys contacts the maxilla posterolaterally, the premaxilla medially, and the vomer posteromedially. The anterodorsomedial edge of the premaxilla in AMNH 30043 has a short dorsal process that may have contacted an anteroventral process of the prefrontal, producing a divided apertura narium externa. This condition is not found in other Taphrosphyini but is seen in some Bothremys.</p> <p>Structures: The premaxilla forms the ventral margin of the apertura narium externa and floor of the fossa nasalis. The apertura of Labrostochelys differs from the other Taphrosphyini in being much smaller and completely, or almost completely, divided on the midline. The uniquely narrow snout of Labrostochelys ends anteriorly in premaxillae that come to a blunt point, bearing the apertura narium externa at its end. The foramen praepalatinum on both premaxillae is incomplete, but it seems to have been formed entirely within the premaxilla, close to the midline suture but clearly separated from the vomer.</p> <p>On the ventral surface, Labrostochelys also differs from all other pleurodires in having a premaxilla that bears an elongation anterior to the labial ridge of the triturating surface. This triangular plate bears the floor of the fossa nasalis on its dorsal surface. Ventrally and around its edges are a large number of vascular foramina, indicating that it bore part of the horny beak like the rest of the triturating surface.</p> <p>The labial ridge is not a distinct ridge, but it forms a line where the flat anterior surface curves sharply dorsally to join the triturating surface proper. The posterior surface of the premaxilla forms a triangular shelf supporting the triturating surface. About midway along the surface, the premaxilla forms a midline concavity that is part of the roof of the mouth and leads into the apertura narium interna. The blunt ridge defining this concavity roughly parallels the labial ridge and may be interpreted as the lingual ridge. Laterally it is continuous with a more defined ridge on the maxilla that is clearly the lingual ridge.</p> <p>MAXILLA (figs. 190, 191, 193)</p> <p>Preservation: Both maxillae are present and nearly complete in both specimens.</p> <p>Contacts of vertical plate: In external view, the maxilla of Labrostochelys has the usual contacts: premaxilla anteromedially, prefrontal anterodorsally, and jugal posteroventrally, as in Taphrosphys and Azabbaremys. It is possible that there is a small quadratojugal contact between the jugal and quadrate. The length of the prefrontal-maxilla contact is unique in turtles.</p> <p>Structures of vertical plate: The dorsal process of the maxilla in Labrostochelys lies between the orbit and the apertura narium externa and is relatively distinct in shortsnouted forms like Phosphatochelys. In Labrostochelys, however, the area of the process is extremely lengthened and almost the same height as the posterior part of the bone so that the process is barely recognizable compared with other pleurodires. The maxilla forms the ventral margin of the orbit. Although the area is broken in AMNH 30043 and missing in AMNH 29984, there does not seem to be a cheek emargination, even a low one as in Taphrosphys.</p> <p>Contacts of horizontal plate: The usual contacts are present in Labrostochelys: premaxilla anteromedially, palatine posteromedially, and jugal posterolaterally. There is also a short vomer contact just behind the premaxilla anterior to the apertura narium interna. The jugal is slightly displaced on both sides of AMNH 30043 and AMNH 29984, but it seems to have only a short contact without the longer lateral contact usually seen in Pelomedusoides.</p> <p>In Labrostochelys the maxilla sends a small process medially to contact the vomer. Among the other Taphrosphyini, the vomer is unknown in Taphrosphys and Phosphatochelys, which could have had a contact. There is a contact in Nigeremys and Arenila, but not in Azabbaremys. As in Taphrosphys, the palatine does not extend into the area of the triturating surface.</p> <p>The dorsal surface of the maxilla is visible only to a limited degree in both Labrostochelys skulls, but it is clear that the maxilla does not contribute significantly to the floor of the fossa orbitalis. This is similar to the condition in Taphrosphys and Azabbaremys and in contrast to Phosphatochelys.</p> <p>Structures of horizontal plate: The ventral surface forms the triturating surface, which in Labrostochelys is relatively narrow and parallel-sided, similar to that in Taphrosphys in width. It is longer than in any Pelomedusoides due to the elongate snout. The labial ridge is deep and thin and curves evenly into the more horizontal part of the surface, in contrast to Azabbaremys and Phosphatochelys, which have an angled meeting, but very similar to T. ippolitoi. In Taphrosphys and Labrostochelys the maxillary part of the triturating surface is an inverted trough, unlike the morphology in other Pelomedusoides. The lingual ridge in Labrostochelys is low but distinct; still, it is slightly higher than in T. ippolitoi. The medial edge of the maxilla in Labrostochelys forms the apertura narium interna and, despite some breakage, seems to define a smaller apertura than in Taphrosphys, Phosphatochelys, and Azabbaremys.</p> <p>VOMER (figs. 190, 191, 193)</p> <p>Preservation: The vomer is present in AMNH 30043, but it is slightly displaced from its sutural contacts and is split anteriorly. Only the ventral surface is visible. The vomer is missing in AMNH 29984.</p> <p>Contacts: The vomer in Labrostochelys contacts the premaxilla anteriorly and the palatines posteriorly, as in all other Pelomedusoides in which it is known. Anterolaterally there is a short maxilla contact (see Maxilla).</p> <p>Structures: The vomer in Labrostochelys is long and narrow, not thick and short as in Nigeremys and Arenila. There is an expansion at both ends. The vomer does not participate in the foramen praepalatinum. The vomer forms the medial margin of the apertura narium interna, which in Labrostochelys is relatively small, smaller than in Azabbaremys and Phosphatochelys. None of the Taphrosphys skulls has well-preserved aperturae, but they seem to be larger than in Labrostochelys based on what is preserved.</p> <p>PALATINE (figs. 190, 191, 193)</p> <p>Preservation: Both palatines are present in both Labrostochelys skulls, but they are better preserved in AMNH 30043.</p> <p>Contacts: The palatine in Labrostochelys has the usual Pelomedusoides contacts: vomer anteromedially, maxilla anterolaterally, palatine medially, and pterygoid posteriorly. Although both the palatines and jugals are slightly disarticulated and displaced dorsally in both skulls, the usual dorsolateral contact with the jugal is present. A dorsal contact with the parietal is possible but not determinable.</p> <p>Structures on dorsal surface: The palatine in Labrostochelys forms nearly all of the floor of the fossa orbitalis, as in Taphrosphys but in contrast to Phosphatochelys, which has a much greater maxillary contribution. The foramen orbitonasale is mostly collapsed in both skulls, so it is present but cannot be easily compared with other taxa. The palatine forms the anterolateral edge of the apertura narium interna. This edge is broken so its original position is unknown, but what is preserved shows the apertura to be relatively small (see Maxilla). A dorsal process was probably not present, but the area is collapsed dorsally and not visible. If a process were present, it would probably cause some breakage or displacement through the thin palatine. The sulcus palatinopterygoideus is not well preserved, probably due to the absence of a postorbital wall, allowing dorsoventral crushing and collapse of the area.</p> <p>Structures on ventral surface: The palatine of Labrostochelys is similar to that bone in Taphrosphys, broadly curving dorsally into the apertura narium interna, but to a lesser degree than in Azabbaremys, Phosphatochelys, Nigeremys, and Arenila. There is no contribution of the palatine to the triturating surface. The foramen palatinum posterius is formed anteriorly by the palatine and posteriorly by the pterygoid. It is larger than in Phosphatochelys, Azabbaremys, and Taphrosphys and roughly similar to those in Nigeremys and Arenila.</p> <p>QUADRATE (figs. 190, 191, 193, 195, 277F, 287)</p> <p>Preservation: Both quadrates in AMNH 30043 are nearly complete. Both in AMNH 29984 are missing the anterior and dorsal areas.</p> <p>Lateral view contacts: In Labrostochelys the quadrate contacts the quadratojugal dorsally and anterodorsally and the squamosal posterodorsally. The squamosal contact (see Squamosal) is unusual in that the quadrate sends a process ventrally beneath much of the squamosal forming the greatly elongated posterior process. There is a maxilla-quadrate contact (see Maxilla); it is short, as in Taphrosphys congolensis. It is possible that there is a short jugal contact, as is likely in T. congolensis (see Jugal).</p> <p>Lateral view structures: The cavum tympani of Labrostochelys (fig. 287) agrees with other Taphrosphyini in being shallower than in the Pelomedusidae and generally agreeing with the Bothremydini. In Labrostochelys the depth of the cavum tympani varies between the two skulls, but in this case AMNH 29984 seems to be better preserved than AMNH 30043. The cavum tympani in AMNH 29984 is deeper than in AMNH 30043, about as deep as in Taphrosphys. The two skulls do differ in other features, so this may be individual variation rather than preservation. There is no fossa precolumellaris, and the cavum tympani is smoothly concave except for the antrum postoticum. The cavum tympani in Labrostochelys is slightly wider than high, agreeing with Taphrosphys (as restored, see Taphrosphys ippolitoi) and in contrast to Azabbaremys and Phosphatochelys, in which it is circular or slightly higher than wide.</p> <p>As in all other Taphrosphyini, Labrostochelys has a closed incisura columellae auris forming a bony canal for the stapes. There is a low groove extending posteroventrally from the incisura columellae auris to a notch on the edge of the quadrate for the eustachian tube, the sulcus eustachii. The sulcus in Labrostochelys has a short process extending ventrally (fig. 287), as in Phosphatochelys. There is no sign of a dorsal process as seen in Taphrosphys ippolitoi.</p> <p>The antrum postoticum in Labrostochelys differs between the two skulls. In AMNH 30043 it is about half the size of that in AMNH 29984. This does not seem to be a preservation or postmortem difference. In AMNH 29984 the antrum is about the size of the antrum in Phosphatochelys and Taphrosphys ippolitoi. In AMNH 29984 the opening of the antrum is oval, while in Taphrosphys and Phosphatochelys it is round. The antrum opening faces anterolaterally in both Labrostochelys skulls and anteriorly in Taphrosphys and Phosphatochelys. The antrum postoticum is absent in Azabbaremys and Nigeremys.</p> <p>The shelf formed along the ventrolateral margin of the cavum tympani that is un-</p> <p>[A. Venjara and E.S. Gaffney, del.]</p> <p>usually large and prominent in Taphrosphys ippolitoi is smaller in Labrostochelys as it is in Phosphatochelys.</p> <p>Contacts in dorsal view: In Labrostochelys the quadrate contacts vary on each side in AMNH 30043. On the right side it contacts the prootic anteromedially, the opisthotic posteromedially, and the squamosal posteriorly. These are the usual contacts in Taphrosphyini. On the left side, the squamosal has an anteromedial extension contacting the prootic, preventing a quadrate-opisthotic contact. This squamosal-prootic contact is unusual, possibly unique in turtles, and is interpreted as an individual variation. In AMNH 29984 the quadrate on the right side shows sutures, but the squamosal sutures are indistinct, so a squamosal-prootic contact cannot be determined.</p> <p>Dorsal view structures: As in the other Taphrosphyini, the foramen stapedio-temporale in Labrostochelys is at the anterior edge of the otic chamber, close to the foramen nervi trigemini.</p> <p>Ventral view contacts: As in the other Taphrosphyini, the quadrate of Labrostochelys contacts the pterygoid anteromedially, the basisphenoid medially, the basioccipital posteromedially, the exoccipital posteromedially (behind the basioccipital), and the squamosal posterolaterally. The basisphenoid and basioccipital contacts in Labrostochelys are narrower than in Taphrosphys, but similar in extent to Azabbaremys. The squamosalquadrate contact (see Squamosal) is uniquely long in Labrostochelys due to the posteriorly extended squamosal and a ventral quadrate process forming its ventral edge.</p> <p>Ventral view structures: The foramen posterius canalis carotici interni in Labrostochelys is formed within the quadrate, but the suture follows it posteriorly from the pterygoid suture, so it may be interpreted as being formed within the pterygoid-quadrate suture (fig. 277F). If interpreted this way it agrees with Azabbaremys and Phosphatochelys (indeterminate in Nigeremys). In Arenila it is between the basisphenoid and pterygoid. In Taphrosphys it is in the quadrate-pterygoid-basisphenoid suture.</p> <p>The fenestra postotica in Labrostochelys (fig. 195) is formed by the quadrate ventrolaterally and the opisthotic dorsomedially, as in Azabbaremys, Taphrosphys, and Phosphatochelys. The fenestra is elongate horizontally in Labrostochelys, rather than being elongate more vertically, as in Phosphatochelys and Azabbaremys. The stapedial artery portion lies directly lateral (rather than dorsal) to the lateral head vein portion. In Taphrosphys the fenestra is usually subdivided by bone, but the portions are more vertical than horizontal, as in Labrostochelys.</p> <p>The foramen chorda tympani inferius is a small hole on the posterior surface of the processus articularis. The posterior surface of the processus articularis in Labrostochelys has a posteroventrally opening concavity, similar to one seen in Taphrosphys ippolitoi (see Taphrosphys). This seems to be an attachment site for the depressor mandibulae (fig. 195). As in Taphrosphys, the condylus mandibularis in Labrostochelys is far anterior to the condylus occipitalis.</p> <p>PTERYGOID (figs. 190, 191, 193, 277F)</p> <p>Preservation: The pterygoids in AMNH 29984 are present but damaged anteriorly and laterally. In AMNH 30043, however, they are just superb! The pterygoid flange, a thin sheet often broken even in recent pleurodire skulls, and almost always damaged in fossils, is complete on both sides of AMNH 30043. The bones articulating anteriorly to the pterygoid have been dislocated and rudely shoved dorsally, but the posterior contacts are still intact.</p> <p>Contacts on ventral surface: The pterygoid in Labrostochelys has the usual Taphrosphyini contacts: palatine anteriorly, pterygoid anteromedially, basisphenoid medially, and quadrate posterolaterally. The pterygoid-pterygoid contact is very short, the same as in Arenila, much shorter than in Taphrosphys, but shorter than in all the other Taphrosphyini, except for Arenila. The anterolateral contact with the jugal is visible in ventral view.</p> <p>Structures on ventral surface: The processus trochlearis pterygoidei in Labrostochelys is very small and oriented posteriorly to an extent that it is not visible in ventral view. In the Taphrosphyini the processus is smaller than in many other pleurodires, but the condition seen in Labrostochelys is not even approached in other Pelomedusoides. In some chelids, such as Chelus and Chelodina (Gaffney, 1979a), the processus is also oriented posteriorly and relatively small, but in none is the processus as small as it is in Labrostochelys. The processus trochlearis pterygoidei in Labrostochelys parallels the edge of the pterygoid web or flange and trends slightly laterally rather than being completely parasagittal as in some chelids.</p> <p>The tubelike channel found in Phosphatochelys extending anterodorsally from the processus articularis of the quadrate is absent in Labrostochelys. This channel is present in Taphrosphys and Azabbaremys. The pterygoid flange and quadrate ramus in Labrostochelys are very close, being similar to Pelomedusidae in this feature. There is no concavity for the pterygoideus muscle attachment, but there is a low ridge on AMNH 30043 extending from the processus articularis medially on the quadrate ramus of the pterygoid that may mark an attachment site edge. The ridge is absent in AMNH 29984. The foramen palatinum posterius in Labrostochelys is formed posteriorly by the pterygoid and anteriorly by the palatine (see Palatine).</p> <p>Contacts on dorsal surface: Some of the dorsal surface of the pterygoid and crista pterygoidea are visible in both Labrostochelys skulls, but they are not well preserved and most contacts are unclear. In AMNH 30043, the crista pterygoidea meets the processus inferior parietalis of the parietal in a clear suture seen on both sides. The suture ends anteriorly in matrix, so its entire extent cannot be seen. Posterior to the foramen nervi trigemini the crista meets the prootic and posterolaterally the quadrate, although the entire extent of the latter is unclear. The processus trochlearis pterygoidei has anterior contacts with the jugal anterolaterally and with the postorbital anterodorsally. This area is preserved only on the right side of AMNH 30043 and is not well preserved.</p> <p>Structures on dorsal surface: Only part of the pterygoid dorsal surface is visible in the two Labrostochelys specimens, but some information can be obtained from the CT scans of AMNH 30043.</p> <p>The processus trochlearis pterygoidei (described above) forms the lateral margin of the sulcus palatinopterygoideus. In Labrostochelys this sulcus is not cleanly preserved, but what is preserved differs from other taxa. The sulcus is not preserved in a number of Taphrosphyini, which also makes it hard to interpret Labrostochelys. In Arenila the septum orbitotemporale and sulcus palatinopterygoideus are preserved and these are similar to the usual bothremydid condition. In Labrostochelys the postorbital-pterygoid suture is higher and the bones are much thinner. There is a lateral excavation just above the base of the processus trochlearis pterygoidei that considerably reduced the width and thickness of the septum orbitotemporale in Labrostochelys in comparison to Arenila and more generalized bothremydids like Galianemys. The medial edge of the base of the processus trochlearis pterygoidei is free rather than sutured to the postorbital or parietal. The result is a sulcus palatinopterygoideus that is much wider and more open in Labrostochelys than in Arenila and more generalized bothremydids. In Azabbaremys and Phosphatochelys there is no septum orbitotemporale and no lateral definition of the sulcus palatinopterygoideus. Taphrosphys sulcatus is not completely preserved in this area; T. ippolitoi is also unclear, but could be similar to Labrostochelys; and in T. congolensis it looks as if the septum is absent, but it is also crushed and unclear. It is possible to interpret the Labrostochelys condition as intermediate between the generalized bothremydid condition, like Arenila, and the derived condition seen in Phosphatochelys and Azabbaremys. A medially free pterygoid edge could be a common character for Labrostochelys, Azabbaremys, and Phosphatochelys.</p> <p>The crista pterygoidea in Labrostochelys can be seen in part in both skulls. Although its anterior margin, along with the processus inferior parietalis and whatever contribution the frontal and palatine may make, is not clearly defined, it is apparent that the crista in Labrostochelys, as in Taphrosphys, is much longer than the very narrow crista of Azabbaremys and Phosphatochelys. The foramen nervi trigemini in Labrostochelys has the usual elements: pterygoid ventrally, parietal anterodorsally, and prootic posterodorsally. The foramen in Labrostochelys is nearly circular, while in Phosphatochelys and Azabbaremys it is oval and more elongated.</p> <p>SUPRAOCCIPITAL (figs. 190, 193)</p> <p>Preservation: The supraoccipital is present in both Labrostochelys skulls, but all of the posterior portion is gone, as is some of the dorsal area.</p> <p>Contacts: The supraoccipital in Labrostochelys has the usual Taphrosphyini contacts: parietal dorsally, prootic anterolaterally, opisthotic posterolaterally, and exoccipital posteroventrally.</p> <p>Structures: The most prominent supraoccipital structure, the crista supraoccipitalis, is completely missing in AMNH 30043, and only the base is present in AMNH 29984. The crista is very short in other Taphrosphyini and pleurodires in general.</p> <p>EXOCCIPITAL (figs. 190, 193, 195, 277F)</p> <p>Preservation: In Labrostochelys both exoccipitals are present and complete in both skulls.</p> <p>Contacts: As in other Taphrosphyini, contacts in Labrostochelys are: supraoccipital dorsally, opisthotic laterally, quadrate ventrolaterally, and basioccipital ventrally.</p> <p>Structures: The foramen magnum in Labrostochelys is as in Taphrosphys, being slightly receded anteriorly in comparison to Phosphatochelys. The condylus occipitalis is formed entirely from the exoccipitals, and the basioccipital barely enters the neck of the condyle. The foramen nervi hypoglossi consists of a larger, more medial foramen and a smaller one in the medial wall of the foramen jugulare posterius, as in Phosphatochelys. This results in only one foramen nervi hypoglossi being visible in direct posterior view. In Taphrosphys the more lateral foramen is not placed so far into the foramen jugulare posterius. The foramen jugulare posterius is completely enclosed and widely separated from the fenestra postotica, as in other Taphrosphyini.</p> <p>BASIOCCIPITAL (figs. 190, 191, 193, 277F)</p> <p>Preservation: The basioccipital is present and complete in both skulls of Labrostochelys. Very little of its dorsal surface is visible except in the CT scans.</p> <p>Contacts: As in other Taphrosphyini the basioccipital contacts in Labrostochelys are: basisphenoid anteriorly, quadrate laterally, and exoccipitals dorsally. The basioccipital-quadrate contact is shorter than in Taphrosphys and Phosphatochelys but similar to that in Azabbaremys. The basioccipital in Labrostochelys is more triangular than in the other Taphrosphyini. The straight transverse anterior margin, narrow quadrate contacts, and straight exoccipital contacts diverging from an apex make a uniquely shaped basioccipital.</p> <p>Structures: The condylus occipitalis in Labrostochelys has no basioccipital contribution. The tuberculum basioccipitale is slightly larger in AMNH 29984 than in AMNH 30043, but both are smaller than in Taphrosphys. The tuberculum is formed by exoccipital and quadrate to a greater extent than by basioccipital. In Labrostochelys the median concavity often seen anterior to the condylus occipitalis is hardly developed. There is a shallow, irregular depression but not the clearly formed, semicircular concavity seen in Taphrosphys ippolitoi and Phosphatochelys.</p> <p>PROOTIC (fig. 193)</p> <p>Preservation: Both prootics are present in both specimens of Labrostochelys, but clear contacts are only seen in AMNH 30043.</p> <p>Contacts: The prootic contacts in Labrostochelys are common in other Taphrosphyini: parietal medially, quadrate laterally, supraoccipital posterodorsally, pterygoid ventrally, and opisthotic posteriorly. Additionally, on the left side of AMNH 30043 there is a posterolateral contact with the squamosal (see Squamosal).</p> <p>Structures: As in other Taphrosphyini, the prootic of Labrostochelys forms the dorsal portion of the foramen nervi trigemini along with the parietal and pterygoid. The prootic forms the dorsomedial part of the foramen stapedio-temporale, with the quadrate forming the ventrolateral part. As in other Taphrosphyini, the foramen nervi trigemini is very close to the foramen stapedio-temporale. The foramen stapedio-temporale in Labrostochelys opens into a shallow groove, similar to that seen in Bothremys (and probably many other Bothremydidae if well enough preserved) leading to the foramen nervi trigemini.</p> <p>OPISTHOTIC (figs. 190, 193, 195)</p> <p>Preservation: Both are preserved complete in AMNH 30043, but they lack their posterior edges in AMNH 29984.</p> <p>Contacts: Labrostochelys has the usual Taphrosphyini contacts: supraoccipital anteromedially, prootic anteriorly, squamosal posterolaterally, and exoccipital posteromedially. On the right side of AMNH 30043 the opisthotic has the usual contact with the quadrate anterolaterally. On the left side, however, the squamosal-prootic contact prevents an opisthotic-quadrate contact (see Squamosal). This latter condition is interpreted as an individual variation.</p> <p>Structures: The opisthotic forms the dorsomedial margin of the fenestra postotica, with the quadrate (see Quadrate) forming the rest. The posterolateral process of the opisthotic (fig. 287) in Labrostochelys forms part of a ventrally opening channel at the back of the skull, similar to one seen in Taphrosphys ippolitoi. This channel is absent in Phosphatochelys and Azabbaremys.</p> <p>BASISPHENOID (figs. 190, 191, 193, 277F)</p> <p>Preservation: The basisphenoid is complete in both skulls of Labrostochelys. Sutures are clearly defined in AMNH 30043, but not in AMNH 29984. The dorsal surface is not visible except in CT scans of AMNH 30043.</p> <p>Contacts: The basisphenoid of Labrostochelys has the usual Taphrosphyini contacts: pterygoids anterolaterally, quadrate laterally, and basioccipital posteriorly. The basisphenoid in Labrostochelys is unusually elongate and triangular, quite distinct from the pentagonal shape seen in Taphrosphys, the shorter, wider shapes seen in Azabbaremys and Phosphatochelys, and the V-shape seen in Arenila and Nigeremys.</p> <p>Structures: In ventral view, the basisphenoid in Labrostochelys is smooth, having no muscle attachment sites, no foramina, no nothing.</p> <p>Phosphatochelys tedfordi</p> <p>This species is based on two Eocene specimens, AMNH 30008 (holotype) and MDEt 26, which vary somewhat (table 18) and could be interpreted as separate species. We consider them as the same species and note the differences in the description. Phosphatochelys is the sister taxon to Ummulisani. The type skull was described by Gaffney and Tong (2003), and some of that description is used here.</p> <p>PREFRONTAL (figs. 196, 199, 202)</p> <p>Preservation: Both prefrontals in AMNH 30008 are present and nearly complete with clear sutures. A small amount of the ventral process seems to be broken on both sides. The left prefrontal is completely clear of matrix, but the right one has some matrix posteriorly on its ventral surface. In MDEt 26 the right prefrontal is missing, and the left one lacks its medial edge and is covered by matrix ventrally.</p> <p>Contacts: The contacts of the prefrontal in Phosphatochelys are with the maxilla anterolaterally, the frontal posteromedially, the parietal posterolaterally, and the other prefrontal anteromedially. The parietal-prefrontal contact of Phosphatochelys and Ummulisani is unusual and in fact unique among pleurodires and cryptodires (Gaffney, 1979a). It is not even approached by any other bothremydid, which generally have large prefrontals. Unlike most Pelomedusoides in which the prefrontals meet on the midline for their entire length, Phosphatochelys has a midline length much shorter than its maximum length. The suture with the frontal is strongly convex anteriorly, quite different from the straight suture in Azabbaremys and other bothremydids. The median prefrontal contact length is less than the total prefrontal length, as in chelids, Araripemys, and euraxemydids. This may be a primitive condition; however, its absence in Azabbaremys and other close relatives of Phosphatochelys makes this unlikely.</p> <p>On the ventral surface the prefrontal in Phosphatochelys contacts the parietal. The frontal is not exposed on the ventral surface. The ventral process of the prefrontal contacts the dorsal process of the maxilla, as in other Pelomedusoides. This contact area is quite narrow in Phosphatochelys, in contrast to the broad contact in Azabbaremys. The entire anterior snout area of Phosphatochelys is telescoped in comparison to Azabbaremys, Labrostochelys, and Taphrosphys.</p> <p>Structures: The prefrontal in Phosphatochelys agrees with that in Rhothonemys and Ummulisani in being a relatively large element, larger than in other Taphrosphyini and much larger than in pelomedusids and euraxemydids. The prefrontal in Phosphatochelys has a distinct, anterior projection slightly subdividing the apertura narium externa. It is larger than in Azabbaremys but smaller than in Taphrosphys and Labrostochelys.</p> <p>FRONTAL (figs. 196, 199)</p> <p>Preservation: Both frontals are present in AMNH 30008. In MDEt 26 the left frontal is present but lacks its medial margin; the right frontal is missing.</p> <p>Contacts: On the dorsal surface the frontal in Phosphatochelys contacts the prefrontal anterolaterally, the parietal posterolaterally, and the other frontal medially. The frontal is not exposed on the ventral surface, in contrast to all other bothremydids except Ummulisani.</p> <p>Structures: The frontal in Phosphatochelys is very unusual for pleurodires, except Ummulisani. It is small, widely separated from the orbital margin, and covered ventrally by a sheet of parietal that reaches the prefrontal.</p> <p>PARIETAL (figs. 196, 199, 202)</p> <p>Preservation: Both parietals in AMNH 30008 are nearly complete, but some of the ventral surface is damaged or covered by matrix. In MDEt 26, the right parietal has most of the processus inferior parietalis present but largely covered by matrix. The dorsal plate is gone except for a small posteromedial piece. The left parietal has all of the dorsal plate except posterolaterally, where it is broken off. The rest is covered by matrix.</p> <p>Contacts of dorsal plate: The dorsal plate of the parietal is large, as in Azabbaremys, but it is nearly rectangular rather than being an irregular quadrangle. It contacts the frontal anteromedially and the prefrontal anterolaterally. As mentioned (see Prefrontal), the broad prefrontal contact in Phosphatochelys and Ummulisani is unique among pleurodires and cryptodires. Also unique among pleurodires is the exposure of the parietal in the margin of the orbit. This condition is not approached by any other pleurodire or cryptodire. Laterally the parietal contacts the postorbital anteriorly and the quadratojugal posteriorly. The quadratojugal-parietal contact only occurs in Phosphatochelys, Ummulisani, and Taphrosphys among the Bothremydidae. Although it also occurs in the Euraxemydidae and Podocnemididae (including Hamadachelys), it seems to be an independent acquisition within the Taphrosphyini.</p> <p>Structures of dorsal plate: The posterior margin of the parietal along with the quadratojugal form the posterior limits of the posterior temporal emargination. The temporal emargination in Phosphatochelys is not different in extent from Azabbaremys, but the margin in Phosphatochelys is transverse while in Azabbaremys it is also straight but trends anterolaterally from the midline. To the extent it is known, this transverse edge is unique in Taphrosphyini, but a number of taxa (Rosasia, Arenila, Zolhafah) are incompletely known in the skull roof. Taphrosphys is more emarginate than Phosphatochelys. In AMNH 30008 the parietal has a very narrow exposure on the orbital margin (see Postorbital), while in MDEt 26 the postorbital-prefrontal contact prevents this.</p> <p>Contacts and structures of processus inferior parietalis: The processus inferior parietalis (fig. 202) in Phosphatochelys, exposed only on the left side of AMNH 30008, is very narrow, as in Azabbaremys, and enters the foramen nervi trigemini, also as in Azabbaremys. The processus inferior parietalis contacts the pterygoid ventrally from the foramen interorbitale anteriorly to the foramen nervi trigemini posteriorly. The parietal also sends a process ventrally on the lateral side of the sulcus palatinopterygoideus, which contacts the palatine anteriorly and the pterygoid posteriorly. This process as well as an enclosed sulcus palatinopterygoideus are absent in Azabbaremys. As in Azabbaremys, the foramen interorbitale of Phosphatochelys is relatively small compared with other Pelomedusoides. Posteriorly the parietal contacts the supraoccipital in a nearly vertical suture above the prootic contact.</p> <p>JUGAL (figs. 196, 199)</p> <p>Preservation: Both jugals are present in AMNH 30008, but neither is complete. The left one is missing only part of its posterior edge. In MDEt 26 the right jugal is missing. The left one may be lacking part of its posterior edge. Both are mostly covered by matrix on their internal surfaces.</p> <p>Contacts of lateral plate: The jugal in Phosphatochelys contacts the postorbital dorsally and the maxilla ventrally, as in other bothremydids. Because there was probably a narrow cheek emargination, the jugal may have had only a small or no contact with the quadrate (see below). The best preserved cheeks, the right sides of AMNH 30008 and MDEt 26, show no jugal-quadrate contact, but this may be due to breakage.</p> <p>Structures of lateral plate: The jugal of Phosphatochelys is widely exposed in the posteroventral margin of the fossa orbitalis, contacting the postorbital dorsally and the maxilla ventrally, all as in Azabbaremys. In both specimens of Phosphatochelys, however, there appears to be a free posterior edge along the margin of the left jugal indicating a cheek emargination. The right jugal in AMNH 30008 is damaged posteriorly in this area. On the right side the quadrate and maxilla meet. This may be due to postmortem distortion, and the rest of the skull also supports this interpretation. In MDEt 26 the left jugal has what also appears to be a free edge along its posteroventral margin, just as in the left jugal of AMNH 30008. It seems likely, then, that there was a narrow cheek emargination, as shown in the restored lateral view (fig. 196C) with part of the jugal exposed on the margin of the emargination. Nonetheless, the dorsal placement of the quadratojugal and the close approximation of quadrate and maxilla are similar to Azabbaremys and Taphrosphys.</p> <p>Contacts and structures of medial process: The medial process of the jugal is best preserved on the right side of AMNH 30008. It is barely visible in ventral view and does not extend onto the triturating surface. Most of the septum orbitotemporale is absent, as in the other Taphrosphyina, so the jugal has only a ventromedial process that reaches the maxilla and palatine in the orbital floor.</p> <p>QUADRATOJUGAL (figs. 196, 199)</p> <p>Preservation: The quadratojugal in AMNH 30008 is present only on the right side; the left one is missing. The quadratojugal is complete except along its anterior margin where some of its edge has been eroded. In MDEt 26 only the left quadratojugal is present and it has broken edges on three sides.</p> <p>Contacts: The quadratojugal in Phosphatochelys contacts the parietal medially, the postorbital anteriorly, the quadrate ventrolaterally, and the squamosal posteroventrally. The area of the postorbital contact is damaged, but the presence of the contact is not in doubt. A quadratojugal-parietal contact also occurs in the podocnemidids, Erymnochelys and Peltocephalus, but among bothremydids it is known only in Taphrosphys, Ummulisani, and Labrostochelys. In Taphrosphys the quadratojugal is more extensive ventrally, and a jugal-quadrate contact is present.</p> <p>Structures: In most turtles the quadratojugal is a large C-shaped element lying along the anterior margin of the quadrate on the cheek. This is the case in bothremydids like Foxemys, but in the Taphrosphyini (unknown in Nigeremys and Arenila) the quadratojugal lies well above the main body of the quadrate and there is a jugal-quadrate contact.</p> <p>SQUAMOSAL (figs. 196, 199, 203, 286C)</p> <p>Preservation: Both squamosals are present in AMNH 30008; the right one is complete and the left one lacks some of its anterior process. In MDEt 26, parts of both squamosals are present, the left one is nearly complete, but the right one is lacking most of its lateral area.</p> <p>Contacts: The squamosal in AMNH 30008 is the usual cone-shaped element lying on the posterolateral corner of the quadrate. It contacts the opisthotic medially on the dorsal, medial, and ventral surfaces. A short process of the squamosal contacts the quadratojugal along the lateral edge of the temporal embayment, as in Azabbaremys.</p> <p>Structures: The squamosal in Phosphatochelys has a ventral flange or deep ridge, oriented vertically anteroposteriorly (fig. 203, sqf). This also occurs in Taphrosphys, Labrostochelys, Ummulisani, and Rhothonemys. On its lateral surface, there is a small ridge or tubercle overlapping outside the sulcus eustachii (fig. 286C) that also occurs in Taphrosphys and Labrostochelys and in some Bothremys maghrebiana.</p> <p>POSTORBITAL (figs. 196, 199)</p> <p>Preservation: The postorbital in Phosphatochelys is present on both sides of AMNH 30008. The left one is nearly complete; only some of its posterior edge is damaged, but the right postorbital is damaged with its posterior margin missing. The internal surface is visible on the left side, but only partially on the right. In MDEt 26 the postorbital is present on the left side only, in a more posterior, disarticulated fragment that is not definitely in its original position, and in the orbital margin. No medial process is visible.</p> <p>Contacts of lateral plate: The postorbital of Phosphatochelys is a roughly square element, contacting the parietal medially, the quadratojugal posteriorly, the quadrate posteroventrally, and the jugal anteroventrally. The absence of a frontal contact, due to the prefrontal-parietal contact, is unusual and only occurs elsewhere in Ummulisani. The short postorbital of Phosphatochelys is completely separated from the posterior temporal emargination by the parietal-quadratojugal contact, quite different from the long postorbital of Azabbaremys that reaches the temporal emargination. It is possible that a very narrow postorbital-prefrontal contact was present, but as preserved the right side is eroded and the left side is broken at this point. Thus, we have restored the postorbital with no prefrontal contact and a narrow orbital exposure of the parietal. We consider this to be equivocal, however. In MDEt 26, only the left side preserves the postorbital, and here a very small postorbital-prefrontal contact is present, preventing orbital exposure of the parietal.</p> <p>Contacts of medial process: As in most other Taphrosphyini, Phosphatochelys has no jugal-postorbital or palatine-postorbital contact of the medial process. The postorbitalparietal contact is small and there is no pterygoid contact here as well.</p> <p>Structures of medial process: In most bothremydids the postorbital has a medial process that contacts the jugal and palatine to form the septum orbitotemporale. In the subtribe Taphrosphyina, however, this wall is small or absent. In Phosphatochelys the medial surface of the postorbital has a vertical ridge continuous with one from the jugal, which represents the fossa orbitalis margin. A much lower ridge is present in Azabbaremys. The postorbital contribution to the floor of the fossa orbitalis is also absent.</p> <p>PREMAXILLA (figs. 196, 197, 199)</p> <p>Preservation: Both premaxillae are present in AMNH 30008, but the right one lacks the labial ridge. In MDEt 26 both premaxillae are also present and nearly complete.</p> <p>Contacts: The premaxilla in Phosphatochelys contacts the maxilla laterally and the other premaxilla medially. The vomer is missing in both skulls.</p> <p>Structures on dorsal surface: The premaxilla in Phosphatochelys forms a deep, acute labial ridge with a median notch, in contrast to the hook seen in Azabbaremys. In Azabbaremys and many Pelomedusoides the ventral rim of the apertura narium externa protrudes well anterior to the labial ridge. In Phosphatochelys, however, the lower rim of the apertura is distinctly recessed, unlike any other bothremydid, so that the labial ridge is the anteriormost part of the skull. In Azabbaremys there is a median ridge with low troughs on either side communicating with the apertura narium externa. In Phosphatochelys there is also a median ridge but it is acute, not blunt as in Azabbaremys, and there are no troughs. Phosphatochelys does have a low concavity on the premaxilla that produces the recessed shape of the lower rim of the apertura. Below the concavity on the anterior face in Phosphatochelys there is a distinct pattern of the nutrient foramina, presumably for the horny beak. These occur in a band along the ventral edge of the labial ridge, premaxilla and maxilla, and which is slightly raised above the more dorsal parts of these bones. In Azabbaremys, Taphrosphys, and other bothremydids, the nutrient foramina are not so prominent on the outer surface of premaxilla and maxilla. The horizontal plate of the premaxilla forms the floor of the fossa nasalis, and in Phosphatochelys these form an acute dorsal ridge on the midline that is absent in Azabbaremys.</p> <p>The premaxilla in AMNH 30008 is shorter than the premaxilla in MDEt 26, and it is not as inclined. The median notch is slightly deeper in AMNH 30008 than in MDEt 26. In both specimens there is a distinct sulcus or groove along the ventral edge of the apertura narium externa (fig. 279A). This sulcus is parallel-sided and seems to be a continuation of a sulcus running along the ventrolateral corner of the fossa nasalis (see Maxilla).</p> <p>Structures on ventral surface: On the ventral surface, the premaxilla in Phosphatochelys forms the anterior part of the very high and acute labial ridge, higher than in Azabbaremys or any other bothremydid. Also in contrast to Azabbaremys and other bothremydids, the horizontal part of the triturating surface in Phosphatochelys is very narrow, particularly on the premaxilla, although it is more horizontal in MDEt 26 than in AMNH 30008. The lingual ridge might be identified as the very low, rounded margin separating the triturating surface proper from the median concavity that leads into the apertura narium interna. This concavity is large in Phosphatochelys, being wider and more open posteriorly in comparison to Azabbaremys.</p> <p>MAXILLA (figs. 196, 197, 199)</p> <p>Preservation: Both maxillae are present in AMNH 30008 and both are slightly damaged. The left maxilla is nearly complete but has a horizontal break running through the main body; not much bone seems to be missing however. The right maxilla is missing its anteriormost edge and has a broken area below the orbit. Both have the internal portion preserved. In MDEt 26, both maxillae are preserved; the left one is nearly complete. The right one is missing a small part of its dorsal margin.</p> <p>Contacts of vertical plate: The maxilla of Phosphatochelys contacts the premaxilla anteromedially, the prefrontal anterodorsally in an unusually narrow suture, and the jugal posterodorsally.</p> <p>Structures of vertical plate: The vertical plate in Phosphatochelys is more curved, convex anterolaterally, than the very flat maxilla of Azabbaremys, and it has a relatively larger fossa orbitalis and apertura narium externa than in Azabbaremys. As preserved, the maxilla contacts the quadrate on the right side. Based on the apparent free edges of the maxilla and jugal on the left side and some distortion on the right side, we have restored Phosphatochelys with a narrow cheek emargination. The prefrontal-maxilla contact is best preserved on the left side. It is much narrower than in Azabbaremys.</p> <p>Contacts of horizontal plate: In ventral view, the maxilla contacts the premaxilla anteromedially, the jugal posteriorly, and the palatine posteromedially. In AMNH 3008 the area around the premaxilla-maxilla suture is broken on both sides as the suture approaches the apertura narium interna. The vomer, presumably present, is missing in both specimens. It is possible that the maxilla contacted the vomer, and, if not, it probably came close. The jugal does not extend onto the triturating surface in Phosphatochelys. The palatine contact is also farther from the triturating surface than it is in Azabbaremys. In the floor of the fossa orbitalis the horizontal plate of the maxilla contacts the palatine posteromedially and the jugal posterolaterally.</p> <p>Structures of horizontal plate: The medial parts of the maxilla form part of the fossa nasalis anteriorly and the fossa orbitalis posteriorly. The fossa nasalis is relatively large for a bothremydid and does not have the posterolateral pocket seen in Azabbaremys. Along the ventrolateral margin of the fossa nasalis is a deep groove beginning as a shallow groove or sulcus (see Premaxilla) on the premaxilla and running posterolaterally to the fossa orbitalis (fig. 279A). This groove has two large foramina in it that open ventrolaterally into the main body of the maxilla. In Podocnemis and Pelusios, Albrecht (1976) described the canalis infraorbitalis and canalis alveolaris superior system that connect a series of foramina and contain the supramaxillary and superior alveolar arteries. The groove and foramina in Phosphatochelys seem to be part of this system. Although we have not seen it developed to this extent in any other Pelomedusoides, other taxa do have foramina in the same place in the fossa nasalis that communicate with the alveolar canals.</p> <p>The lower border of the orbital margin is relatively high above the floor of the fossa nasalis, resulting in a deep pocket, deeper than seen in Azabbaremys and much deeper than seen in Bothremys, Foxemys, Podocnemis, and pelomedusids, but similar in extent to the one in Rhothonemys.</p> <p>The ventral portion of the maxilla bears the triturating surface and forms part of the palate. The labial ridge of Phosphatochelys is much deeper than in Azabbaremys or other bothremydids. The snout is unusually foreshortened, and the labial ridge is very deep, resulting in a deep, horseshoe-shaped space. The flat portion of the triturating surface width is very small and not distinctly separated from the labial ridge or the lingual edge. The lingual ridge barely exists: it is just the rounded margin for the apertura narium interna. The triturating surface has the usual nutrient foramina but it is smooth, not corrugated as in Azabbaremys.</p> <p>VOMER</p> <p>Preservation: There is no vomer present in either specimen, but that may be due to postmortem loss.</p> <p>PALATINE (figs. 196, 197, 199)</p> <p>Preservation: Both palatines in AMNH 30008 are present but both are missing some of the anterior margin, although the right one seems to be nearly complete. Most of the dorsal surfaces are visible except posteromedially. In MDEt 26, both palatines are complete but visible only in ventral view.</p> <p>Contacts: The palatine in Phosphatochelys contacts the maxilla anterolaterally, the pterygoid posteriorly, and the other palatine medially. In the orbital floor the palatine has a broad anterolateral contact with the maxilla and a broad lateral contact with the jugal. The absence of a septum orbitotemporale is associated with the absence of a postorbital contact.</p> <p>Structures on dorsal surface: The dorsal surface of the palatine is complex, as it is involved in the fossa orbitalis, the sulcus palatinopterygoideus, and the remnant of the septum orbitotemporale. In Phosphatochelys, as in Azabbaremys and Taphrosphys, the septum orbitotemporale, so prominent in other bothremydids, is mostly absent. In dorsal view the palatine of Phosphatochelys is similar to Azabbaremys in forming most of the floor of the orbit and in having a broad anterolateral maxilla contact and a broad lateral jugal contact. The surface of the orbital floor is deeply concave, even more than in Azabbaremys. In contrast to Azabbaremys, Phosphatochelys has a narrow but completely enclosed sulcus palatinopterygoideus (figs. 202, 279A). In Azabbaremys the lateral wall of the sulcus is gone; in Phosphatochelys it is narrow but complete.</p> <p>Structures on ventral surface: In ventral view the palatine in Phosphatochelys is smaller than the unusually large palatine of Azabbaremys. The palatine-pterygoid suture is roughly transverse in Phosphatochelys, not concave anteriorly as in Azabbaremys. The edges of the apertura narium interna in Phosphatochelys are best preserved in MDEt 26. They are more circular rather than triangular as in Azabbaremys. As in Azabbaremys, only a small part of the palatine enters onto the triturating surface. The palatine forms the roof of the choanal opening into the mouth, the apertura narium interna. In Phosphatochelys, Azabbaremys, and Nigeremys this roof is highly arched dorsally, in contrast to the flatter surface of other bothremydids. The foramen palatinum posterius in Phosphatochelys is formed almost entirely by the palatine, but it is very close to the pterygoid suture, and a small spur of the pterygoid may enter the foramen. The foramen palatinum posterius of Phosphatochelys is in a comparable position to that seen in Azabbaremys, but it is much more medial and closer to the apertura narium interna in Phosphatochelys than in Azabbaremys or other bothremydids.</p> <p>QUADRATE (figs. 196, 197, 199, 202, 203, 286C)</p> <p>Preservation: Both quadrates in AMNH 30008 are present and nearly complete. The left one lacks its anterior edge and the right one has some breakage along the jugal-maxilla contact. In MDEt 26, both quadrates are present. The left one seems to be all there, but it is cracked in a number of places with some displacement of the pieces. The right quadrate is less deformed, but it is missing its dorsal margin.</p> <p>Contacts on lateral surface: In lateral view the quadrate of Phosphatochelys contacts the jugal anteriorly, the postorbital anterodorsally, the quadratojugal dorsally, and the squamosal posterodorsally. As preserved, there is a maxilla contact anteroventrally on the right of AMNH 30008, but this is interpreted as a narrow cheek emargination (see Maxilla). Both quadrates in MDEt 26 preserve an anterior margin that looks like a free edge, not a sutural contact.</p> <p>Structures on lateral surface: The cavum tympani in Phosphatochelys (fig. 286C) has a completely enclosed incisura columellae auris, as in Azabbaremys and most bothremydids. Also as in Azabbaremys, the cavum is hemispherical and lacks a fossa precolumellaris. However, Phosphatochelys has a well-developed antrum postoticum, larger than in Taphrosphys sulcatus, which is in strong contrast to Azabbaremys, which completely lacks an antrum postoticum. At the posterior margin of the cavum tympani in Phosphatochelys is a groove for the eustachian tube, as in Azabbaremys. In Azabbaremys this groove is open, but in Phosphatochelys there is a well-developed ventral process or overhang that partially encloses the eustachian tube. As in Azabbaremys, there is a shelf along the ventral margin of the cavum tympani. It is very similar in size and shape in both Phosphatochelys and Azabbaremys.</p> <p>Contacts on dorsal and anterior surfaces: The quadrate in Phosphatochelys contacts the prootic medially, the opisthotic posteromedially, and the squamosal posterolaterally. As in Azabbaremys and Taphrosphys, there is no quadrate-supraoccipital contact that is seen in other bothremydids. The dorsally directed trough and associated ridge (see Pterygoid) formed by pterygoid and quadrate lie just anterior to these foramina.</p> <p>Structures on dorsal and anterior surfaces: The quadrate forms the posteroventral margins of the foramen stapedio-temporale and the foramen nervi trigemini, as in other bothremydids. These formaina are verly close to each other in Phosphatochelys.</p> <p>Contacts on ventral surface: In ventral view the quadrate of Phosphatochelys contacts the pterygoid anteromedially, the basisphenoid medially, and the basioccipital posteromedially, as in Azabbaremys and other bothremydids. As in Azabbaremys, there is a narrow contact with the basisphenoid between the broader basioccipital and pterygoid contacts. The quadrate contacts the quadrate ramus of the pterygoid in a suture extending from the basisphenoid along the processus articularis of the quadrate, as in Azabbaremys and other pleurodires.</p> <p>Structures on ventral surface: The foramen posterius canalis carotici interni is formed in the pterygoid-quadrate suture, but more is formed by the quadrate than by the pterygoid. In contrast to Azabbaremys, there is no contribution from the basisphenoid. There is a distinct groove on the quadrate leading anteriorly into the foramen posterius canalis carotici interni.</p> <p>The processus articularis of the quadrate in Phosphatochelys is longer than in Azabbaremys so that the condylus mandibularis is much farther from the plane of the palate in Phosphatochelys than it is in Azabbaremys. This is presumably related to the very deep labial ridge in Phosphatochelys, although a lower jaw will be needed to demonstrate this. The quadrate and the basioccipital form the tuberculum basioccipitale, which is higher and more prominent than in Azabbaremys.</p> <p>Contacts on posterior surface: In posterior view the quadrate in Phosphatochelys contacts the squamosal dorsolaterally, the opisthotic dorsally, the exoccipital medially, and the basioccipital ventromedially (not quite visible in occipital view).</p> <p>Structures on posterior surface: The quadrate and opisthotic combine to form a fully enclosed fenestra postotica (fig. 203) in Phosphatochelys, very similar to that in Azabbaremys. In the shelf leading into the fenestra, both dorsally and ventrally, are low spurs suggesting a division of stapedial artery and lateral head vein. However, distinct ridges as seen in Taphrosphys are absent. As in Azabbaremys, the fenestra postotica of Phosphatochelys is widely separated from the foramen jugulare posterius by a well-developed opisthotic-quadrate contact. In Phosphatochelys and Azabbaremys the quadrate contacts the exoccipital and basioccipital ventral to the foramen jugulare posterius. On the posterior surface of Phosphatochelys is a continuation of the sulcus eustachii from the cavum tympani. This groove is roughly horizontal and is well defined dorsally by a shelf that has a slight ventral ridge resulting in an overhang partially enclosing the groove. Medially the groove flattens out and disappears.</p> <p>PTERYGOID (figs. 196, 197, 199, 202)</p> <p>Preservation: Both pterygoids in AMNH 30008 are present and nearly complete. The processus trochlearis pterygoidei is displaced on the right side but intact on the left. Both pterygoids are present and nearly complete in MDEt 26 as well. Only the ventral surfaces are visible due to matrix. On both sides the thin flange below and behind the processus trochlearis pterygoidei is divided into two narrow flanges. However, close examination reveals this to be an artifact of overpreparation; the flange was originally one piece, as in other pleurodires.</p> <p>Contacts on ventral surface: In ventral view the pterygoid contacts in Phosphatochelys are as in other bothremydids: palatine anteriorly, quadrate posterolaterally, basisphenoid posteromedially, the other pterygoid medially. The midline pterygoid contact is slightly longer than in Azabbaremys.</p> <p>Structures on ventral surface: The foramen posterius canalis carotici interni (see Quadrate) lies in the pterygoid-quadrate suture midway between the basisphenoid and lateral edge of the quadrate. Nonetheless, the foramen is in a similar position in Azabbaremys despite the fact that the basisphenoid enters the foramen in Azabbaremys. The basisphenoid is much wider in Azabbaremys than in Phosphatochelys, and that may be a factor.</p> <p>The pterygoideus muscle scar is weakly developed in Azabbaremys, but it is absent in Phosphatochelys. There is no indication at all of its presence. However, there is a dorsally directed trough formed by pterygoid and quadrate in Phosphatochelys that may have held an insertion for the M. pterygoideus (fig. 203, in the area labeled ‘‘pt’’). This trough has a sharp ridge on the quadrate as its lateral margin and the crista pterygoidea and processus inferior parietalis as its medial limits. It trends posteroventrally from the parietal down to the condylus mandibularis and is open anteriorly. As it reaches the ventral edge of the pterygoid its posterior wall ends, and only the lateral ridge reaches the condylus mandibularis. Thus, in ventral view (fig. 197), the end of the trough lies behind the processus trochlearis pterygoidei just lateral to the thin web of bone behind the processus. This structure, developed to the extent seen in Phosphatochelys, and also in Ummulisani, is unique among pleurodires. It is possible that this trough contains a division of the M. pterygoideus (Schumacher, 1973), probably either the pars ventrolateralis or possibly the pars ventroposterior (seen in Podocnemis).</p> <p>The processus trochlearis pterygoidei of Phosphatochelys is relatively well preserved on both sides. In many pleurodire fossils it is damaged due to the thin bone. In Azabbaremys only part of one is preserved, but it is similar to that in Phosphatochelys. The processus in both genera extends posteriorly at an angle of roughly 30 ° from the midline. There is a low ridge along the ventrolateral margin of the processus in Phosphatochelys, also as in Azabbaremys but absent in pelomedusids. The base of the processus trochlearis pterygoidei contacts the parietal anterodorsally and the palatine anteroventrally. The foramen palatinum posterius (see Palatine) is formed almost entirely by the palatine with a very narrow contribution from the pterygoid.</p> <p>Contacts on dorsal surface: The pterygoid at the base of the processus trochlearis pterygoidei contacts the parietal anterodorsally and the palatine anterolaterally. The crista pterygoidea is very short in Phosphatochelys; the pterygoid contacts the parietal dorsally and the prootic behind the foramen nervi trigemini.</p> <p>Structures on dorsal surface: The crista pterygoidea in Phosphatochelys is completely covered with matrix on the right side and only partially exposed on the left in AMNH 30008. However, the left side does show the anterior margin and the foramen nervi trigemini clearly. The crista pterygoidea in Phosphatochelys is narrow in comparison to Bothremydini, but it is not as narrow as in Azabbaremys. In Azabbaremys both the processus inferior parietalis and the crista pterygoidea are roughly half the width of these walls in Phosphatochelys. The posterior edge of the crista pterygoidea forms the anteroventral margin of the foramen nervi trigemini in Phosphatochelys, as in Azabbaremys. In Phosphatochelys in contrast to Azabbaremys, there is a high, thin ridge along the anterior margin of the foramen nervi trigemini separating it from the more anterior part of the crista pterygoidea.</p> <p>SUPRAOCCIPITAL (figs. 196, 199, 203)</p> <p>Preservation: The supraoccipital in AMNH 30008 is nearly complete and well preserved, with all sides in it being visible. In MDEt 26 the supraoccipital is missing most of the crista supraoccipitalis, but it is otherwise complete.</p> <p>Contacts: The laterally projecting otic portion of the supraoccipital in Phosphatochelys contacts the prootic anterolaterally, the opisthotic laterally, and the exoccipital posterolaterally. It does not contact the quadrate, although in MDEt 26 the opisthotic-prootic contact is much narrower than in AMNH 30008.</p> <p>Structures: The supraoccipital of Phosphatochelys underlies the two parietals on the midline but not to the extent seen in Azabbaremys. This is presumably related to the shorter parietals in Phosphatochelys, because the supraoccipitals in both Phosphatochelys and Azabbaremys are quite similar. The crista supraoccipitalis is complete in Phosphatochelys and short as in Azabbaremys, extending only slightly past the level of the condylus occipitalis. Phosphatochelys has a slightly shorter crista than in Azabbaremys. The blade of the crista is deeper in Azabbaremys than in Phosphatochelys, but this seems to be related to the larger foramen magnum of Phosphatochelys, being in turn presumably related to its smaller size.</p> <p>EXOCCIPITAL (figs. 196, 199, 203)</p> <p>Preservation: Both exoccipitals are preserved in AMNH 30008 and in MDEt 26; they are complete, free of matrix, and have clear sutures.</p> <p>Contacts: The exoccipital in Phosphatochelys contacts the supraoccipital dorsally, the opisthotic laterally, the quadrate ventrolaterally, and the basioccipital ventrally, as in Azabbaremys and other bothremydids.</p> <p>Structures: The exoccipital in Phosphatochelys forms all of the condylus mandibularis, and the basioccipital enters the neck of the condyle and almost reaches the articulation surface, in contrast to the condyle in Azabbaremys where the basioccipital is more anterior. The exoccipitals are slightly eroded on the midline or perhaps they were not fully ossified, giving the occipital condyle a bilobed appearance as in BMNH R 16370, the type specimen of Azabbaremys moragjonesi. The foramen jugulare posterius is formed mostly by the exoccipital, with between a third and a half being formed by the opisthotic, in contrast to Azabbaremys in which only a very narrow process of the opisthotic enters the foramen margin. The foramen jugulare posterius is entirely enclosed by bone, as in Taphrosphys, Arenila, and Bothremys but in contrast to the open condition of Foxemys and Polysternon.</p> <p>Between the foramen jugulare posterius and the condylus occipitalis are the two foramina nervi hypoglossi entirely formed by the exoccipital. Their positions differ significantly in Phosphatochelys and Azabbaremys. In Phosphatochelys the more medial foramen lies on the roughly flat posterior surface of the exoccipital and opens posterolaterally and is clearly visible in posterior view. The more lateral foramen lies within the entry to the foramen jugulare posterius and is so far within the margin that it is completely concealed in posterior view on the right side and only barely visible on the left. The more medial foramen nervi hypoglossi in Phosphatochelys is larger in diameter than the more lateral one. In Azabbaremys both foramina are very close to one another, they are the same size, and neither is close to the foramen jugulare posterius.</p> <p>BASIOCCIPITAL (figs. 196, 197, 199, 203)</p> <p>Preservation: The basioccipitals in AMNH 30008 and MDEt 26 are complete and clearly defined.</p> <p>Contacts: The basioccipital in Phosphatochelys contacts the basisphenoid anteriorly, the quadrates laterally, and the exoccipitals posteriorly, as in Azabbaremys. Phosphatochelys has a broadly curved anterior margin rather than the straight suture seen in Azabbaremys. The basisphenoid contact is smaller and the quadrate contact more extensive in Phosphatochelys.</p> <p>Structures: The basioccipital in Phosphatochelys makes up the medial half of the very low tuberculum basioccipitale. Between the paired tubercula is a median concavity that is deeper and more clearly defined than in Azabbaremys. The concavity in Phosphatochelys is almost exactly coincident with the basioccipital.</p> <p>PROOTIC (figs. 196, 199, 202)</p> <p>Preservation: Both prootics are present and complete in both skulls. In AMNH 30008 the left one is free of matrix, but the right one is covered anteromedially. Both have clear sutures. In MDEt 26 the prootics appear complete but are covered by matrix anteriorly.</p> <p>Contacts: The prootic in Phosphatochelys contacts the supraoccipital posteromedially, the parietal medially, the pterygoid ventrally (internal to the foramen nervi trigemini), the quadrate laterally, and the opisthotic posterolaterally. The opisthotic contact is broader in AMNH 30008 and narrower in MDEt 26.</p> <p>Structures: The prootic forms the dorsomedial margin of the foramen nervi trigemini, the parietal forms its anterodorsal margin, the pterygoid forms its anteroventral margin, and the quadrate forms its posteroventral margin. The foramen nervi trigemini is visible and complete on the left side of AMNH 30008 as well as the foramen stapedio-temporale, which lies entirely on the anterior face of the otic chamber and is not visible in dorsal view. This is the same condition in nearly all bothremydids. The quadrate forms the lower half of the foramen stapedio-temporale (see Quadrate). Both foramina are very close to each other.</p> <p>OPISTHOTIC (figs. 196, 197, 199, 203)</p> <p>Preservation: Both opisthotics are complete and well preserved with clear sutures in MDEt 26 and AMNH 30008.</p> <p>Contacts: The opisthotic in Phosphatochelys has the usual bothremydid contacts: supraoccipital dorsomedially, prootic anteromedially, quadrate anterolaterally, squamosal posterolaterally, quadrate (again) ventrolaterally, and exoccipital posteromedially.</p> <p>Structures: The opisthotic forms the roof of the fenestra postotica, with the ventral and greater portion being formed by the quadrate. The fenestra in Phosphatochelys is oblong with small ridges distally presumably indicating the positions of the stapedial artery and lateral head vein (see Quadrate). The processus interfenestralis of the opisthotic forms the wall between the fenestra postotica and foramen jugulare posterius, contacting the quadrate ventrally. This wall is quite thick in Phosphatochelys as it is in Azabbaremys and most Taphrosphyini and Bothremydini.</p> <p>BASISPHENOID (figs. 196, 197, 199)</p> <p>Preservation: The basisphenoid is complete and clearly defined in MDEt 26 and AMNH 30008, but its dorsal surface is covered with matrix.</p> <p>Contacts: The basisphenoid of Phosphatochelys is roughly triangular in ventral view. It has a straight posterior contact with the basioccipital, posterolateral contacts with the quadrates, and anterolateral contacts with the pterygoids.</p> <p>Structures: The basisphenoid in Phosphatochelys is about as wide as long, in contrast to the very short and wide basisphenoid in Azabbaremys.</p> <p>Ummulisani rutgersensis</p> <p>At present, three skulls of this taxon are known, but because two of them were discovered very late in the development of this project, it was only possible to describe in detail and figure one without incurring significant delays. The other two will be described soon (Gaffney and Tong, in prep.). Unfortunately, the figured skull, AMNH 30563, is the least complete of the three; although not ideal, it is complete enough to serve as the type. One of the new skulls, AMNH 30562, is associated with a plastron that we were able to describe and figure (figs. 268, 269), even though the skull is still being prepared. The third skull, AMNH 30569, is nearly complete. Some information from all three skulls is included in the description below.</p> <p>Ummulisani is the sister taxon to Phosphatochelys within the subtribe Taphrosphyina.</p> <p>PREFRONTAL (figs. 204, 207)</p> <p>Preservation: Both prefrontals are complete in AMNH 30563 except for a small part of the maxilla contact. The posteromedial edge of the ventral process could have had a palatine contact; if so, this is also missing.</p> <p>Contacts: There is a long medial contact with the other prefrontal and a very narrow anterolateral contact with the maxilla. The maxilla contact in Ummulisani is about the same size and position as in Phosphatochelys. It is narrower than in Taphrosphys and Azabbaremys. The posterior contact in the type specimen of Ummulisani is a straight transverse suture with the parietal. In the two other specimens of Ummulisani, the small frontals lie in the medial part of this suture. The only other pleurodire or turtle to have a prefrontal-parietal contact is Phosphatochelys. Phosphatochelys also has small frontals that are separated from the orbital margin by the prefrontal-parietal contact. Many other turtles have small frontals, but none combine that with large prefrontals to produce a prefrontal-parietal contact.</p> <p>Structures: The prefrontal in Ummulisani has the midline projection seen in other Taphrosphyini. It is about the same size and shape as in Phosphatochelys.</p> <p>Ummulisani is unique in having a hornlike process on the anterolateral margin of each prefrontal, developed to about the same extent in all three skulls. This process is cone-shaped and lies at the anterodorsal margin of the orbit. There is nothing similar in any other turtle. Phosphatochelys and other Taphrosphyini do not even have swellings or thickened bone in this area. Clearly, these horns were part of the complex rutting rituals in which males bashed what few brains they had out of each other, resulting in their extinction.</p> <p>The ventral surface is visible in AMNH 30563. The prefrontal forms almost all of the roof of the fossa nasalis and the major part of the sulcus olfactorius.</p> <p>FRONTAL</p> <p>The frontal is absent in AMNH 30563, but a small frontal is present in the two other Ummulisani specimens, not yet described (Gaffney and Tong, in prep.). The absence of the frontal is presumably individual variation, not of particular systematic significance.</p> <p>PARIETAL (figs. 204, 207)</p> <p>Preservation: Both parietals are present in AMNH 30563. The dorsal plate of the right one is complete except on its posterior edge. The left one has a broken lateral and posterior margin. The processus inferior parietalis of both is present but slightly damaged by dorsoventral crushing that has obscured its ventral contacts. The anterior margin of the processus is broken on both sides.</p> <p>Contacts of dorsal plate: The large parietal of Ummulisani contacts the other parietal medially, the prefrontal anteriorly (see Prefrontal), the postorbital anterolaterally, the quadratojugal posterolaterally, and a small dorsal plate of the supraoccipital posteromedially. Except for the absence of a frontal contact in the type specimen, AMNH 30563, these are similar to ones found in Phosphatochelys.</p> <p>Structures of dorsal plate: The posterior temporal emargination in AMNH 30563 is represented by a broken edge on both sides, but, as preserved, the skull roof is nearly as extensive as in Phosphatochelys. The two new skulls show a similarly extensive skull roof. On the ventral surface, Ummulisani lacks the septum orbitotemporale and has a transverse ridge instead, marking the posterior limits of the fossa orbitalis. This shows that the fossa orbitalis was expanded, as in Phosphatochelys.</p> <p>Contacts of processus inferior parietalis: The anterior margin of the processus inferior parietalis is mostly a broken edge; only a small part is present on the right side, and the palatines are missing as well. The possible palatine contact, as in Phosphatochelys, cannot be determined. The pterygoid contact is much wider in Ummulisani than in Phosphatochelys. The prootic contact above the foramen nervi trigemini is unclear posteriorly.</p> <p>Structures of processus inferior parietalis: The foramen interorbitale is too poorly preserved in AMNH 30563 to characterize, but it is possible to say that the remaining portion of the processus inferior parietalis is much wider than in Phosphatochelys. In</p> <p>Phosphatochelys the parietal has a ventral process that meets the pterygoid lateral to the sulcus palatinopterygoideus. In Ummulisani, the pterygoid area defining the sulcus is gone, but a small parietal process is present, although it does not seem to have been long enough to reach the pterygoid when the pterygoid was there.</p> <p>JUGAL (figs. 204, 207)</p> <p>Preservation: Only part of the right jugal is probably present in AMNH 30563, and that seems to have been displaced during an earlier bout of preparation. A bone below the orbit has a broken medial process that seems to be identifiable as a jugal, but it overlaps part of the quadrate behind it. The orbital margin and possible sutures, however, suggest that the bone may be the jugal and may only be displaced from its original position. The absence of a medial process and clear sutures preclude any further description.</p> <p>QUADRATOJUGAL (figs. 204, 207)</p> <p>Preservation: At least the anterior part of the right quadratojugal is present.</p> <p>Contacts: The quadratojugal in Ummulisani contacts the parietal medially, the postorbital anteriorly, and the quadrate ventrolaterally.</p> <p>Structures: The quadratojugal in Ummulisani is a small element placed well dorsal to the cheek margin. It is rectangular and not Cshaped. In these features it agrees with the quadratojugal in Phosphatochelys and Azabbaremys.</p> <p>SQUAMOSAL (figs. 204, 207)</p> <p>Preservation: The vicissitudes of death have dealt harshly with the squamosals of AMNH 30563. Only a few fragments of the right one remain, and the left one is badly broken and hanging on only by my imagination.</p> <p>Contacts: The only contact remaining is with the quadrate, somewhat anteromedially.</p> <p>Structures: The antrum postoticum is absent in Ummulisani, and the squamosal has no sign of a remnant canal or space. The left squamosal in Ummulisani has enough preserved to show that the ventral flange is large and similar to that structure in Taphrosphys, Rhothonemys, Phosphatochelys, and Labrostochelys. The lateral tubercle area is not preserved well enough to determine in AMNH 30563.</p> <p>POSTORBITAL (figs. 204, 207)</p> <p>Preservation: Only the right postorbital is present in AMNH 30563.</p> <p>Contacts of lateral plate: The postorbital in Ummulisani contacts the parietal dorsomedially, the quadrate posteroventrally, the quadratojugal posteriorly, and the jugal ventrally. The jugal contact, however, is unclear, as the jugal is not definitely identified. The contacts are as in Phosphatochelys.</p> <p>Structures of lateral plate: The postorbital in Ummulisani forms the posterior margin of the orbit and does not enter the temporal margin due to its relatively small size, in comparison to a form like Azabbaremys.</p> <p>Contacts of medial process: The medial process only contacts the parietal medially in Ummulisani, as the septum orbitotemporale is nearly absent.</p> <p>Structures of medial process: As in Phosphatochelys, the fossa orbitalis in Ummulisani is open posteriorly and the septum orbitotemporale is nearly absent. The postorbital and parietal form a transverse ridge on the ventral surface of the skull roof. This ridge is the remnant of the septum orbitotemporale and forms the posterior margin of the fossa orbitalis. The sulcus palatinopterygoideus is not preserved in AMNH 30563, so its degree of formation is not determinable.</p> <p>PREMAXILLA (figs. 204–207)</p> <p>Preservation: Both premaxillae are present and nearly complete in AMNH 30563, but their contacts with the maxillae are broken and filled with glue.</p> <p>Contacts: The premaxilla in Ummulisani contacts the other premaxilla medially and the maxilla posterolaterally. The vomer and the vomer contact are not preserved.</p> <p>Structures on dorsal surface: The premaxilla forms the floor of the fossa nasalis, which in Ummulisani is relatively large. The apertura narium externa is separated from the anterior skull surface only by a low ridge and a slight change in slope in Ummulisani, rather than by a sharp change in slope, as in Phosphatochelys and other Taphrosphyini. There is a midline ridge or carina that runs from the anterior margin of the premaxilla, the labial ridge, posteriorly through the apertura narium externa and into the fossa nasalis. In Phosphatochelys, the ridge is only within the fossa nasalis. In Ummulisani, the premaxilla is protuberant on the midline, forming an acute point, rather than the curved snout margin seen in Phosphatochelys, Taphrosphys, and Nigeremys. Rhothonemys has a slight protuberance, but not to the extent seen in Ummulisani. Labrostochelys has an extensive premaxillary process, but it ends in a blunt edge different from that in Ummulisani.</p> <p>The floor of the fossa nasalis is a broad, curved trough separated by the midline carina. There is a groove along the inner margin of the apertura narium externa, like that seen in Phosphatochelys. The midline carina has a dorsal process where it intersects the apertura narium externa.</p> <p>Structures on ventral surface: The labial ridge is inclined in Ummulisani, different from the vertical ridge in Phosphatochelys. The edge of the ridge is sharp and the bone is much thinner than in Phosphatochelys, and the more horizontal triturating surface produces a wider, flat area behind the labial ridge. The midline embayment in Ummulisani is wide as in Phosphatochelys, but it is much shallower. As on the dorsal surface, the labial ridge forms a pointed anterior protuberance in Ummulisani not seen in Phosphatochelys.</p> <p>MAXILLA (figs. 204–207)</p> <p>Preservation: Most of the right maxilla is present in AMNH 30563, but the ventral margin is missing some of its edges; its medial margin is missing posteriorly. There seems to be a natural edge just behind the premaxilla. The left maxilla only consists of the anterior half of the bone. Its ventral margin is a broken edge. Its medial edge seems to be natural anteriorly, as on the right side. Both maxillae have a posterior broken edge with a very similar shape that is close to where the palatine should be.</p> <p>Contacts of vertical plate: The maxilla contacts the premaxilla anteriorly, the prefrontal anterodorsally, the jugal posterodorsally, and the quadrate posteroventrally. The jugal contact is only presumed, as the bone is ill defined. The quadrate suture is in a broken area, so its exact position is unclear, but it is not possible that another bone could be there.</p> <p>Structures of vertical plate: The maxilla forms the ventral part of the orbital margin. There is a sharp rim with a concave pocket below the internal surface, as in Phosphatochelys and Rhothonemys. Anteriorly the maxilla forms the lateral wall and lateral part of the floor of the fossa nasalis. The orbitonasal bar in Ummulisani is narrow, as in Phosphatochelys, not wide, as in Taphrosphys and other Taphrosphyini.</p> <p>The maxilla in Ummulisani is unusually deep, deeper than other Taphrosphyini except Phosphatochelys. Due to the greater snout foreshortening in Phosphatochelys, Ummulisani has a longer anterior part of the maxilla, as in the other Taphrosphyini. The narrow cheek emargination seen in Phosphatochelys is present but poorly preserved in the type skull of Ummulisani, but it is clearly present in the other two skulls of Ummulisani.</p> <p>Contacts of horizontal plate: The only contact preserved in AMNH 30563 is anteriorly with the premaxilla, but it is possible that the posteromedial broken edge is close to the palatine contact.</p> <p>Structures of horizontal plate: The triturating surface in Ummulisani is relatively narrow, as in other Taphrosphyini and in contrast to the wide surface of the Bothremydini. The labial ridge in Ummulisani is deep, as in Phosphatochelys, but it is very thin and curved, in contrast to the thicker, wedge shape in Phosphatochelys. The entire triturating surface is curved, as in Labrostochelys; it is not a distinct labial ridge meeting a horizontal triturating surface at right angles.</p> <p>The apertura narium interna is represented by a natural edge of the maxilla that is the anterolateral margin of the apertura. This is similar in position to the apertura in Phosphatochelys and Taphrosphys. The maxilla forms the lateral part of the floor of the fossa orbitalis. All the other bones are missing, but the maxilla in Ummulisani does form more of the floor than does the maxilla in Azabbaremys. There is a high, sharp rim to the orbital margin and a ventral pocket formed by the maxilla, as in Rhothonemys and Phosphatochelys.</p> <p>VOMER</p> <p>Preservation: Not preserved in AMNH 30563.</p> <p>PALATINE</p> <p>Preservation: Not preserved in AMNH 30563.</p> <p>QUADRATE (figs. 204–207)</p> <p>Preservation: Both quadrates are present in AMNH 30563; the right one is nearly complete except for damage along its anterior margin, and the left is missing its dorsal portions.</p> <p>Contacts on lateral surface: The quadrate in Ummulisani contacts the quadratojugal dorsomedially and the postorbital anteromedially. The anterior margin of the quadrate is not well preserved and the sutures are not entirely clear. However, the quadrate does contact the jugal anterodorsally and the maxilla anteriorly, as in Phosphatochelys. The quadrate contacts the squamosal posterodorsally.</p> <p>Structures: It is not clear whether the quadrate enters the temporal emargination in Ummulisani due to damage. The degree of emargination is similar in Ummulisani and Phosphatochelys, and Phosphatochelys has no quadrate exposure along the margin. The lateral surface of the quadrate in Ummulisani is expanded anteriorly as in Phosphatochelys, forming much of the cheek. Although the cavum tympani is clearly defined, there is a wider, shallow depression paralleling the anterior curved edge of the cavum. This depression extends well onto the cheek.</p> <p>The cavum tympani in Ummulisani is similar to that in Phosphatochelys. The incisura columellae auris is the usual canal, with the deepest part of the cavum dorsal and anterior to it. The ventral shelf seen in many bothremydids is present, but not as deep or as well defined as in other taxa, such as Bothremys. The antrum postoticum is closed, although the area is a deep concavity posterodorsal to the incisura columellae auris. The sulcus eustachii is a V-shaped notch with a shallow groove extending toward the incisura columellae auris. There is a ventrally directed process on the dorsal edge of the sulcus, as in Phosphatochelys and Labrostochelys. There is also a broken base for a dorsally directed process on the lower margin of the sulcus eustachii on the right quadrate.</p> <p>Contacts on dorsal and anterior surface: On the dorsal surface of the otic chamber, the quadrate contacts the prootic anteromedially, the opisthotic posteromedially, and the squamosal posteriorly. There is no supraoccipital contact, agreeing with the other Taphrosphyini.</p> <p>Structures on dorsal and anterior surface: The foramen stapedio-temporale is only separated from the foramen nervi trigemini by a thin bar. Only a small part of quadrate seems to reach the margin of the foramen stapedio-temporale due to this very medial position. These relations are similar in both Ummulisani and Phosphatochelys.</p> <p>Contacts on ventral surface: The quadrate in Ummulisani contacts the pterygoid anteromedially, the basisphenoid medially, the basioccipital posteromedially, and the exoccipital posteromedially as well. The basisphenoid contact is wide in Ummulisani, as in Taphrosphys and in contrast to the narrow contact of other Taphrosphyini.</p> <p>Structures on ventral surface: There is no fossa pterygoidea in Ummulisani, although there is a slight concavity here. The condylus mandibularis is well anterior to the condylus occipitalis and the basisphenoid-basioccipital suture. On the posterior surface of the condylus mandibularis is a shallow depression for the depressor mandibulae, as in Phosphatochelys, not a deep depression, as in Labrostochelys. The foramen posterius canalis carotici interni is formed completely by the quadrate in Ummulisani. Ummulisani and Labrostochelys are the only pleurodires with the foramen posterius canalis carotici interni entirely formed by the quadrate.</p> <p>Contacts on posterior surface: The quadrate in Ummulisani contacts the squamosal dorsolaterally, the opisthotic dorsomedially, the exoccipital medially, and the basioccipital ventromedially. The exoccipital suture is visible in only a few places.</p> <p>Structures on posterior surface: The fenestra postotica in Ummulisani is fully enclosed by bone, being widely separated from the foramen jugulare posterius. The fenestra postotica is oval, roughly horizontal, with no sign of divisions.</p> <p>PTERYGOID (figs. 204–207)</p> <p>Preservation: Both pterygoids are present, but they lack the processus trochlearis pterygoideus and anterior edges. The left one is missing its lateral edge, which is present on the right.</p> <p>Contacts on ventral surface: The pterygoid in Ummulisani contacts the quadrate posterolaterally, the basisphenoid posteromedially, and the other pterygoid medially. The palatine suture may be represented in a small part of the broken anterior edge, indicating that the pterygoid may not have been much longer than preserved.</p> <p>Structures on ventral surface: There is no deep fossa pterygoidea, only a very shallow, ill-defined depression in the area. The quadrate ramus is slightly more extensive than in Phosphatochelys. There is no sign of the foramen palatinum posterius, as all of the anterior edges of the pterygoids are broken. The foramen posterius canalis carotici interni is entirely formed by the quadrate with no pterygoid participation.</p> <p>Contacts on dorsal surface: The crista pterygoidea of the pterygoid contacts the parietal dorsally and the quadrate posteroventrally below the foramen nervi trigemini. The sutures around the foramen nervi trigemini are not clear, but there seems to be no prootic contact; the parietal enters the margin of the foramen between the pterygoid and prootic.</p> <p>Structures on dorsal surface: The crista pterygoidea rises posteriorly to just anterior to the foramen nervi trigemini where it drops ventrally, and only a small part enters the foramen margin. The pterygoid bears a low, rounded ridge that is oriented anterodorsally–posteroventrally. It extends from a position anterior to the foramen nervi trigemini ventrally along the quadrate ramus paralleling the quadrate-pterygoid suture. In Phosphatochelys this ridge is larger and acute, defining a tubular space anterior to the ridge (see Phosphatochelys, Pterygoid).</p> <p>SUPRAOCCIPITAL (figs. 204, 207)</p> <p>Preservation: The supraoccipital is present and nearly complete in AMNH 30563. There is some breakage along its right anterolateral margin.</p> <p>Contacts: The supraoccipital in Ummulisani contacts the parietals anteriorly, the exoccipitals posteroventrally, the prootic anterolaterally, and the opisthotic posterolaterally. The sutures, however, are not clear on either side, but there is no quadrate contact, agreeing with other Taphrosphyini.</p> <p>Structures: The crista supraoccipitalis in Ummulisani is a very short, blunt process, with little similarity to the usual flat, vertical plate seen in other turtles. Phosphatochelys has a short crista, but it has a clear vertical plate. Ummulisani has a low crista with a blunt posterior end that is only slightly raised above the foramen magnum. The supraoccipital in Ummulisani has a horizontal contribution to the skull roof that extends anteriorly and laterally more than in other bothremydids. Taphrosphys has a wide plate, but not as deep as in Ummulisani.</p> <p>EXOCCIPITAL (figs. 204, 207)</p> <p>Preservation: Both exoccipitals are present and nearly complete in AMNH 30563.</p> <p>Contacts: The exoccipital in Ummulisani contacts the supraoccipital dorsally, the opisthotic laterally, the quadrate ventrolaterally, and the basioccipital ventrally.</p> <p>Structures: The foramen magnum in Ummulisani is about the same as in other</p> <p>Taphrosphyini. The condylus occipitalis is formed entirely by the exoccipitals. There is very little constriction to form a neck for the condyle. The foramen nervi hypoglossi consist of a larger, more medial foramen and a much smaller, more lateral one, as in other Taphrosphyini. As in Phosphatochelys, the more lateral one is very close to the foramen jugulare posterius, although in Ummulisani it is not actually within the margin of the foramen jugulare posterius as it is in Phosphatochelys. The foramen jugulare posterius is completely closed laterally by the opisthotic-exoccipital contact. The foramen is recessed, with a blunt shelf below, so that it faces more laterally than the foramen does in Phosphatochelys.</p> <p>BASIOCCIPITAL (figs. 204–207)</p> <p>Preservation: The basioccipital in AMNH 30563 is nearly complete.</p> <p>Contacts: The basioccipital in Ummulisani contacts the basisphenoid anteriorly, the quadrate in a wide suture laterally, and the exoccipital posterolaterally.</p> <p>Structures: Ummulisani has a blunt, low tuberculum basioccipitale formed by the basioccipital and exoccipital that is similar in size and extent to that in Labrostochelys and is lower than that in Phosphatochelys. There is a shallow concavity on the midline, much the same as in other Taphrosphyini.</p> <p>PROOTIC (figs. 204, 207)</p> <p>Preservation: Both prootics in AMNH 30563 are present and nearly complete, but some of the sutures are dim.</p> <p>Contacts: The prootic in Ummulisani contacts the parietal dorsomedially, the quadrate laterally, the supraoccipital posterodorsally, and the opisthotic posteriorly.</p> <p>Structures: The prootic forms a thin bar separating the foramen nervi trigemini from the foramen stapedio-temporale. In Ummulisani the two foramina are not sunk into a common recess, as in Taphrosphys, but are still very close, as in Phosphatochelys. The prootic forms most of the foramen stapedio-temporale. The foramen stapedio-temporale faces mostly anteriorly and the foramen nervi trigemini faces mostly laterally.</p> <p>OPISTHOTIC (figs. 204–207)</p> <p>Preservation: Both opisthotics are present in AMNH 30563. The left one is damaged along its posterolateral margin; the right one is also damaged posterolaterally and medially as well, so that some of the sutures are obscured.</p> <p>Contacts: The opisthotic in Ummulisani contacts the supraoccipital anteromedially, the prootic anteriorly, the quadrate anterolaterally, the exoccipital posteromedially, and the squamosal posterolaterally, although much of this latter contact is obscured by breakage.</p> <p>Structures: The opisthotic enters into the fenestra postotica (see Quadrate) and the foramen jugulare posterius. The opisthotic is part of a posterior flange that, along with the squamosal, forms a ventrally open trough similar to that seen in Labrostochelys and Taphrosphys, and, to a lesser extent, in Phosphatochelys.</p> <p>BASISPHENOID (figs. 204–207)</p> <p>Preservation: The basisphenoid in AMNH 30563 is present and complete ventrally. Its dorsal surface has some damage and is partially obscured by matrix.</p> <p>Contacts on ventral surface: The basisphenoid in Ummulisani contacts the pterygoids anterolaterally, the basioccipital posteriorly, and the quadrate in a wide suture laterally.</p> <p>Structures on ventral surface: The basisphenoid in Ummulisani is pentagonal and similar in shape to that in Taphrosphys. However, its anterior margin does have a point on the midline, similar to that in Phosphatochelys.</p> <p>Contacts on dorsal surface: Not determinable.</p> <p>Structures on dorsal surface: The rostrum basisphenoidale is fused into a single rod anterior to the sella turcica. The sella seems to be wide, not narrow as in Taphrosphys congolensis. The dorsum sellae seems to be damaged, but was probably higher than in T. sulcatus.</p> <p>Rhothonemys brinkmani</p> <p>The single skull representing this species is incomplete, lacking most of the palate and basicranium. Rhothonemys is the sister group to Phosphatochelys + Ummulisani.</p> <p>PREFRONTAL (figs. 208–211)</p> <p>Preservation: Both prefrontals are present in AMNH 30521, with both surfaces visible. The left prefrontal lacks its anteromedial edge and the right one has a small broken area ventrally. The right prefrontal is missing some of the ventral margin of its ventral process.</p> <p>Contacts: The prefrontal in Rhothonemys contacts the maxilla anteroventrally, the frontal posteriorly, and the other prefrontal medially. There is no parietal contact, as in Phosphatochelys, or a palatine contact, as in Bothremys and Chedighaii.</p> </div>	https://treatment.plazi.org/id/4E7B8791CE1BFE72FC99FA5314968C84	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	GAFFNEY, EUGENE S;TONG, HAIYAN;MEYLAN, PETER A	GAFFNEY, EUGENE S, TONG, HAIYAN, MEYLAN, PETER A (2006): EVOLUTION OF THE SIDE-NECKED TURTLES: THE FAMILIES BOTHREMYDIDAE, EURAXEMYDIDAE, AND ARARIPEMYDIDAE. Bulletin of the American Museum of Natural History 300 (300): 1-698, DOI: 10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2, URL: http://dx.doi.org/10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2
4E7B8791CEA7FD83FF58FB0B11F1896A.text	4E7B8791CEA7FD83FF58FB0B11F1896A.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Rhothonemys Gaffney & Tong & Meylan 2006	<div><p>Structures: The prefrontal in Rhothonemys is relatively large, being larger than the frontal and similar in relative size to the prefrontal in Phosphatochelys. The prefrontal in Rhothonemys protrudes anteromedially, as in Phosphatochelys, producing a blunt point on the midline. In Rhothonemys the degree of protrusion is more extensive than in Phosphatochelys, also correlated with the larger size of the apertura narium externa. The posterior margin of the prefrontal in Rhothonemys is straight, as in Taphrosphys, not indented, as in Phosphatochelys, due to the very small frontal in that taxon. The prefrontal in Rhothonemys forms the anterodorsal margin of the orbit, as in Taphrosphys, but does not extend posteriorly to the degree seen in Phosphatochelys. The interorbital distance in Rhothonemys is much narrower than in Phosphatochelys and Azabbaremys; it is similar in relative width to Taphrosphys.</p> <p>The ventral process of the prefrontal in Rhothonemys separates the very large fossa nasalis from the fossa orbitalis. The process is similar in extent in Rhothonemys and Phosphatochelys but is thinner than in Pelomedusidae and Cearachelyini. The ventral surface of the prefrontal in Rhothonemys forms the roof of the large fossa nasalis and is broadly concave ventrally on each side of the midline (fig. 211A). The shape of this paired depression is more distinct than in Phosphatochelys, Pelomedusidae, and Cearachelyini.</p> <p>FRONTAL (figs. 208–211)</p> <p>Preservation: Both frontals are present in AMNH 30521, and dorsal and ventral surfaces are visible. The parasagittal ridge delimiting the sulcus olfactorius is broken along its ventral margin in both prefrontals. A small part of the orbital edge is broken posteriorly on both prefrontals, but most of the edge is intact.</p> <p>Contacts: The frontal in Rhothonemys contacts the prefrontal anteriorly, the parietal posteriorly, and the other frontal medially. In most bothremydids the frontal also contacts the postorbital, but in Rhothonemys the contact is separated by the parietal exposure in the orbital margin. In Phosphatochelys the contact is also lacking, due to the small size of the frontal and the broad prefrontal-parietal contact.</p> <p>Structures: The frontal in Rhothonemys forms the dorsal part of the orbital margin, much as in Taphrosphys, and in strong contrast to Phosphatochelys, in which the frontal is widely separated from the orbital margin by the parietal-prefrontal contact. The frontal is smaller than the prefrontal in Rhothonemys, as it is in Phosphatochelys. In Taphrosphys, Azabbaremys, and Nigeremys, it is equal to or larger than the prefrontal. In Labrostochelys the prefrontal is very elongate.</p> <p>The ventral surface of the frontal in Rhothonemys (fig. 211A) shows the anteromedial projection, actually broken off on both sides but determinable from the sutural surface on the prefrontal, extending under the prefrontal, as occurs in most bothremydids and many pleurodires. The parasagittal ridge, although incomplete, separating the sulcus olfactorius from the fossa nasalis is about the same size as in other bothremydids, such as Galianemys. The sulcus in Phosphatochelys seems to be formed by the parietal rather than the frontal.</p> <p>PARIETAL (figs. 208–211)</p> <p>Preservation: Both parietals are present in AMNH 30521, but they are incomplete ventrally, posteriorly, and laterally. On the left side, the posterior temporal roof margin is broken and slightly displaced, but it seems to have its natural edge posteriorly. Ventrally, only the dorsalmost part of the processus inferior parietalis is preserved. None of the actual supraoccipital contact is preserved.</p> <p>Contacts of dorsal plate: The parietal in Rhothonemys contacts the frontal anteriorly, the other parietal medially, and the supraoccipital posteroventrally (displaced and filled with matrix). The postorbital contact is present on the left side and seems to run the length of the parietal. However, the sutures are difficult to discern and a quadratojugal suture cannot be made out, so some of this contact may be the quadratojugal.</p> <p>Structures of dorsal plate: The edge of the temporal emargination is preserved partially on the left side. Although slightly displaced, the degree of emargination in Rhothonemys is similar in extent to that seen in Phosphatochelys and Azabbaremys, but it is less emarginate than in Taphrosphys.</p> <p>The ventral surface of each parietal is visible in AMNH 30521 (fig. 211), and it has the ridges where the processus inferior parietalis and the fossa orbitalis form walls separating these spaces. Only the dorsal attachment ridges are present; the walls are broken off. The parietal in Rhothonemys is relatively farther forward in the skull roof than it is in all other Pelomedusoides except Phosphatochelys. This is also expressed in the exposure of the parietal in the orbital margin in Rhothonemys and Phosphatochelys. The parietal in Rhothonemys, Phosphatochelys, and Taphrosphys forms a pocket in the posterior part of the fossa orbitalis, posterior to the orbital margin and anterior to the septum orbitotemporale ridge (all that remains of this wall). In Rhothonemys this pocket (fig. 211) has its walls broken away, but it is very similar to that in Taphrosphys sulcatus (fig. 170C) and T. ippolitoi (fig. 183B).</p> <p>Contacts and structures of processus inferior parietalis: The processus inferior parietalis in AMNH 30521 is largely missing, and its ventral contacts and structures cannot be determined.</p> <p>JUGAL (figs. 208–211)</p> <p>Preservation: Both jugals are present in AMNH 30521, but neither is complete. The left one is lacking some of its anterodorsal area, where it forms the orbital margin, and some of its medial process appears broken. The right jugal is preserved along its contact with the maxilla, but its posterodorsal area and most of its medial process are missing. The posterior margin of the right jugal is intact, but the left one is a broken surface.</p> <p>Contacts of lateral plate: The anteroventral contact with the maxilla in Rhothonemys runs from the posteroventral orbital margin to the edge of the narrow cheek emargination as in Phosphatochelys. The posterior edge of the jugal is exposed on the cheek emargination ventrally, but dorsally its contacts are broken in AMNH 30521. Dorsally, the jugal contacts the postorbital, and although broken, this can be seen on the left side. Posterodorsally, it is likely that the jugal contacts the quadrate and/or the quadratojugal, but this cannot be determined due to crushing and missing bone in this area.</p> <p>Structures of lateral plate: The fossa orbitalis in Rhothonemys forms a large pock- et ventral to the orbital margin (fig. 211). This pocket is also found in Phosphatochelys and Taphrosphys but not, as far as can be seen in the flattened specimens, Labrostochelys. In Rhothonemys the jugal forms the posterior half of the suborbital pocket; the maxilla forms the anterior half. The jugal in Rhothonemys and Phosphatochelys is relatively deep dorsoventrally, in contrast to the much shallower jugal in Taphrosphys and Labrostochelys. The suborbital pocket in Rhothonemys is deeper than in Phosphatochelys. These pockets are more accurately considered to be one feature, an expanded fossa orbitalis formed by multiple bones (jugal, postorbital, parietal, maxilla), although it is convenient to describe and label the particular areas as separate. In the character descriptions, the fossa orbitalis enlargement is considered one character, character 27.</p> <p>The posterior margin of the jugal in Rhothonemys seems to be a free edge, ending in an acute ridge, not a sutural margin. This is very similar to the jugal in Phosphatochelys, which also has a free posterior margin. In Rhothonemys the dorsal and posterior elements of this cheek emargination are not known due to crushing and bone loss, but there does not seem to be room for a large quadratojugal or a large cheek emargination. The free edge on the jugal runs dorsally almost to the postorbital contact.</p> <p>Contacts of medial process: Both jugals in Rhothonemys have no preserved contacts medially. The left jugal has a sutural surface on the medial edge of the medial process. This is presumably for the pterygoid and palatine contacts. The medial process does not really have a horizontal contact with the maxilla as in other Pelomedusoides; only the lateral plate of the jugal does. The lateral plate contacts the postorbital dorsally, but the medial jugal process is present only ventrally, so the postorbital does not participate in the reduced septum orbitotemporale. This condition also occurs in Phosphatochelys and Azabbaremys (the latter entirely lacks the septum orbitotemporale).</p> <p>Structures of medial process: The jugal medial process in Rhothonemys is well developed ventrally, but incomplete more dorsally, so that the upper half of the septum orbitotemporale is largely absent, in contrast to bothremydids outside the Taphrosphyini. The medial process of the jugal is even smaller in Phosphatochelys and Azabbaremys. It is present but poorly preserved in Taphrosphys and Labrostochelys. The fossa orbitalis in Rhothonemys has a deep ventral pocket that is defined posteroventrally by the medial jugal process, but posterodorsally it is likely that the fossa is open. Nonetheless, the medial process in Rhothonemys is higher and extends farther medially than it does in Phosphatochelys.</p> <p>QUADRATOJUGAL (figs. 208–210)</p> <p>Preservation: The position and identification of the quadratojugal in AMNH 30521 is problematic. The posterolateral part of the skull roof is mostly missing on the right side and is cracked and poorly preserved on the left. The best guess for the quadratojugal is a plate of bone on the left side lying lateral to the parietal on the posterior margin of the temporal roof. The medial margin is a suture with the parietal; the lateral margin is a broken edge connecting to the quadrate. The anterior margin is a large crack, with no clear sign of a sutural contact. If Rhothonemys is similar to Phosphatochelys, then this plate of bone is in the same place as the quadratojugal in Phosphatochelys. However, if Rhothonemys is like Azabbaremys, the plate of bone is the posterior continuation of the postorbital and the quadratojugal is a small element, largely lost in the crushed and broken area lateral to the postorbital. However, careful examination of this area does not show any sutural edges either, and there does not seem to be enough bone missing to make up a complete quadratojugal, hence the identifications in figure 210 and the restoration in figure 208. It is still just a guess, though.</p> <p>Contacts and structures: If this plate of bone is the quadratojugal, it is similar in contacts to those in Phosphatochelys and Taphrosphys, contacting the parietal medially, the postorbital anteriorly, and the quadrate laterally. The quadratojugal forms the lateral part of the temporal margin.</p> <p>SQUAMOSAL (figs. 208–210)</p> <p>Preservation: Most of the left squamosal and a small portion of the right squamosal are present in AMNH 30521. The left squamosal lacks its dorsal and posterior margins. Only the part of the right squamosal immediately posterior to the quadrate is preserved, and this is broken by crushing.</p> <p>Contacts: The squamosal in Rhothonemys contacts the quadrate anteriorly and anteromedially and the opisthotic medially. A possible anterodorsal contact with the quadratojugal is indeterminate due to missing bone.</p> <p>Structures: The squamosal forms the cone-shaped outer bone for the antrum postoticum. In Rhothonemys the antrum is ‘‘moderate’’, similar in size to Phosphatochelys and Taphrosphys, larger than in Labrostochelys, and not absent, as in Azabbaremys. The posterior limit of the squamosal is a broken edge on both sides, but it does not seem to be trending into a very elongated shape like that in Labrostochelys. There is a well-developed vertical flange on the ventral surface of the squamosal, as in Phosphatochelys, Labrostochelys, and Taphrosphys. The lateral tubercle also seen in these three genera is not determinable in Rhothonemys, as the anterolateral part of the squamosal is broken off.</p> <p>POSTORBITAL (figs. 208–210)</p> <p>Preservation: The area of the skull roof in AMNH 30521 posterior to the orbits is poorly preserved on both sides. On the right side only broken pieces of bone in the matrix are present that seem to be postorbital fragments, and no sutures are visible. On the left side, the anterodorsal and anteroventral areas of the postorbital are preserved and defined by sutures, but they are separated from each other by matrix. Posteriorly the postorbital is not clearly defined by sutures except medially, where it lies along the parietal. Most of its lateral edge is a broken margin. Posteriorly, a crack separates the postorbital from what may be the quadratojugal (see Quadratojugal) or a continuation of the postorbital. Either interpretation is possible, although the former is slightly more likely.</p> <p>Contacts of lateral plate: The postorbital in Rhothonemys contacts the parietal medially for its entire length and the jugal anterolaterally. Posteriorly it may contact the quadratojugal (see Quadratojugal). The postorbital lateral contacts are dubious, but it is probable that there was a quadrate contact, as in Phosphatochelys.</p> <p>Structures of lateral plate: The postorbital in Rhothonemys forms that posterodorsal margin of the orbit. If the quadratojugal is present behind the postorbital, then the postorbital does not reach the temporal margin. If there is no suture, however, then the postorbital extends posteriorly to the temporal margin, as in Azabbaremys.</p> <p>Contacts and structures of medial process: The postorbital in AMNH 30521 is not well enough preserved to determine all the features of the medial process. The ventral portion of the internal postorbital surface is preserved on the left side, and it shows that the medial process is absent; there is no medial contact with another bone. The septum orbitotemporale is small or absent.</p> <p>PREMAXILLA (figs. 208–211)</p> <p>Preservation: The premaxilla in AMNH 30521 is present on both sides, but both lack the posterior projection.</p> <p>Contacts: The premaxilla in Rhothonemys contacts the maxilla posterolaterally and the other premaxilla medially. A posteri- or contact with a vomer is indeterminate.</p> <p>Structures on dorsal surface: The premaxilla in Rhothonemys forms the ventral margin of the very large apertura narium externa. On the midline there is a dorsal projection of both premaxillae that forms a midline separation of the apertura. This internarial process has a broken dorsal margin on both sides, but the broken area seems too small to support a complete internarial bar, particularly on the left side. It is likely that the apertura narium externa in Rhothonemys was not divided on the midline.</p> <p>On the anterior surface of the premaxilla, the bone slopes dorsally into the apertura narium externa, very similar to Phosphatochelys. This condition also occurs on the maxilla of Rhothonemys (see Maxilla), but it is not so apparent on the Phosphatochelys maxilla.</p> <p>Structures on ventral surface: The labial ridge on the premaxilla in Rhothonemys is thick in comparison to most other Taphrosphyini (e.g., Phosphatochelys), but it is not as thick as in Azabbaremys. The actual edge of the labial ridge, however, is acute, not blunt. The internal surface of the premaxilla in Rhothonemys is nearly vertical but slightly concave. This concave surface continues the concave surface on the maxilla. The external surface of the labial ridge is convex, curving anterodorsally to meet the low, horizontal ridge that marks the beginning of the indented surface surrounding the apertura narium externa. The medial horizontal process of the premaxilla in Rhothonemys is missing.</p> <p>MAXILLA (figs. 208–211)</p> <p>Preservation: Both maxillae are present in AMNH 30521, but both lack most of their horizontal plate.</p> <p>Contacts of vertical plate: The vertical plate of the maxilla in Rhothonemys contacts the premaxilla anteromedially, the jugal posterodorsally, and the prefrontal anterodorsally. The posterior margin of the maxilla below the jugal is a free edge, so there is no quadratojugal or quadrate contact.</p> <p>Structures of vertical plate: The orbital margin in Rhothonemys is an acute ridge, well dorsal to the floor of the fossa orbitalis, in contrast to the low, blunt orbit of forms like Bothremys cooki. The orbit is placed high on the cheek in Rhothonemys, so that the maxilla is unusually deep, deeper than in any other bothremydid, although Phosphatochelys and Azabbaremys approach this condition. The maxilla in Rhothonemys is relatively large and forms a greater part of the cheek than in any other bothremydid.</p> <p>The maxilla forms the lateral margin of the apertura narium externa. This margin in Rhothonemys is very high and the apertura is very large, relatively larger than in any other bothremydid. The maxilla bears a slightly recessed area around the margin of the apertura narium externa, as on the premaxilla. There is a similar, indistinct recessed area around the apertura in Phosphatochelys, but not in other bothremydids. It is possible that this is the attachment area for a large proboscis, showing that Rhothonemys is really an elephant. The fossa nasalis is not completely preserved in Rhothonemys, but the internal surface of the maxilla shows the approximate extent. As expected from the larger apertura, the fossa nasalis is also large, although not significantly larger than in some other Taphrosphyini.</p> <p>Contacts and structures of horizontal plate: Most of the horizontal or medial plate of the maxilla in AMNH 30521 is missing, but its lateral position on the vertical plate and some structures are preserved. The contacts are not preserved.</p> <p>The labial ridge, actually formed more by the horizontal plate, is an acutely edged ridge that becomes thick dorsally and is slightly concave on its medial surface. The labial ridge in Rhothonemys is unique in shape among bothremydids; it is thicker than in Phosphatochelys, Labrostochelys, and Taphrosphys and has a different cross section than in Arenila and Nigeremys. The cross section with a broadly curved outer surface and a concave inner surface is not found in other pleurodires. The maxilla and premaxilla labial ridge morphologies are the same.</p> <p>Although most of the lingual ridge is missing in AMNH 30521, a small portion is preserved on both sides. This shows a very low lingual ridge and a narrow triturating surface, broadly curved from labial to lingual ridge, similar to Labrostochelys. The surface, however, has a series of very low, dorsoventral ridges. The narrow triturating surface of the maxilla is consistent with the narrow lower jaw associated with the skull of AMNH 30521.</p> <p>The fossa orbitalis in Rhothonemys (fig. 211) has a large pocket formed anterior and ventral to the orbital margin. This pocket, although smaller, also occurs in Phosphatochelys and Taphrosphys. Combined with the posterodorsal parietal pocket, the result is an unusually large fossa orbitalis in Rhothonemys, even larger than that in Chedighaii. At the posteroventral corner of the fossa orbitalis, just anterior to the jugal suture, is a large foramen leading into a canal in the maxilla. This seems to be the foramen supramaxillare, or at least the foramen identified as this in Gaffney (1979a: fig. 54).</p> <p>VOMER AND PALATINE</p> <p>Preservation: The vomer and the palatine are not preserved in AMNH 30521.</p> <p>QUADRATE (figs. 208–210)</p> <p>Preservation: Parts of both quadrates are present in AMNH 30521, but both are incomplete. The right quadrate has only the antrum postoticum portion of the cavum tympani present. The left quadrate has all of the central part of the cavum tympani, incisura columellae auris, antrum postoticum, and sulcus eustachii, but none of its margins. All of its dorsal surface is preserved, but only part of the ventral surface, and the entire processus articularis is missing.</p> <p>Contacts on lateral surface: At least anterodorsally, the quadrate contacts the postorbital and the squamosal posterodorsally. Poor preservation makes the position of the quadratojugal unclear, but it is likely that the quadrate contacts it dorsally, as in Phosphatochelys. Because the maxilla ends posteriorly in a free edge, there is no quadrate-maxilla contact. The ventral part of the jugal is also a free edge, but there may have been a quadrate contact above it, as in Phosphatochelys.</p> <p>Structures on lateral surface: The dorsal edge of the quadrate is a broken margin, and it looks as if the quadrate were not exposed on the temporal margin, but this is unclear.</p> <p>The cavum tympani shows a centrally located incisura columellae auris that is a foramen leading medially into the canal typical of bothremydids. The sulcus eustachii is an indentation or groove in the posteroventral margin of the cavum tympani, as in Phosphatochelys and Azabbaremys and other Taphrosphyini. The antrum postoticum of Rhothonemys is similar in size to that in Phosphatochelys and Taphrosphys, not very small, as in Labrostochelys, or absent, as in Azabbaremys. The edges of the sulcus eustachii are damaged, but it looks as if the ventral process, as found in Phosphatochelys, Labrostochelys, and Taphrosphys, was present.</p> <p>Contacts on dorsal and anterior surfaces: The quadrate contacts in AMNH 30521 are not entirely clear due to poor preservation and possible fusion. The quadrate contacts the opisthotic posteromedially and the squamosal posterolaterally. The area of the prootic is damaged (only the left side preserves this area), but it looks as if there is no quadrate-supraoccipital contact and that the prootic contacts the opisthotic. This would be consistent with other Taphrosphyini. The anterior surface of the quadrate is missing ventrally and is partially covered by matrix.</p> <p>Structures on dorsal and anterior surfaces: The foramen stapedio-temporale and the foramen nervi trigemini in Rhothonemys are below the broken edge and are missing.</p> <p>Contacts and structures on ventral surface: This area, containing the foramen posterius canalis carotici interni and condylus mandibularis as well as pterygoid, basisphenoid, and basioccipital contacts, is missing. The broken surface through this area is poorly preserved.</p> <p>Contacts on posterior surface: The quadrate contacts the opisthotic dorsomedially, the exoccipital medially, and the squamosal dorsolaterally, but other contacts are not preserved.</p> <p>Structures on posterior surface: AMNH 30521 is broken off below the level of the fenestra postotica. However, the quadrate makes up the lateral half of that foramen; it is not subdivided for the stapedial artery and lateral head vein. Lateral to the fenestra postotica is a posteroventrally facing concavity that seems to have contained a bend in the lateral head vein in Rhothonemys. This concavity is not seen in Phosphatochelys or other Taphrosphyini.</p> <p>PTERYGOID</p> <p>Preservation: It is likely that some of the pterygoid in AMNH 30521 is present in the broken surface of the otic chamber, but no sutures or structures can be made out.</p> <p>SUPRAOCCIPITAL (figs. 208–210)</p> <p>Preservation: Most of the supraoccipital in AMNH 30521 is probably present, but it is crushed and poorly preserved. The crista supraoccipitalis is preserved only at its base.</p> <p>Contacts: The supraoccipital in Rhothonemys contacts the parietal anterodorsally. It seems to be exposed on the skull roof just behind the parietals. The supraoccipital contacts the exoccipitals posteroventrally and the opisthotics posterolaterally. Although not definite, the supraoccipital seems to contact the prootic anterolaterally with no quadrate contact.</p> <p>Structures: The base of the crista supraoccipitalis in Rhothonemys, even though crushed, shows a plate that is lower in height than the one in Phosphatochelys. The foramen magnum is present but crushed, obscuring its shape.</p> <p>EXOCCIPITAL (figs. 208–210)</p> <p>Preservation: The dorsal part of the left exoccipital and pieces of the right one are preserved in AMNH 30521.</p> <p>Contacts: The exoccipital in Rhothonemys contacts the supraoccipital dorsally and the opisthotic laterally. The other contacts are missing.</p> <p>Structures: The left exoccipital in Rhothonemys preserves some of the foramen magnum margin and the dorsal half of the foramen jugulare posterius. The foramen is closed laterally and separated by bone from the fenestra postotica. The condylus occipitalis is missing.</p> <p>BASIOCCIPITAL</p> <p>Preservation: None of the basioccipital is preserved in AMNH 30521.</p> <p>PROOTIC (fig. 210)</p> <p>Preservation: The left prootic is present in AMNH 30521, but sutures defining it are questionable due to poor preservation and crushing in this area.</p> <p>Contacts and structures: The prootic in Rhothonemys contacts the quadrate laterally and the supraoccipital posterodorsally, but the opisthotic contact is questionable. The ventral half is missing. The foramen stapedio-temporale, foramen nervi trigemini, and other structures are not preserved.</p> <p>OPISTHOTIC (figs. 208–210)</p> <p>Preservation: The left opisthotic in AMNH 30521 is present and only missing some of its posterior margin. The right one is preserved dorsally but broken posteriorly and ventrally.</p> <p>Contacts: The opisthotic in Rhothonemys contacts the supraoccipital anteromedially, the quadrate anterolaterally, the squamosal posterolaterally, and the exoccipital posteromedially. There is probably an anterior contact with the prootic.</p> <p>Structures: The opisthotic in Rhothonemys forms much of the roof of the fenestra postotica. The fenestra is not subdivided (see Quadrate). The opisthotic forms the lateral wall of the foramen jugulare posterius. There is no ventrally opening groove on the opisthotic, as in Taphrosphys.</p> <p>BASISPHENOID</p> <p>Preservation: The basisphenoid is not preserved in AMNH 30521.</p> <p>Azabbaremys moragjonesi</p> <p>The single skull that represents this species is a large, well-preserved, uncrushed specimen that shows internal morphology. It was described by Gaffney, Moody, and Walker (2001), which is modified and expanded here. Azabbaremys is the sister taxon to an undescribed skull, CNRST SUNY 199, and in turn they are sister taxa to the remaining Taphrosphyina, with Nigeremys and Arenila outside this group.</p> <p>PREFRONTAL (figs. 212, 215, 280A)</p> <p>Preservation: Both prefrontals in BMNH R16370 are present and complete. The sutures are clearly defined and the dorsal and ventral surfaces are visible.</p> <p>Contacts: The prefrontal in Azabbaremys contacts the maxilla anteroventrolaterally, the frontal posteriorly, and the other prefrontal medially.</p> <p>Structures: The prefrontal in Azabbaremys is a relatively large element, forming most of the preorbital part of the skull in dorsal view. In contrast to the small prefrontals of pelomedusids and Araripemys, Azabbaremys and most bothremydids have a broad preorbital area and a large prefrontal. The dorsal surface is convex, forming most of the distinctive dorsal protuberance of the nose found in Azabbaremys. The ventral surface is broadly concave, without a distinctly defined sulcus olfactorius.</p> <p>The prefrontal of Azabbaremys forms the anterior margin of the fossa orbitalis, as in other Pelomedusoides; however, in Azabbaremys the prefrontal has a well-developed posteroventral portion that occupies the area formed by the maxilla in other Pelomedusoides. This part of the prefrontal is comparable in extent to Taphrosphys and possibly Arenila, although the sutures are ambiguous in the latter. Ventrally the prefrontal contacts the maxilla in a nearly horizontal suture at the level of the ventral margin of the orbit. The anterior margin of the prefrontal forms the dorsal margin of the apertura narium externa, which is protuberant in Azabbaremys so that the dorsal margin overhangs the apertura, much as in Taphrosphys. The protuberance is broad, extending the entire width of the apertura.</p> <p>FRONTAL (figs. 212, 215)</p> <p>Preservation: Both frontals in BMNH R16370 are present and complete. The sutures are clearly defined and the dorsal and ventral surfaces are visible.</p> <p>Contacts: The frontal in Azabbaremys contacts the prefrontal anteriorly, the other frontal medially, the parietal posteriorly, and the postorbital posterolaterally. It forms the dorsal margin of the fossa orbitalis between the prefrontal and postorbital contacts.</p> <p>Structures: The dorsal surface of the frontal in Azabbaremys is broadly convex, continuing the convexity formed by the prefrontal.</p> <p>On the ventral surface the frontal forms a deep and well-developed sulcus olfactorius. The parasagittal ridge is low anteriorly, beginning as a continuation of the prefrontal ridge that divides the fossa orbitalis from the fossa nasalis. The sulcus olfactorius ridge deepens posteriorly as it merges into the processus inferior parietalis. The orbits of Azabbaremys are widely separated and the margins are almost vertical, a strong contrast to other bothremydids such as Bothremys and Rosasia, which have orbits that face primarily dorsally. Nigeremys and Arenila have orbits with a more lateral orientation, but they do not approach the Azabbaremys condition.</p> <p>PARIETAL (figs. 212, 215, 217)</p> <p>Preservation: Both parietals in BMNH R16370 are present and complete. Sutures are clear on the dorsal surface. The right parietal is visible ventrally, but the left one has matrix on its ventral surface.</p> <p>Contacts of dorsal plate: The dorsal plate of the parietal in Azabbaremys contacts the frontal anteriorly, the other parietal medially, and the postorbital laterally.</p> <p>Structures of dorsal plate: The posterior edge of the parietal in Azabbaremys forms part of the anterior margin of the temporal emargination. The margin is a nearly straightedge trending anterolaterally along the parietal and continuing onto the postorbital. The temporal roof in Azabbaremys is relatively extensive, with most of the otic chamber being covered in dorsal view. In comparison to other bothremydids, the roof in Azabbaremys is more extensive, although Nigeremys approaches it. Nonetheless, the size and shape of the parietal itself are quite similar in Azabbaremys and Taphrosphys.</p> <p>Contacts of processus inferior parietalis: Posteriorly the parietal in Azabbaremys lies above the supraoccipital, as in other turtles. The prootic contacts the parietal from midway along the supraoccipital suture and extends anteroventrally to the foramen nervi trigemini. In Azabbaremys the foramen nervi trigemini is preserved but damaged on both sides. As preserved, the parietal narrowly enters the foramen margin dorsally. The pterygoid forms nearly all of the anterior and ventral margins, with the prootic forming the posterior margin. The complete extent of the foramen is not known posteriorly due to damage.</p> <p>Structure of processus inferior parietalis: The processus inferior parietalis in Azabbaremys is present on both sides, with medial and lateral surfaces being visible. It is unusually narrow, in strong contrast to pelomedusids, podocnemidids, and most bothremydids, but in common with Taphrosphys. The condition in Arenila and Nigeremys is indeterminate. The parietal extends ventrally, forming the processus inferior parietalis, and meets the crista pterygoidea of the pterygoid in a suture that drops anteroventrally from the foramen nervi trigemini to the edge of the processus inferior parietalis (fig. 217). The anterior margin of the processus forms the posterior margin of the foramen interorbitale. As a consequence of the high, arched palate, the deep sulcus olfactorius, and the short snout, the foramen interorbitale is relatively small in Azabbaremys.</p> <p>JUGAL (figs. 212, 215, 280A)</p> <p>Preservation: Both jugals in BMNH R16370 are present and complete. The sutures are clearly defined and the internal and external surfaces are visible except for a small area on the inside of the left jugal.</p> <p>Contacts of lateral plate: The external or vertical plate of the jugal in Azabbaremys contacts the postorbital dorsally, the quadratojugal posterodorsally, the quadrate posteriorly, and the maxilla ventrally. The quadrate contact is found throughout the Taphrosphyini.</p> <p>Structures of lateral plate: The jugal forms the posteroventral margin of the orbit in Azabbaremys. It is exposed to a greater extent than the jugal in Nigeremys and Arenila (Lapparent de Broin and Werner, 1998).</p> <p>Contacts of medial process: The medial process of the jugal in Azabbaremys forms part of the septum orbitotemporale and contacts the palatine medially and the maxilla ventrally.</p> <p>Structures of medial process: As in other Taphrosphyini, the jugal does not extend onto the triturating surface in Azabbaremys. The jugal forms part of the floor of the fossa orbitalis, contacting the maxilla anteriorly and the palatine medially (fig. 280A).</p> <p>QUADRATOJUGAL (figs. 212, 215)</p> <p>Preservation: Both quadratojugals are present and complete in BMNH R16370, but both have some damage due to cracking, and the sutures are not all clear.</p> <p>Contacts: The quadratojugal of Azabbaremys contacts the postorbital dorsomedially, the jugal anteroventrally, the squamosal posteriorly, and the quadrate ventrally. In both Phosphatochelys and Taphrosphys the quadratojugal has a parietal contact, absent in Azabbaremys.</p> <p>Structures: In the Bothremydini and Cearachelyini the quadratojugal is a large element extending from the ventral margin of the cheek to the temporal emargination on the skull roof. In Azabbaremys and other Taphrosphyini the quadratojugal is smaller and retracted dorsally above the quadrate, not exposed on the cheek edge, but it still enters the edge of the temporal emargination. Rosasia also has a retracted quadratojugal with no exposure on the cheek edge. The ventral edge of the quadratojugal in Azabbaremys contacts the quadrate. Just dorsal to this suture the edge of the concave cavum tympani extends up onto the quadratojugal. It is unusual in turtles to have the quadratojugal form a significant portion of the cavum tympani, and this does not occur in any other pleurodire.</p> <p>SQUAMOSAL (figs. 212, 215, 218, 281, 286A)</p> <p>Preservation: Both squamosals are preserved in BMNH R16370, but they are missing parts of their posterolateral margins. The right squamosal is more complete posteriorly, but it has breakage on its anterolateral process.</p> <p>Contacts: The squamosal in Azabbaremys is the usual cone-shaped (but apparently not hollow) element sitting on the posterolateral corner of the quadrate, as in most turtles. It contacts the opisthotic medially on the dorsal, posterior, and ventral surfaces. A short process of the squamosal contacts the quadratojugal along the lateral edge of the temporal emargination. All of these contacts are as in pelomedusids, podocnemidids, and other bothremydids.</p> <p>Structures: The squamosal in Azabbaremys is cone-shaped and relatively smooth, not flat, as in Pelusios. Azabbaremys lacks the ventral, parasagittal flange or process of the squamosal characteristic of Taphrosphys. The antrum postoticum is absent in Azabbaremys, and there is no depression on the cavum tympani (figs. 281, 286A). The squamosal is presumably solid, not hollow, as in other turtles.</p> <p>POSTORBITAL (figs. 212, 215)</p> <p>Preservation: Both postorbitals in BMNH R16370 are present and complete. The sutures are clearly defined and the internal surface is visible on the right side.</p> <p>Contacts of lateral plate: The postorbital in Azabbaremys is a large, quadrangular element contacting the frontal anteromedially, the parietal posteromedially, the jugal anterolaterally, and the quadratojugal posterolaterally.</p> <p>Structures of lateral plate: The postorbital forms the posterior margin of the orbit and the anterior edge of the temporal emargination. In the other Taphrosphyini in which the postorbital is completely known (Phosphatochelys, Taphrosphys, Labrostochelys), the postorbital is shorter and does not reach the temporal margin.</p> <p>Contacts and structures of medial process: In most Pelomedusoides, the postorbital has a medial process that contacts the jugal and palatine to form the septum orbitotemporale, which is particularly large in the Bothremydini. In Azabbaremys this wall is absent, and the medial and ventral surfaces of the postorbital are smooth. An absent or reduced septum orbitotemporale is also seen in Taphrosphys, Phosphatochelys, and Rhothonemys, but not in Arenila and Nigeremys.</p> <p>PREMAXILLA (figs. 212–216)</p> <p>Preservation: Both premaxillae are preserved in BMNH R16370, being complete and visible on all surfaces.</p> <p>Contacts: The premaxilla in Azabbaremys contacts the maxilla posterolaterally, the vomer posteriorly, and the other premaxilla medially, as in the other Taphrosphyini.</p> <p>Structures on dorsal surface: The dorsal surface of the premaxilla in Azabbaremys forms the ventral margin of the apertura narium externa and the floor of the fossa nasalis. The apertura has paired grooves at the front that lead posteriorly into the shallow choanal channels that run posterolaterally from the fossa nasalis. Within the fossa the premaxillae on the midline are nearly flat anteriorly, but they rise dorsally very quickly to form a high, median projection dividing the choanal channels and meeting the vomer.</p> <p>Structures on ventral surface: The premaxilla in Azabbaremys forms a deep, acute labial ridge with a median ventral process forming a short hook. On the anterior surface this hook is continuous with a low ridge running on the midline dorsally to the ventral margin of the apertura narium externa. The ridge is unpaired, but at the ventral margin of the apertura, on either side of this ridge, are paired troughs that cut into the lower margin of the apertura narium externa. This premaxillary morphology is unique in turtles. The labial ridge on the premaxilla of Azabbaremys is relatively deep, in contrast to the shallower labial ridge in Nigeremys. Nigeremys also has a very wide and thick labial ridge with a blunt margin. In Azabbaremys and Taphrosphys the ridges are much thinner and more acute. The premaxillae are missing in Arenila.</p> <p>The premaxillae in Azabbaremys form a relatively deep concavity on the midline just posterior to the labial ridge. Nigeremys also has a midline concavity that is hemispherical rather than triangular as in Azabbaremys. The posterior margins of the premaxillae enter the apertura narium interna in Azabbaremys, but they are excluded from it in Nigeremys and Arenila by a vomer-maxilla contact.</p> <p>MAXILLA (figs. 212–216, 280A)</p> <p>Preservation: Both maxillae are complete and visible on all surfaces in BMNH R16370.</p> <p>Contacts of vertical plate: The maxilla in Azabbaremys in lateral view shows a relatively flat, deep, bladelike bone, forming most of the labial ridge, the ventral part of the fossa orbitalis, and the lateral part of the fossa nasalis. The prefrontal and premaxilla contacts are clear on both sides. The maxilla has a long, roughly horizontal suture, with the jugal behind the orbit. In more typical bothremydids such as Bothremys and Rosasia, the jugal contact is not as long.</p> <p>In Azabbaremys the posterior end of the maxilla contacts the quadrate, as in the other Taphrosphyini and most of the Bothremydini. The maxilla-quadrate contact in Azabbaremys is broken slightly on both sides. On the right side it is slightly broken but not displaced. The suture on the external surface can be seen ventrally, beginning in a broken part of the cheek margin and extending dorsally into an area of some breakage with a slight amount of breakage in the sutural contact itself until it reaches the jugal. On the internal surface of the right side, the maxilla-quadrate suture is less disturbed and is altered only by a slight amount of overlap between the two bones. The left side is damaged by anterior-posterior pressure forcing the maxilla and quadrate past each other so that they overlap for about a centimeter. The break did not occur precisely in the suture between the two bones, and part of the maxilla-quadrate suture is clearly visible on the internal surface running dorsally from the ventral margin of the cheek.</p> <p>Structures of vertical plate: The maxilla in Azabbaremys is completely smooth on its external surface; there are no nutrient foramina, as in most other turtles, and there is no ridge or bone texture change indicating the position of the horny rhamphotheca. The dorsal process is wider in Azabbaremys than it is in Phosphatochelys and Taphrosphys; it is about the same as in Nigeremys and Arenila. The labial ridge has an acute edge and curves convex ventrally. The ridge is thinner than in Phosphatochelys, but thicker than in Labrostochelys and Taphrosphys.</p> <p>Contacts of horizontal plate: The maxilla in Azabbaremys contacts the premaxilla anteromedially, the palatine posteromedially, and the jugal posterolaterally. There is no vomer contact as in Labrostochelys, Nigeremys, and Arenila.</p> <p>Structures of horizontal plate: The horizontal plate of the maxilla makes up the triturating surfaces, the floor of the fossa orbitalis, and the floor of the fossa nasalis. The fossa nasalis in Azabbaremys is a large chamber divided posteriorly into paired choanal channels leading into the apertura narium interna. The floor of the fossa orbitalis in Azabbaremys lies above the choanal channel and is angled anterodorsally, forming part of the arched palate seen in Azabbaremys. Only a small part of the orbital floor is actually made up of maxilla; most of it is palatine and jugal.</p> <p>The maxilla bears most of the triturating surface in Azabbaremys. It is roughly parallel-sided; the labial ridge is equidistant from the lingual margin, bordering the apertura narium interna throughout its length. There is a very small contribution of the palatine to the triturating surface posteromedially. The width of the triturating surface in Azabbaremys is narrower than in Nigeremys and Arenila, particularly anteriorly but comparable to Phosphatochelys. In Nigeremys and Arenila the maxilla is broad enough to contact the vomer and prevent narial exposure of the premaxilla. In Azabbaremys the maxilla does not contact the vomer and the premaxilla does enter the apertura narium interna. It is likely that in Taphrosphys the maxilla does not contact the vomer either. The triturating surface in Azabbaremys is unusual in being very rugose and formed by a series of rough corrugations with the shape of small teeth.</p> <p>VOMER (figs. 212–216)</p> <p>Preservation: The vomer was originally complete and well preserved in BMNH R16370. It may have been broken off and lost by the senior author during a misguided cleaning attempt. However, after heroic efforts by the BMNH Curator of Plumbing, it was not found down the drain. Fortunately, the cast of the skull preserves the vomer’s original shape and position, and a series of photos in the AMNH archives also record its morphology (fig. 216).</p> <p>Contacts: The vomer in Azabbaremys contacts only the premaxillae anteriorly. The posterior contact with the palatines figured in Gaffney, Moody, and Walker (2001: figs. 2B, 3) is in error. It is possible but unlikely that such a contact was been eroded away by postmortem damage, but as preserved (fig. 216), there is only the premaxillae contact.</p> <p>Structures: The vomer in Azabbaremys is a thin, curved element, extending dorsally and posteriorly from a high midline process formed by the premaxillae. The vomer shows that the palate in Azabbaremys was highly arched. The dorsal margin of the vomer has a narrow groove in it, the sulcus vomeri of cryptodires that bears the septum nasalis (Gaffney, 1979a: 92). In Labrostochelys, Nigeremys, and Arenila the vomer is dumbbell-shaped in contrast to the thin columnar shape in Azabbaremys. In Arenila and Nigeremys the vomer is also unusually thick and robust. As preserved, the vomer in Azabbaremys is only attached anteriorly to the premaxillae. It tapers posteriorly and there is a gap between the posterior end of the vomer and the palatines. The palatines have an anterior margin that is thin and lacks an expanded area for the reception of the vomer. The anterior margin of the palatines and the posterior margin of the vomer are not finished edges, and a palatine contact could have existed.</p> <p>PALATINE (figs. 212–215, 280A)</p> <p>Preservation: Both palatines are preserved in BMNH R16370, but their posterolateral contacts are slightly damaged and not completely clear. All of the ventral surfaces are visible, but only some of the dorsal surfaces can be clearly determined.</p> <p>Contacts: The palatine in Azabbaremys contacts the maxilla anterolaterally, the other palatine medially, the pterygoid posteriorly, and the jugal laterally. Despite the published figures (Gaffney, Moody, and Walker, 2001: figs. 2B, 3) a vomer contact is not present as preserved. In the floor of the fossa orbitalis, the palatine contacts the maxilla anterolaterally and the jugal laterally. There is no postorbital contact, because the septum orbitotemporale is absent in Azabbaremys.</p> <p>Structures on dorsal surface: The lateral portion of the dorsal surface of the palatine in Azabbaremys is complex and helps form a unique morphology. The absence of the septum orbitotemporale (see Postorbital, Jugal) considerably alters the usual pleurodire morphology in Azabbaremys. The palatine forms most of a ridge that extends between the inside of the cheek laterally and the base of the processus trochlearis pterygoidei medially. This ridge is really the ventral remnant of the septum orbitotemporale. The medial process of the jugal does not extend far enough medially to reach the pterygoid, as in most other pleurodires. Instead, the palatine is widely exposed in the posterior face of the septum orbitotemporale between the jugal and the pterygoid. The palatine forms most of the floor of the orbit. This area is preserved and visible on both sides of Azabbaremys, but the right side is damaged along the lateral palatine suture, and the left side is intact.</p> <p>The palatine in the orbital floor of Azabbaremys is not a flat element. It is high medially and posteriorly. It slopes ventrally, forming a concavity deepest at the jugal and maxilla sutures. Posteromedially the palatine forms a dorsal process, unknown in any other pleurodire, just anterior to the contact of the pterygoid at the base of the processus trochlearis pterygoidei. This process marks the anterolateral limit of the sulcus palatinopterygoideus, a structure that in Azabbaremys lacks the firm base seen in other pleurodires, due to the absence of the septum orbitotemporale.</p> <p>Structures on ventral surface: Only a small part of the palatine enters the triturating surface in Azabbaremys, about the same as in Arenila and Nigeremys. The palatine extends from a free edge anteriorly, the margin of the apertura narium interna (actually the ill-defined foramen orbitonasale), to the posterior free edge on the margin of the fossa temporalis. In nearly all other pleurodires (except some other Taphrosphyini) there is a septum orbitotemporale rather than a free margin posteriorly. Laterally the palatine contacts a short process of the jugal posterolaterally and a short process of the maxilla anterolaterally. Medially the palatine reaches the other palatine. The palatine and descending process of the prefrontal do not meet in the anteroventral part of the orbital floor; they are separated by the maxilla.</p> <p>QUADRATE (figs. 212–216, 218, 281C, 286A)</p> <p>Preservation: Both quadrates are present and well preserved in BMNH R16370.</p> <p>Contacts on lateral surface: In lateral view the quadrate in Azabbaremys contacts the maxilla anteroventrally, the jugal anterodorsally, the quadratojugal dorsally, and the squamosal posterodorsally.</p> <p>Structures on lateral surface: The cavum tympani in Azabbaremys has a completely enclosed incisura columellae auris, as in Nigeremys and Arenila. The cavum tympani is nearly circular, with a distinct notch in its posteroventral edge, presumably for the eustachian tube. The incisura columellae auris in Azabbaremys is a small round hole for the stapes. On the right side of the skull a remnant of the stapes is present. The cavum tympani in Azabbaremys is completely smooth in the area of the antrum postoticum. Neither Arenila nor Nigeremys has an antrum postoticum. Remaining Taphrosphyini do have an antrum postoticum.</p> <p>The quadrate of Azabbaremys has a step or shelf at the ventral margin of the cavum tympani, just above the flat, vertical sheet forming the ventral margin of the quadrate. This shelf (fig. 286A) seems to be in Nigeremys also, although the area is not well preserved. It is indeterminate in Arenila. The quadrate ventral margin is a continuation of the ventral margin of the maxilla, resulting in a lateral profile for Azabbaremys that completely lacks any suggestion of a cheek emargination. Nigeremys has a shallow notch, possibly due to postmortem damage, in the cheek area. Arenila is missing bone in this region.</p> <p>Contacts on dorsal and anterior surface: The quadrate in Azabbaremys contacts the prootic anteromedially, the opisthotic posteromedially, and the squamosal posteriorly. There is no supraoccipital contact, consistent with other Taphrosphyini, but in contrast to most other Bothremydidae.</p> <p>Structures on dorsal and anterior surface: On the anterior face of the otic chamber the quadrate-pterygoid suture is visible on both sides but is best seen on the right. As in other turtles, the quadrate forms the lateral margin of the foramen stapedio-temporalis. The margins of the foramen are eroded on both sides of Azabbaremys, but it is best preserved on the left side. The canalis stapedio-temporalis is free of matrix on the right side, so that the aditus canalis stapedio-temporalis can be clearly seen, as can the foramen and canalis. As in other bothremydids, the foramen stapedio-temporalis in Azabbaremys opens on the anterior face of the otic chamber, not more dorsally as in other pleurodires. The quadrate forms the ventral margin of the foramen stapedio-temporale and the ventral and anterior portions of the canalis cavernosus as it extends medially from the region just beneath the canalis stapedio-temporalis.</p> <p>In Azabbaremys the region between the foramen stapedio-temporale and the processus inferior parietalis is eroded and missing some of the thin bone that covers the canalis cavernosus and forms the margins of the foramen nervi trigemini. The ventral portion of the more lateral part of this area is formed by the quadrate.</p> <p>Contacts on ventral surface: In ventral view the quadrate of Azabbaremys forms part of the very low but distinct tuberculum basioccipitale with the basioccipital. The paired tuberculum is essentially absent in Nigeremys and, apparently, in Arenila. The quadrate has a very narrow contact with the basisphenoid between the broader contacts with the basioccipital and pterygoid. The quadrate contacts the quadrate ramus of the pterygoid in a suture extending from the basisphenoid along the processus articularis of the quadrate, as in other pleurodires.</p> <p>Structures on ventral surface: The foramen posterius canalis carotici interni in Azabbaremys is similar in position to that in Phosphatochelys, in contrast to the pterygoidbasisphenoid-quadrate position of Taphrosphys and the quadrate-only position in Labrostochelys. The foramen posterius canalis carotici interni (see Pterygoid) is formed almost entirely by the pterygoid and quadrate, with a very narrow extension of basisphenoid exposed in the roof and margin of the foramen. Although it is arguable, character 74, position of the foramen posterius canalis carotici interni, has been coded as formed by the pterygoid-quadrate for Azabbaremys, even though the basisphenoid does enter the margin very narrowly.</p> <p>The condylus mandibularis in Azabbaremys lies anterior to the condylus occipitalis, as in Phosphatochelys, but not as far anterior as in Taphrosphys. The fossa pterygoidea is absent in Azabbaremys; there is only a low ridge marking the attachment margin of the pterygoideus muscle.</p> <p>Contacts and structures on posterior surface: Posteriorly in Azabbaremys the cone-shaped squamosal fits onto the posterodorsal part of the quadrate. The medial part of the quadrate meets the other braincase elements and forms structures enclosing the associated soft parts (fig. 218). The quadrate and opisthotic combine to form the ovoid fenestra postotica containing the stapedial artery and lateral head vein. In some forms (such as Taphrosphys) the fenestra is subdivided around those structures, but in Azabbaremys this is not the case. However, the fenestra postotica is widely separated from the foramen jugulare posterius by a well-developed opisthotic-quadrate contact medial to the fenestra postotica. Also, in Nigeremys the fenestra postotica is an ovoid foramen and it is widely separated from the foramen jugulare posterius. In Azabbaremys the quadrate contacts the exoccipital and the basioccipital ventral to the foramen jugulare posterius on the occipital surface.</p> <p>PTERYGOID (figs. 212–215, 218)</p> <p>Preservation: Most of both pterygoids are present in BMNH R16370, but the processus trochlearis pterygoidei is broken on both. On the right side the processus is missing entirely, but on the left side the main body is present but displaced anteriorly. The distal portions of the processus are missing on the left side also. The dorsal structures of the pterygoid are visible but so affected by damage that some areas are missing. Some of the dorsal surface sutures are unclear, although all of the ones on the ventral surface can be seen.</p> <p>Contacts on ventral surface: In ventral view the pterygoid contacts are as in other bothremydids: palatine anteriorly, quadrate posterolaterally, basisphenoid posteromedially, and other pterygoid medially. The palatine contact is not transverse, as in Arenila and Taphrosphys, but is curved and concave anteriorly. The midline pterygoid contact is relatively short compared to Taphrosphys, but Arenila has the pterygoids completely or nearly separated on the midline.</p> <p>Structures on ventral surface: The foramen posterius canalis carotici interni in Azabbaremys lies at the contact of pterygoid and quadrate (see Quadrate) at the posterior edge of the pterygoid. The anterior margin of the foramen is formed by a C-shaped indentation of the pterygoid, while the quadrate and a small extension of the basisphenoid are narrow elongations exposed in the roof and the posterior edge of the foramen. The pterygoid underlies broader exposures of the quadrate and basisphenoid. When compared with the much simpler triple meeting of these three bones in Taphrosphys, it seems as if the pterygoid of Azabbaremys had been dragged posteriorly over the other two bones, pulling the foramen with it.</p> <p>Anterior to the foramen in Azabbaremys is a shallow concavity formed mostly by the pterygoid, with an anteromedial margin that extends right across the pterygoid. This is the scar for the M. pterygoideus, being very shallow in Azabbaremys. In Arenila and Nigeremys this is a concavity, the fossa pterygoidea, much deeper and fully defined, with posteromedial walls completely lacking in Azabbaremys.</p> <p>The processus trochlearis pterygoidei in Azabbaremys is preserved only on the left side and its distal margins are missing. Its base has been broken and the process displaced dorsally and anteriorly. As preserved, the processus is not extensive; it would appear to be similar in shape and extent to that in the living pelomedusids and smaller than in the podocnemidids. The orientation of the processus trochlearis pterygoidei in Azabbaremys is posterolateral, rather than mostly lateral as in many podocnemidids. The Azabbaremys processus differs from Pelomedusidae in having a ridge along its ventrolateral edge, rather than being curved. The processus trochlearis pterygoidei of Nigeremys is present on both sides but badly damaged. Nonetheless, it is consistent with what is known in Azabbaremys.</p> <p>The foramen palatinum posterius is formed in the pterygoid-palatine suture in Azabbaremys, as in most bothremydids. It is preserved only on the left side and faces ventrolaterally rather than ventrally, at least partially as a result of postmortem deformation. However, the arching of the palate in Azabbaremys is somewhat greater than in Nigeremys and Arenila, so that the curve from the palate around the base of the processus trochlearis pterygoidei is more pronounced. Also, the foramen palatinum posterius is located more laterally than in Nigeremys and Arenila, resulting in a foramen that opens more laterally into the fossa temporalis in Azabbaremys than in the others.</p> <p>Contacts on dorsal surface: The anteri- or contacts of the pterygoid at the base of the processus trochlearis pterygoidei in Azabbaremys can be seen on the left side. The pterygoid-palatine contact wraps around the base of the processus from the foramen palatinum posterius dorsally to the edge of the sulcus palatinopterygoideus. The pterygoid is clearly separated from the medial process of the jugal by the palatine. This is an unusual condition; in nearly all pleurodires the jugal contacts the pterygoid in this area. The septum orbitotemporale that is formed by medial processes of the postorbital and jugal in other pleurodires is absent in Azabbaremys and small in all other Taphrosphyini except Arenila and Nigeremys. The enlarged palatine forms the only remaining anterior support for the base of the processus trochlearis pterygoidei in Azabbaremys.</p> <p>Structures on dorsal surface: The dorsal surface of the pterygoid bears the crista pterygoidea and forms the floor of the canalis cavernosus and foramen nervi trigemini. The crista pterygoidea is preserved and visible on both sides in Azabbaremys. It rises above the level of the pterygoid plate and meets the processus inferior parietalis, making up the lower third of the braincase wall (fig. 217). The crista pterygoidea plus processus inferior parietalis are relatively short in comparison with such forms as in Podocnemis. The foramen nervi trigemini has been eroded along its margins as well as the anterior margin of the processus inferior parietalis. However, the damage is not enough to significantly narrow this structure.</p> <p>The bones, prootic plus pterygoid, making up the anterior wall of the canalis cavernosus at the anterior edge of the otic chamber are eroded, opening up the canalis on both sides. Nonetheless, the relative positions of the foramen nervi trigemini and the foramen stapedio-temporale can be determined. These foramina are relatively close to each other, as in other bothremydids.</p> <p>SUPRAOCCIPITAL (figs. 212, 215, 217)</p> <p>Preservation: The supraoccipital is present and nearly complete in BMNH R16370, but only the right side is visible; the left side is still covered with matrix.</p> <p>Contacts: The median section of the supraoccipital underlies the two parietals along the midline. Their mutual contact slopes anteroventrally. The laterally projecting otic portion of the supraoccipital in Azabbaremys contacts the prootic anterolaterally, the opisthotic laterally, and the exoccipital posterolaterally. As in the other Taphrosphyini, there is no supraoccipital-quadrate contact.</p> <p>Structures: The crista supraoccipitalis in Azabbaremys is relatively short, comparable to that in living pelomedusids, but slightly longer than in Taphrosphys. Although incomplete, the crista in Arenila seems to be longer than in Azabbaremys, compared to the position of the condylus occipitalis. The crista supraoccipitalis in Nigeremys is similar in length to Azabbaremys but seems to be incomplete. The crista supraoccipitalis in Azabbaremys is deeper anteriorly and narrows to an acute posterior end. In Taphrosphys the end of the crista is curved and blunt. The very end of the crista is broken off in Azabbaremys, but it is already very narrow and is probably missing only a small section.</p> <p>EXOCCIPITAL (figs. 212, 215, 217, 218)</p> <p>Preservation: Both exoccipitals are preserved in BMNH R16370; they are complete, but only the right one is entirely free of matrix. Both have clear sutures.</p> <p>Contacts: The exoccipital in Azabbaremys contacts the supraoccipital dorsally, the opisthotic laterally, and the basioccipital ventrally and ventrolaterally. There is also a contact with the quadrate ventrolaterally between the basioccipital and opisthotic. This quadrate contact is found in all bothremydids and is absent in all other Pelomedusoides.</p> <p>Structures: The exoccipital in Azabbaremys forms all of the condylus occipitalis; the basioccipital enters the neck of the condyle. The exoccipitals make up the condyle in all of the described bothremydids. However, this cannot be substantiated in either Nigeremys or Arenila due to poor preservation, but Lapparent de Broin and Werner (1998) described both taxa as having this feature. In Azabbaremys the exoccipitals are eroded on the midline, giving the condyle a bilobed appearance. The foramen jugulare posterius is formed almost entirely by the exoccipital, with a narrow section of opisthotic entering the foramen dorsolaterally. The foramen is entirely closed by bone, as in Taphrosphys, Arenila, and Bothremys, in contrast to the open condition in Foxemys. Between the foramen jugulare posterius and the condylus occipitalis are the two foramina nervi hypoglossi.</p> <p>BASIOCCIPITAL (figs. 212–215, 217, 218)</p> <p>Preservation: The basioccipital in BMNH R16370 is complete and clearly defined.</p> <p>Contacts: The basioccipital is a wide but very short, triangular element in Azabbaremys. It makes up the medial half of the tuberculum basioccipitale along with the quadrate laterally. Its entire anterior margin is a transverse contact with the basisphenoid. Posteriorly and dorsally, the basioccipital contacts the exoccipitals, reaching only the base of the condylus occipitalis.</p> <p>Structures: Between the paired tubercula basioccipitale is a shallow median concavity that extends slightly onto the basisphenoid. The basioccipital in Nigeremys is not clearly defined by sutures. This element in Taphrosphys is much larger and longer and is just as wide. Arenila has a longer basioccipital also, and its anterior contact with the basisphenoid is curved and concave posteriorly.</p> <p>PROOTIC (figs. 212, 215)</p> <p>Preservation: Both prootics are present and visible in BMNH R16370, although they are eroded in the area of the canalis cavernosus and the sutures are not always clear.</p> <p>Contacts: The prootic in Azabbaremys contacts the supraoccipital posteromedially, the parietal medially, the pterygoid ventrally, the quadrate laterally, and the opisthotic posterolaterally. The prootic forms the medial margin of the foramen nervi trigemini, the parietal forms the anterodorsal corner, and the pterygoid forms the anterior and ventral margins.</p> <p>Structures: The foramen nervi trigemini as preserved is incomplete on both sides due to erosion of the medial margin exposing the canalis cavernosus. The prootic-pterygoid suture is gone in this area, so its position and the relative amount of prootic versus pterygoid contribution to the margin of the foramen nervi trigemini is not determinable. The foramen stapedio-temporale is formed in the prootic-quadrate suture and opens directly anteriorly as in most bothremydids. Although much of the bone between the foramen stapedio-temporale and the foramen nervi trigemini is eroded away, it can be seen that these structures were relatively close together, as in Taphrosphys and Bothremys.</p> <p>OPISTHOTIC (figs. 212, 215, 218)</p> <p>Preservation: The opisthotic is preserved completely on both sides of BMNH R16370. It is clearly defined and visible except on the dorsal area of the left side where it is covered with matrix.</p> <p>Contacts: The opisthotic in Azabbaremys has the usual contacts for bothremydids: supraoccipital dorsomedially, prootic anteromedially, quadrate anterolaterally, squamosal posterolaterally, quadrate (again) ventrolaterally, and exoccipital posteromedially.</p> <p>Structures: The opisthotic in Azabbaremys forms the roof of the fenestra postotica; the ventral half of the fenestra is formed by the quadrate (fig. 218). The fenestra is an oblong oval, presumably with the stapedial artery lying in the upper part and the lateral head vein in the lower part. The processus interfenestralis of the opisthotic forms the relatively thick lateral wall of the foramen jugulare posterius, contacting the exoccipital ventromedially and the quadrate ventrolaterally. A foramen, probably the foramen externum nervi glossopharyngei, penetrates the middle of the processus interfenestralis. Above this foramen is a much smaller foramen, which could alternatively be interpreted as the foramen nervi glossopharyngei. Neither can be probed, so their identification is in doubt. Neither of these foramina is found in Bothremys.</p> <p>BASISPHENOID (figs. 212–215)</p> <p>Preservation: The basisphenoid is present and clearly defined in BMNH R16370.</p> <p>Contacts and structures on ventral surface: The basisphenoid in Azabbaremys has the triangular shape typical for many bothremydids: wider than long, with a straight transverse posterior suture with the basioccipital, rather than the curved suture seen in Arenila. The lateral contact with the quadrate is relatively narrow. Anterolaterally the basisphenoid very narrowly enters the margin of the foramen posterius canalis carotici interni (see Pterygoid, Quadrate). The anterior contacts of the basisphenoid are with the pterygoids.</p> <p>Contacts and structures on dorsal surface: The dorsal surface of the basisphenoid in Azabbaremys can be seen inside the nearly cleaned out cavum cranii. An endocast has been made to facilitate this study (fig. 217). The dorsum sellae is relatively high, compared to living Pelomedusoides and Bothremys. A well-developed processus clinoideus rises on each side of the dorsum, also in contrast to the lower processus clinoideus of Bothremys and living Pelomedusoides. The dorsum sellae in Azabbaremys does not overhang the sella turcica, also in contrast to the above taxa. The sella turcica is shorter due to the very short rostrum basisphenoidale, in contrast to the longer sella and very long rostrum in Bothremys and the living Pelomedusoides. The rostrum basisphenoidale in Azabbaremys is very short, with a deep concave anterior face. On either side thin walls may represent ossified portions of the trabeculae. The entire dorsal basisphenoid morphology in Azabbaremys is a foreshortened version of that seen in other Pelomedusoides. This is consistent with the ventral morphology, which also shows a foreshortened basisphenoid.</p> <p>SUBTRIBE NIGEREMYDINA</p> <p>Nigeremys gigantea</p> <p>The single skull representing this taxon is nearly complete but has a very badly damaged surface, making sutures difficult or impossible to see. This skull has been described briefly by Bergounioux and Crouzel (1968), but only Lapparent de Broin and Werner (1998) actually have a useful description. Nigeremys is the sister taxon to the similar Arenila, together making up the Nigeremydina, which is the sister taxon to the Taphrosphyina.</p> <p>PREFRONTAL (figs. 219, 222)</p> <p>Preservation: Both prefrontals are present in MNHN (P) NIR 1, in which the surface is damaged by erosion and pitting, but little bone has been lost, and the marrow cavity is not exposed. The original shapes of the bones seem intact. Sutures are clear but are partially obscured by being drawn over in ink.</p> <p>Contacts: The usual bothremydid contacts are present in Nigeremys: frontal posteriorly, maxilla anteroventrolaterally, and prefrontal medially. The contacts are similar to those in Azabbaremys, except that the prefrontal-maxilla contact is more dorsal in Nigeremys than in Azabbaremys. Only the posterior part of the prefrontal is present in Arenila and it agrees with Nigeremys.</p> <p>Structures: The prefrontal forms a protruding dorsal margin for the apertura narium externa in Nigeremys, which is shaped like that in Azabbaremys. In Nigeremys the prefrontal does not extend over the premaxilla in dorsal view as it does in Azabbaremys. The prefrontal forms the anterior wall of the fossa orbitalis, but Nigeremys has less of the bone exposed in the orbital margin than in Arenila and Azabbaremys. The prefrontal exposure in the fossa orbitalis is obscured by matrix and breakage in both orbits of Nigeremys.</p> <p>Although Bergounioux and Crouzel (1968) described paired nasal bones in ‘‘ Potamochelys ’’, neither Lapparent de Broin and Werner (1998) nor we have found any evidence for their presence in MNHN (P) NIR 1.</p> <p>FRONTAL (figs. 219, 222)</p> <p>Preservation: Both frontals are present in MNHN (P) NIR 1, in which the surface is damaged by erosion and pitting, but little bone has been lost. There is no evidence of deformation. Most of the sutures are clear but partially obscured by being drawn over in ink. The postorbital contacts are damaged enough to make their exact position unclear, but enough is preserved to show that there is a postorbital contact.</p> <p>Contacts: Nigeremys has the usual bothremydid contacts: prefrontal anteriorly, postorbital posterolaterally, parietal posteriorly, and other frontal medially. There is no prefrontal-postorbital contact preventing frontal exposure in the orbit, as shown in Bergounioux and Crouzel (1968: fig. 1). The frontal-parietal suture is straight, not curved. The frontal-prefrontal suture does not protrude anteriorly on the midline as much in Nigeremys as it does in Arenila, and its midline length is slightly less in Nigeremys than in Arenila.</p> <p>Structures: The frontal forms the dorsal part of the orbital margin in Nigeremys, as in Arenila. The internal surface is covered by matrix.</p> <p>PARIETAL (figs. 219, 222)</p> <p>Preservation: Both parietals are present in MNHN (P) NIR 1, in which the surface is damaged by erosion and pitting. The posterior margin of the left parietal appears intact, but some bone is broken from the right parietal. The processus inferior parietalis is not visible due to matrix. The sutures are clear.</p> <p>Contacts of dorsal plate: As in other bothremydids, the parietal of Nigeremys contacts the frontal anteriorly, the postorbital laterally, and the other parietal medially. The possibility of a posterolateral contact with the quadratojugal as in Taphrosphys and Phosphatochelys cannot be ruled out. The contact with the supraoccipital is at the posteromedial margin of the parietal.</p> <p>Structures of dorsal plate: The posterior temporal emargination in Nigeremys completely exposes the otic chamber and is more emarginate than in Azabbaremys, Phosphatochelys, and Taphrosphys. The margin on the parietal is straight, as in Azabbaremys. Arenila could have had a very similar emargination to Nigeremys, but it is missing much of the edge.</p> <p>Contacts and structures of processus inferior parietalis: The parietal in Nigeremys overlies the supraoccipital posteriorly, but the suture is unclear and none of the processus inferior parietalis is exposed.</p> <p>JUGAL (figs. 219, 222)</p> <p>Preservation: The area of the jugal is badly damaged with no clear sutures in MNHN (P) NIR 1. The anterior part of the jugal-postorbital contact and the jugal-maxilla contact can be seen, but we are unable to confirm the jugal contacts of either Bergounioux and Crouzel (1968) or Lapparent de Broin and Werner (1998). The latter authors showed a large jugal extending from the orbital margin to the temporal emargination, a condition unknown in any other pleurodire. This area is badly damaged by cracking and overpreparation, with a number of cracks expanded by overzealous incising of presumed sutures. Nonetheless, careful examination of the supposed jugal sutures of Lapparent de Broin and Werner (1998) has failed to corroborate them. The posterior limits of the jugal in Nigeremys are not determinable in our interpretation.</p> <p>Contacts of the lateral plate: On both sides of MNHN (P) NIR 1, just below the orbital margin, is a contact with the maxilla. On the right side, more dorsally in the orbital margin, is the postorbital contact. Both of these become indistinguishable posteriorly. These sutures in Nigeremys are in about the same position in Arenila and in Azabbaremys.</p> <p>Structures of the lateral plate: The jugal in Nigeremys enters the orbital margin; whether it entered the cheek margin is unknown.</p> <p>Contacts and structures of the medial process: We have been unable to identify sutures for the medial process of the jugal in MNHN (P) NIR 1, although the area is preserved in the lower temporal fossa on both sides. Lapparent de Broin and Werner (1998) did not identify any jugal in ventral view.</p> <p>QUADRATOJUGAL</p> <p>Preservation: Although both Bergounioux and Crouzel (1968) and Lapparent de Broin and Werner (1998) identified a quadratojugal in MNHN (P) NIR 1, we have been unable to confirm any sutures defining this element. The cheek area where Lapparent de Broin and Werner (1998) showed quadratojugal sutures certainly has deeply incised fissures in these positions. However, microscopic examination of these cracks has revealed only broken bone fragments and glue, and they have the appearance of mechanical abrasion. It is possible that some of these fissures represent natural sutures, but this cannot be corroborated by us. It is possible that a maxilla-quadrate contact was present on the cheek in Nigeremys, and that the quadratojugal was placed dorsally, as in Azabbaremys.</p> <p>SQUAMOSAL (figs. 219, 222)</p> <p>Preservation: Both squamosals are present in MNHN (P) NIR 1, but the surfaces are damaged and only a few sutures are visible. The posterior surface is eroded and little if any of the original surface is preserved.</p> <p>Contacts: As in other bothremydids, the squamosal of Nigeremys contacts the quadrate anteriorly and the opisthotic medially. The quadratojugal contact is not distinguishable.</p> <p>Structures: The squamosal of Nigeremys is not well preserved, but it is similar in size and position to the squamosal in Azabbaremys. There is no ventral flange as in Taphrosphys. The squamosal in Arenila is poorly preserved also, but it seems to be longer than the one in Nigeremys.</p> <p>POSTORBITAL (figs. 219, 222)</p> <p>Preservation: The postorbital is present on both sides of MNHN (P) NIR 1, but its defining sutures are obscured by poor preservation and overpreparation. The parietalpostorbital suture and the anterior part of the jugal-postorbital are clear, but the more posterolateral sutures are ambiguous.</p> <p>Structures: The postorbital of Nigeremys seems to extend posteriorly to reach the posterior temporal emargination, as in Azabbaremys and in contrast to Phosphatochelys. However, the bone is too poorly preserved to be sure that the quadratojugal did not contact the parietal. Lapparent de Broin and Werner (1998: fig. 4f) showed an elongate postorbital with a parasagittal jugal suture. We have been unable to confirm this suture.</p> <p>PREMAXILLA (figs. 219–222)</p> <p>Preservation: Both premaxillae are present in MNHN (P) NIR 1, but the sutures are unclear and are determinable only near the labial ridge. The bone surface is eroded and pitted, but it seems to be close in shape to the original bone. The dorsal end of the dorsal process is broken in both, and there is a hole in the midline concavity on the triturating surface.</p> <p>Contacts: As in other bothremydids the premaxilla contacts in Nigeremys are with the vomer posteriorly, the maxilla posterolaterally (visible only on the labial ridge and near the vomer on the left side), and with the other premaxilla on the midline (visible only in a few places). As in Arenila, Nigeremys has an unusually long premaxilla, so the midline premaxilla contact and the posterolateral maxilla contact are unusually long.</p> <p>Structures in dorsal view: Very little of the dorsal surface of the premaxilla is visible in MNHN (P) NIR 1 due to matrix and breakage. The midline dorsal process can be seen, and it is large and broad, as in Arenila but in contrast to other Taphrosphyini. The dorsal end of the process is broken off.</p> <p>Structures in ventral view: The labial ridge on the premaxilla in Nigeremys is very thick, as in Azabbaremys. However, in Nigeremys the ridge is blunt in contrast to acute in Azabbaremys. It is possible that this is due to weathering, but the relatively even nature of the ridge suggests it is naturally blunt even though very little original bone surface is present. Azabbaremys has a very shallow, parasagittal groove extending vertically on the anterior face of the premaxilla (see Azabbaremys, Premaxilla); this groove is absent in Nigeremys. The anterior face of the premaxilla in Nigeremys is not as deep as in Azabbaremys.</p> <p>The midline concavity formed by the premaxilla is very deep in Nigeremys, as it is in Arenila but in contrast to all other Taphrosphyini. As described by Lapparent de Broin and Werner (1998), the foramen praepalatinum is formed entirely by the premaxilla, as in Arenila and the other Taphrosphyini in which it is determinable.</p> <p>MAXILLA (figs. 219–222)</p> <p>Preservation: Both maxillae are present and nearly complete, but as with the other bones in MNHN (P) NIR 1, the maxilla surfaces are badly damaged by erosion and pitting, at least partly the result of overpreparation. The sutures are not clear, and we have not been able to confirm many of the contacts described in Lapparent de Broin and Werner (1998) (see below).</p> <p>Contacts of vertical plate: In MNHN (P) NIR 1 the prefrontal contact is visible on both sides and the anterior part of the jugal suture. However, microscopic examination of the cheek does not confirm the jugal and quadratojugal contacts figured by Lapparent de Broin and Werner (1998: fig. 4f). There are grooves and fissures, but these seem to be natural cracks enlarged mechanically. It is quite possible that the quadratojugal did not contact the maxilla, and that there was a maxilla-quadrate contact, as in Azabbaremys and other Taphrosphyini.</p> <p>Structures of vertical plate: The dorsal process of the maxilla in Nigeremys differs from Arenila and Azabbaremys in having a prefrontal contact that is inclined anteroventrally rather than posteroventrally, but the thickness of the process is similar in all three, and in Azabbaremys the maxilla forms the lateral margin of an apertura narium externa that is about as wide as it is in Arenila and narrower than in Azabbaremys.</p> <p>The suborbital depth of the maxilla in Nigeremys is greater than in Arenila, but it is about the same as in Azabbaremys. Arenila has possibly been made shallower by damage (see Arenila, Maxilla). There is a slight emargination along the cheek margin in Nigeremys on the left side, and most of the right cheek margin is missing. This cheek emargination seems to have a broken edge, so it probably is not original.</p> <p>Contacts of the horizontal plate: The premaxilla suture in Nigeremys is visible in a few places (see Premaxilla) and the vomer suture can be seen for both maxilla. Arenila also has a vomer-maxilla contact via a short median process of the maxilla, and both are absent in Azabbaremys. These sutures and the palatine sutures have been described and figured by Lapparent de Broin and Werner (1998: fig. 4b) and we can confirm them. The jugal suture, presumably exposed in the fossa temporalis inferior wall, is not discernable.</p> <p>Structures of the horizontal plate: The triturating surface in Nigeremys has a very thick, blunt labial ridge as described and figured in Lapparent de Broin and Werner (1998) and Bergounioux and Crouzel (1968). This agrees with the very thick labial ridge of Arenila. Azabbaremys is also thick in comparison to other Taphrosphyini, but not as thick as in Nigeremys and Arenila. Nigeremys has a blunt margin, possibly due to postmortem erosion (see Premaxilla), in contrast to the acute edge seen in Arenila and Azabbaremys. The triturating surfaces of Nigeremys and Arenila are wider anteriorly due to a narrow medial process reaching the vomer. In both a low, thick lingual ridge is separated from the much higher labial ridge by a shallow trough. Lingual and labial ridges are parallel. Lapparent de Broin and Werner (1998) stated that the maxillary triturating surfaces are wider in Arenila than in Nigeremys, but our own measurements of the triturating surface at the position of the apertura narium interna (appendix 5) divided by the total length (partially restored for Arenila) results in a ratio of 4.0 for Arenila and 3.8 for Nigeremys, suggesting that they are both nearly the same.</p> <p>The apertura narium interna in Nigeremys is very similar in size and position to that in Arenila. The apertura is more triangular in Azabbaremys and oval in Nigeremys.</p> <p>VOMER (figs. 219–222)</p> <p>Preservation: The vomer in MNHN (P) NIR 1 is nearly complete, but with the usual surface damage seen in this specimen. The sutures are relatively clear except on the right anterior edge where there is some breakage.</p> <p>Contacts: Nigeremys has the vomer contacts seen in Arenila: premaxilla anteriorly, maxilla anterolaterally, and palatine posteriorly.</p> <p>Structures: As in Arenila, the vomer of Nigeremys is unusually thick and wide, in contrast to Azabbaremys and Labrostochelys, the only other Taphrosphyini in which it is known. Palatal arching is much less in Nigeremys and Arenila than in Azabbaremys (see Arenila, Vomer). The apertura narium interna of Nigeremys is about the same size as in Arenila (see Arenila, Vomer).</p> <p>PALATINE (figs. 219–222)</p> <p>Preservation: Both palatines are present in MNHN (P) NIR 1, but they are damaged by surface erosion and pitting. The anterolateral sutures are clear, but the posterior and lateral ones are not. No dorsal surface morphology is visible due to matrix.</p> <p>Contacts: Palatine sutures in MNHN (P) NIR 1 are not clear despite the description and figure in Lapparent de Broin and Werner (1998: fig. 4b), but we have no reason to contradict these. There is an anterolateral one with the maxilla, and, on the right side, a posterior one with the pterygoid. No sutures are visible on the dorsal surface. The midline suture is not clear.</p> <p>Structures on ventral surface: The palatine in Nigeremys contributes only a small part to the triturating surface, as in Arenila and Azabbaremys. The choanal passage is a large, curved trough on each palatine, confluent with the apertura narium interna. The choanal passage of Nigeremys is almost the same as in Arenila, and both have a low midline ridge absent in Azabbaremys. The foramen palatinum posterius in Nigeremys seems to be completely formed by the palatine, but this is not certain due to unclear sutures. The foramen lies at the top of a cone-shaped concavity, very similar to the one seen in Arenila and distinct from the flat surface of Azabbaremys.</p> <p>QUADRATE (figs. 219–223)</p> <p>Preservation: Both quadrates are present in MNHN (P) NIR 1, but the bone is poorly preserved and has been further damaged by overpreparation, ink lines, and glue. The left quadrate is more complete than the right one. It is crushed slightly dorsoventrally and part of the cavum tympani is broken away. The bone surface is eroded and pitted and sutures are unclear. The right quadrate is badly crushed dorsoventrally so that the cavum tympani is barely discernable and the sulcus eustachii is not discernable. The processus articularis is broken off the right side. Although Lapparent de Broin and Werner (1998: fig. 4b, f) described sutures for the quadrate, we have been unable to confirm them.</p> <p>Contacts in lateral view: The cheek on both sides in MNHN (P) NIR 1 is badly damaged and poorly preserved. We have been unable to confirm the sutures figured by Lapparent de Broin and Werner (1998: fig. 4f) showing a large quadratojugal contacting the quadrate anteriorly. There are cracks and fissures, as well as ink lines, in this area, but a careful microscopic examination has failed to distinguish sutures. However, it is quite possible to find fissures and cracks consistent with a quadrate-maxilla contact, as seen in Azabbaremys. We also dispute the quadrate-squamosal suture drawn by Lapparent de Broin and Werner (1998: fig. 4f). This is a crack that extends ventromedially into the cavum tympani and is not a suture.</p> <p>Structures in lateral view: The cavum tympani in Nigeremys, visible on the left side, is unusually deep and overhung by its margins. This is probably due to dorsoventral crushing that has made the cavum lower and more oval than it was originally. It is quite possible that the cavum tympani in Nigeremys was originally similar in size and shape to that in Azabbaremys, that is, nearly circular. The incisura columellae auris in Nigeremys is completely closed, as in Arenila. The sulcus eustachii is a narrow, clearly defined trough, also similar to that in Azabbaremys. There is no sign of an antrum postoticum in Nigeremys, although the poor preservation does not preclude the presence of a small one. The antrum is absent in Azabbaremys also. As in most bothremydids, the fossa precolumellaris is absent in Nigeremys. Nigeremys has a well-developed shelf below the cavum tympani as in Azabbaremys.</p> <p>Contacts in dorsal view: Sutures on the dorsal surface of the otic chamber in MNHN (P) NIR 1 are not distinguishable.</p> <p>Structures in dorsal view: The foramen stapedio-temporale in MNHN (P) NIR 1 is not determinable.</p> <p>Contacts in ventral and posterior views: Although Lapparent de Broin and Werner (1998: fig. 4f) showed a number of quadrate sutures in MNHN (P) NIR 1, we have only been able to confirm the basioccipital-quadrate suture. This lies about halfway along the ridge forming the posterior wall of the fossa pterygoidea. The Lapparent de Broin and Werner (1998) figure shows this suture placed more anteromedially, as a function of a very narrow basioccipital. We interpret the basioccipital as wider (see Basioccipital) and place the quadrate suture more laterally, as in Arenila.</p> <p>Structures in ventral and posterior views: The foramen posterius canalis carotici interni in Nigeremys was figured by Lapparent de Broin and Werner (1998: fig. 4f) as being in the roof of the fossa pterygoidea and formed by the quadrate and pterygoid (left side) and quadrate, pterygoid, and basisphenoid (right side). We have carefully examined this area in MNHN (P) NIR 1 and have been unable to confirm the position or presence of this foramen. The two areas indicated in Lapparent de Broin and Werner (1998) are badly eroded and pitted, with a few pits more heavily prepared than others. We see no sign of natural foramina margins or sutures.</p> <p>Although not identified in a figure Lapparent de Broin and Werner (1998: 179) described the ‘‘facial foramen’’ (i.e., the foramen nervi facialis). However, we have been unable to confirm the presence of this foramen. The fossa pterygoidea is probably formed mostly by quadrate and pterygoid in Nigeremys. The fossa is relatively deep and large, as in Arenila but in strong contrast to all the other Taphrosphyini, which lack it.</p> <p>The condylus mandibularis and processus articularis are present on the left side of MNHN (P) NIR 1, but the bone surface is damaged. The right quadrate lacks the condylus and most of the processus articularis. The condylus mandibularis in Nigeremys lies at about the level of the condylus occipitalis, as it does in Arenila, but in contrast to the more anterior position in Azabbaremys and the other Taphrosphyini. The occipital structures are badly preserved, but the fenestra postotica (fig. 223) is discernable and seems to consist of a single opening, although markings drawn on the specimen obscure some features.</p> <p>PTERYGOID (figs. 219–222)</p> <p>Preservation: Both pterygoids in MNHN (P) NIR 1 are present and nearly complete, but their surfaces are pitted and eroded. Sutures are unclear. Breakage is present along the margins, particularly the processus trochlearis pterygoidei and the quadrate ramus. Only the ventral surface is visible.</p> <p>Contacts on ventral surface: Only a few sutures are discernable in MNHN (P) NIR 1. We agree with Lapparent de Broin and Werner (1998: fig. 4f) in the position of the anterior palatine-pterygoid suture, the midline suture, and the general position of the basisphenoid suture. However, the basisphenoid is slightly more anterior in our interpretation, resulting in a very narrow midline contact of the two pterygoids, similar to that in Arenila. We are unable to confirm the pterygoid-quadrate suture figured by Lapparent de Broin and Werner (1998: fig. 4f).</p> <p>Structures on ventral surface: The processus trochlearis pterygoidei in Nigeremys trends posterolaterally, as in Arenila and Phosphatochelys. It is eroded around its margins (on both sides) but seems to be in its original position and to retain its original size. The quadrate ramus is a high wall forming the posterior margin for the fossa pterygoidea, as in Arenila. The fossa pterygoidea (see Quadrate) seems to be formed by the quadrate posteriorly, the pterygoid anteriorly, and the basisphenoid medially, as in Arenila. The foramen posterius canalis carotici interni is not identifiable (see Quadrate).</p> <p>Contacts and structures on dorsal surface: The right fossa temporalis in MNHN (P) NIR 1 still contains matrix, but the left one shows the lateral surface of the processus trochlearis pterygoidei and some of the postorbital wall. Sutures are not discernable. Enough of the sulcus palatinopterygoideus can be made out to show that it is narrow, not wide as in Azabbaremys.</p> <p>SUPRAOCCIPITAL (figs. 219, 222, 223)</p> <p>Preservation: The supraoccipital in MNHN (P) NIR 1 is covered by matrix anteriorly, and much of the crista supraoccipitalis is missing. The bone is poorly preserved and badly pitted.</p> <p>Contacts: No sutures are visible in MNHN (P) NIR 1.</p> <p>Structures: The crista supraoccipitalis in Nigeremys can be seen in cross section, and the lower part is much thicker than the upper part, as in Arenila. The crista is broken posteriorly, so its length cannot be determined, but its longest part is at the ventral edge, which is longer than the ventral edge in Azabbaremys. The edges of the foramen magnum are not clear, as it is filled with matrix.</p> <p>EXOCCIPITAL (figs. 219, 222, 223)</p> <p>Preservation: Both exoccipitals are present in MNHN (P) NIR 1, but despite their bone surfaces being better preserved than most of the skull, sutures are not discernable.</p> <p>Contacts: No sutures are visible in MNHN (P) NIR 1.</p> <p>Structures: The edges of the foramen magnum in Nigeremys are not clear due to matrix. The bones making up the condylus occipitalis cannot be determined. Lapparent de Broin and Werner (1998: fig. 4f) showed a large basioccipital entering the condyle. However, it is just as likely that it was formed solely by exoccipitals. One foramen nervi hypoglossi could be interpreted on the right side of Nigeremys. The foramen jugulare posterius (fig. 223) is more certain, despite markings drawn on the specimen. The foramen is closed laterally and is separated from the fenestra postotica by a distance about the same as in Arenila and farther than in Azabbaremys.</p> <p>BASIOCCIPITAL (figs. 219–222)</p> <p>Preservation: The basioccipital is present and nearly complete in MNHN (P) NIR 1, but the surface is badly eroded and pitted. Nonetheless, we think that some sutures are discernable.</p> <p>Contacts: Our interpretation of the basioccipital shape in MNHN (P) NIR 1 differs from that in Lapparent de Broin and Werner (1998). They showed an elongate, parallel-sided basioccipital not much thicker than the condylus occipitalis. Microscopic examination does not confirm these as sutures. In our interpretation, on the left anterior margin of the basioccipital is an anterolaterally trending suture paralleling the fossa pterygoidea. This is the basisphenoid contact, and posteriorly it is the basioccipital-quadrate contact. These sutures show that the basioccipital of Nigeremys is wider than long and has posterolateral processes extending along the fossa pterygoidea, all as in Arenila. In any case, the bone surface is poorly preserved, allowing a number of interpretations.</p> <p>Structures: The contribution, if any, of the basioccipital to the condylus occipitalis cannot be determined in MNHN (P) NIR 1 (see Exoccipital). As in Arenila, there is no prominent tuberculum basioccipitale in Nigeremys. We have been unable to find a foramen posterius canalis carotici interni (see Quadrate). There is a shallow concavity on the surface of the basioccipital, as in Arenila. If the question of sutures is put aside, there is remarkably close agreement in the shape of the bone surface in the basicranium in both Nigeremys and Arenila.</p> <p>PROOTIC</p> <p>Preservation: Both prootics are presumably present in MNHN (P) NIR 1, but the absence of sutures and surface damage makes it hard to define them. The right one is still partially obscured by matrix, but the left one is visible.</p> <p>Contacts: No sutures are discernable in MNHN (P) NIR 1.</p> <p>Structures: Neither the foramen nervi trigemini nor the foramen stapedio temporale can be identified with assurance in Nigeremys. However, the dorsal surface of the left otic chamber is better preserved than most of the skull, and it seems likely that a foramen would be visible if present on the dorsal surface. The anterior surface has pits and damaged areas that could be a foramen.</p> <p>OPISTHOTIC (figs. 219–223)</p> <p>Preservation: Both opisthotics are present in MNHN (P) NIR 1, but their posterior surfaces are badly pitted and eroded. Most sutures are not discernable.</p> <p>Contacts: The opisthotic-squamosal suture is visible on both sides in MNHN (P) NIR 1 but other contacts are not, despite the sutures figured in Lapparent de Broin and Werner (1998: fig. 4f).</p> <p>Structures: The fenestra postotica in Nigeremys is a single oval placed laterally far from the foramen jugulare posterius (see Quadrate). The posterior edge of the opisthotic in Nigeremys has a large, horizontal ridge not found in Azabbaremys (the opisthotic is missing in Arenila). The ridge continues onto the squamosal. Some of the ridge may be missing, as the margin has the appearance of a broken edge.</p> <p>BASISPHENOID (figs. 219–222)</p> <p>Preservation: The basisphenoid is complete in MNHN (P) NIR 1, but its surface is damaged by pitting and erosion. Some sutures are discernable on the left side. Only the ventral surface is visible.</p> <p>Contacts: On the ventral surface, the basisphenoid in Nigeremys contacts the pterygoid anterolaterally and the basioccipital posteriorly. Presumably, there is a posterolateral contact with the quadrate.</p> <p>The basisphenoid as figured in Lapparent de Broin and Werner (1998: fig. 4f) is an elongate, parallel-sided element with a transverse basioccipital suture. The sutures we have found show the basisphenoid to be a triangular element, wider than long, with a curved basioccipital suture. The degree to which it enters the fossa pterygoidea is not determinable.</p> <p>Structures on the ventral surface: The foramen posterius canalis carotici interni is not determinable (see Quadrate, Pterygoid). It could have been in the pterygoid-basisphenoid suture and might be one of the many pits and defects in this area. The fossa pterygoidea is probably formed medially by the basisphenoid. The roof of the fossa is particularly damaged with no clear sutures or bone surface.</p> <p>Arenila krebsi</p> <p>Arenila is based on one partial skull from the Maastrichtian of Egypt. Enough of the palate is present to determine most of that area, but the quadrates are poorly preserved. This skull was described by Lapparent de Broin and Werner (1998), who provided good photographs but no line drawings to go with them. To take advantage of those photographs, we provide labeled line drawings for the views in Lapparent de Broin and Werner (1998), as well as our own photographs. Arenila is the sister to Nigeremys, together making up the subtribe Nigeremydina, which is the sister group to the subtribe Taphrosphyina.</p> <p>PREFRONTAL (figs. 224, 227)</p> <p>Preservation: Most of the prefrontal in TUB Vb-641 is preserved on the left side, but it lacks its anterior margin. The right one is completely missing. Despite Lapparent de Broin and Werner’s (1998) assertion, not enough of the prefrontal margin is preserved to show that the apertura narium externa in Arenila is larger than the apertura narium externa in Nigeremys. The sutures are clearly visible, with the bones being slightly displaced along them. The prefrontal is broken by a parasagittal crack running from the frontal suture to the anterior eroded edge of the prefrontal just medial to the midline.</p> <p>Contacts: The preserved contacts in Arenila show the usual ones for Bothremydidae: frontal posteriorly and maxilla anteroventrolaterally. The midline contact with the other prefrontal is missing. The frontal-prefrontal suture trends anteromedially to posterolaterally to a greater degree than in Nigeremys, but about the same as in Azabbaremys.</p> <p>Structures: The dorsal margin of the apertura narium externa is entirely missing and the length of the prefrontal on the midline is indeterminate. It is quite possible that the anterior margin of the prefrontal in Arenila was the same as in Nigeremys. The prefrontal part of the orbital margin is preserved with some sign of erosion, but not as much as the anterior prefrontal edge. Presumably the margin here is close to the original. Within the fossa orbitalis of Arenila can be seen the ventral process of the prefrontal. It forms about as much of the fossa as in Azabbaremys, but differs from Azabbaremys in having a wide maxilla contact. The prefrontal forms the lateral edge of the foramen orbitonasale, although this opening is otherwise poorly preserved.</p> <p>FRONTAL (figs. 224, 227, 229)</p> <p>Preservation: The left frontal is nearly complete and only slightly distorted in TUB Vb-641. The right frontal is broken off medial to the orbital margin.</p> <p>Contacts: As in other bothremydids, the frontal of Arenila contacts the prefrontal anterolaterally, the postorbital posterolaterally, the parietal posteriorly, and the other frontal medially. The postorbital suture is short, as in Taphrosphys and Nigeremys, not long, as in Azabbaremys.</p> <p>Structures: The frontal of Arenila forms the dorsal part of the orbital margin. The degree of exposure is about the same as in Nigeremys and Azabbaremys. The sulcus olfactorius is visible in lateral view with what seems to be a deep wall, as in Azabbaremys. The frontal is relatively thick, as in Azabbaremys but in contrast to Taphrosphys and Phosphatochelys.</p> <p>PARIETAL (figs. 224, 227, 229)</p> <p>Preservation: Most of the left parietal and a small part of the right are preserved in TUB Vb-641. As with almost the entire skull, they are broken and at least partially damaged. The left processus inferior parietalis and ventral part of the right one are preserved. The preserved lateral edge of the left parietal appears broken for its anterior half, but the posterior half has a tapered, finished edge that seems to be original, all as described in Lapparent de Broin and Werner (1998: 175).</p> <p>Contacts of dorsal plate: As in other bothremydids, Arenila has a parietal with these contacts: frontal anteriorly, postorbital anterolaterally, and parietal medially. As in Nigeremys it cannot be determined due to breakage whether there was a quadratojugal contact in Arenila.</p> <p>Structures of the dorsal plate: The degree of emargination in Arenila cannot be determined. The restoration shows the minimum amount of bone present, but the parietal roof was probably more extensive than shown. It could be comparable to that restored for Nigeremys.</p> <p>Contacts of processus inferior parietalis: The processus inferior parietalis in Arenila contacts the frontal wall and continues the sulcus olfactorius anteriorly. The processus inferior parietalis extends ventrally along the anterior margin of the prootic to contact the pterygoid. The parietal appears to extend laterally under the parietal-frontal suture to contribute to the postorbital wall above the sulcus palatinopterygoideus. The presence of the postorbital in Arenila and Nigeremys is in contrast to the other members of the tribe Taphrosphyini. It is possible that the parietal in Arenila does have a descending process lateral to the sulcus palatinopterygoideus that reaches the pterygoid. However, the required suture is at present a crack and therefore ambiguous. In the dataset Arenila is given a question mark for this character.</p> <p>On the right side of TUB Vb 641, most of the processus inferior parietalis is missing, but its posteroventral part is present. It shows the posterior prootic contact above the foramen nervi trigemini and the ventral pterygoid contact anterior to the foramen nervi trigemini. Posteriorly the parietal contacts the supraoccipital as in other turtles.</p> <p>Structures of the processus inferior parietalis: The processus inferior parietalis is relatively broad in Arenila, with the margin of the foramen interorbitale more anterior than in those forms with a narrow processus, Azabbaremys and Phosphatochelys. It is not known for the other Taphrosphyini.</p> <p>The foramen nervi trigemini is formed by the prootic posteriorly, the parietal anteriorly, and the pterygoid ventrally, as in most Bothremydidae. In Arenila there is a vertical ridge anterior to the foramen that is absent in Azabbaremys but present in Phosphatochelys. It is indeterminate in the other Taphrosphyini.</p> <p>JUGAL (figs. 224, 227, 229)</p> <p>Preservation: The medial process and anterior part of the lateral plate of the left jugal are present in TUB Vb 641. The posterior edge of the lateral plate of the jugal is a broken margin, so its original extent is unknown. The sutures are clear but there is displacement and breakage along the sutures, particularly with the maxilla. As with other elements in TUB Vb 641, the bone surface is eroded and damaged.</p> <p>Contacts of lateral plate: The jugal in Arenila contacts the postorbital dorsally and the maxilla ventrally, as in other Bothremydidae. The possible quadrate and quadratojugal contacts are not determinable. Nigeremys has poor sutures, but the lateral plate of the jugal seems to contact the postorbital and maxilla as in Arenila.</p> <p>Contacts of medial process: The floor of the left orbit is badly fractured, but parts of the jugal-maxilla suture can be seen. In the postorbital wall, the jugal-postorbital contact runs dorsally from the pterygoid, as in most bothremydids. The jugal contacts the pterygoid and, more ventrally, the maxilla, although this area is badly broken with some displaced fragments.</p> <p>Structures of medial process: As in other bothremydids, the jugal of Arenila forms the lateral part of the septum orbitotemporale. The septum orbitotemporale in Arenila and Nigeremys is completely formed as in the tribe Bothremydini, but in contrast to the reduced or absent postorbital wall seen in the other Taphrosphyini.</p> <p>QUADRATOJUGAL</p> <p>Preservation: There is no identifiable part of the quadratojugal in TUB Vb 641.</p> <p>SQUAMOSAL (figs. 224, 227)</p> <p>Preservation: An eroded fragment of the right squamosal is present on the posterodorsal edge of the right quadrate and is the only remnant of the squamosal in TUB Vb 641. The only original bone surface is a small section anteromedially.</p> <p>Contacts: The only contact remaining in TUB Vb 641 is the anterior one with the quadrate.</p> <p>Structures: The squamosal remnant is probably too incomplete laterally to retain any of the antrum postoticum if one was present. In any case, there is no sign of an antrum postoticum. The squamosal in TUB Vb 641 does extend posteriorly more than the squamosal in Nigeremys, but Nigeremys is broken in this area and may have had more of a posterior extension than is preserved.</p> <p>POSTORBITAL (figs. 224, 227, 229)</p> <p>Preservation: The left postorbital is preserved in TUB Vb 642, but its posterior margin is broken and the medial process is damaged by cracks and displaced fragments. The lateral plate surface is eroded. The lateral plate sutures are clear, but the medial process ones are not.</p> <p>Contacts of lateral plate: As in other bothremydids, the postorbital of Arenila contacts the frontal anteromedially, the parietal medially, and the jugal ventrolaterally. The quadratojugal contact is missing.</p> <p>Structures of the lateral plate: As preserved, the orbital margin of Arenila shows an orbit relatively larger than the one in Nigeremys and Azabbaremys, but comparable to that in Phosphatochelys. Lapparent de Broin and Werner (1998) used the larger orbit of Arenila as a diagnostic difference from Nigeremys. However, close examination of TUB Vb 641 shows that all of the elements forming the orbital margin are abraded and eroded. The posteroventral elements (maxilla, jugal, and postorbital) seem to be particularly eroded and have edges exposing the cancellous marrow. The postorbital and jugal could be missing enough bone that, if restored, would result in an orbital margin of the size seen in Nigeremys, removing this feature as a difference between the two taxa (Lapparent de Broin and Werner, 1998). The maxilla is also damaged and the frontal is clearly lacking its original margin. Only the prefrontal comes close to retaining an original margin. We have not compensated for these missing edges in the restoration (fig. 224), so the orbit was probably smaller than in our restoration.</p> <p>Contacts of medial process: The medial postorbital process is not well preserved in TUB Vb 641, but the contacts with the pterygoid ventrally and the jugal laterally are clear. It is possible that there is a medial contact with the parietal (see Parietal) that prevents postorbital exposure in the lateral wall of the sulcus palatinopterygoideus.</p> <p>Structures of medial process: The postorbital in Arenila forms a major part of the septum orbitotemporale. The surface exposed in the posterior wall of the fossa orbitalis is partially covered in matrix, and the sutures are not clear.</p> <p>PREMAXILLA (figs. 224, 227)</p> <p>Preservation: The posterior parts of both premaxillae are preserved. The right premaxilla has come to light subsequent to the description of Lapparent de Broin and Werner (1998).</p> <p>Contacts: As preserved, there is the lateral contact with the maxilla, the posterior contact with a remnant of the vomer (on the right side), and the median contact with the other premaxilla.</p> <p>Structures on dorsal and ventral surfaces: The dorsal surface is eroded and does not clearly show the margins of openings. Posteriorly the ventral surface forms the foramen praepalatinum and a groove entering it. The triturating surface formed by the premaxilla defines the posterior margin of the midline concavity, which is laterally and posterolaterally continuous with the lingual ridge of the maxilla. The premaxilla is unusually large, as in Nigeremys and in contrast to other Taphrosphyini.</p> <p>MAXILLA (figs. 224, 227, 229)</p> <p>Preservation: When originally described only the left maxilla was known for TUB Vb 641, but now a partial right maxilla is also available. The left maxilla is much more complete and better preserved than is the right one. The left maxilla is considerably eroded on its lateral surface. Almost all of the original bone surface is gone and the margins are broken. The labial ridge has been crushed medially and the bone displaced so that the ridge is more medial to the edge of the skull than it was premortem. The triturating surface is cracked, but most of it is not eroded.</p> <p>Contacts of vertical plate: As in other bothremydids, the maxilla of Arenila contacts the premaxilla anteriorly, the prefrontal anterodorsally, and the jugal posterodorsally. The posterior contacts are unknown, but the restoration shows that the maxilla is relatively long in Arenila as it is in Azabbaremys, placing the known end of the maxilla close to the quadrate.</p> <p>Structures of vertical plate: The anterior end of the maxilla in Arenila is a broken margin with no sign of the apertura narium externa. The apertura in Arenila could have been the same as in Nigeremys. The dorsal process of the maxilla in Arenila is about as thick and high as it is in Azabbaremys, in strong contrast to the conditions in Labrostochelys or Phosphatochelys. In Nigeremys the process is the same thickness, although the suture appears to be inclined posterodorsally rather than anterodorsally as in Arenila.</p> <p>The size of the orbit has been discussed under Prefrontal. The maxilla edge is eroded in TUB Vb-641, but not as much as the postorbital and jugal margins. The labial ridge has been crushed dorsoventrally as well as medially. Considering both orbital erosion and labial ridge crushing, the suborbital depth of the maxilla must have been greater than it is now. One of the few differences between Arenila and Nigeremys is the suborbital depth of the maxilla, and we have not adjusted this for crushing in our Arenila restoration. There is no way to be sure, but it is possible that the suborbital depth was the same in both originally.</p> <p>Contacts of horizontal plate: In Arenila the maxilla contacts the premaxilla anteromedially, the palatine posteromedially, and the jugal posterolaterally, all as in other Taphrosphyini. Arenila also has a small, medial contact with the vomer, very much the same as in Nigeremys. Labrostochelys also has a vomer contact, but Azabbaremys does not. The vomer is not known for Phosphatochelys and Taphrosphys.</p> <p>Structures of horizontal plate: The triturating surface of Arenila is mostly formed by the maxilla with only a small posteromedial contribution by the palatine, as in Nigeremys and Azabbaremys. The labial ridge is very thick in Arenila and Nigeremys, thicker than in any other Taphrosphyini. The ridge is blunt in Nigeremys and acute in Arenila. The entire surface of the skull of Nigeremys has been damaged, and the labial ridge as preserved is irregular and could easily have been as acute as in Arenila before being damaged. The lingual ridge of Arenila is very low and parallel to the labial ridge, as in Nigeremys. Both have a very shallow trough between the ridges. The labial ridge is straight in Arenila and Nigeremys, not curved convex outward as in the other Taphrosphyini, except Labrostochelys. The shape of the triturating surface is similar in Arenila, Nigeremys, and Azabbaremys, except that Arenila and Nigeremys have a broader medial process reaching the vomer.</p> <p>The apertura narium interna in Arenila is very similar in shape to Nigeremys, with the thick edge of the lingual ridge of the maxilla forming its anterolateral margin. The foramen orbitonasale is present on the left side, but the thin edges are mostly broken away.</p> <p>VOMER (figs. 224, 227)</p> <p>Preservation: The anterior and posterior ends of the vomer are present in TUB Vb- 641, but the central bar is missing. The parts preserved show clear sutures.</p> <p>Contacts: The vomer of Arenila contacts the premaxilla anteriorly, the maxilla anterolaterally, and the palatine posteriorly, as in Nigeremys and Labrostochelys. In Azabbaremys there is no vomer-maxilla contact.</p> <p>Structures: Even though the vomer of Arenila lacks the central bar, the preserved parts show that the bar was thick and short, as in Nigeremys and in contrast to the very thin vomer of Azabbaremys. Enough of the two foramina praepalatinum are preserved on the premaxillae to show that the vomer may participate in the formation of these canals as described by Lapparent de Broin and Werner (1998).</p> <p>The foramen narium interna in Arenila is formed by the vomer medially, the maxilla laterally, and the palatine posteriorly. As restored, the apertura in Arenila is about the same size as in Nigeremys although much of the margin is broken and the palatine edge is largely missing. Lapparent de Broin and Werner (1998: 174) used ‘‘larger choanal’’ to distinguish Arenila from Nigeremys, but this condition is the result of postmortem breakage. Furthermore, our examination of Nigeremys shows that the apertura narium interna is larger than that depicted in Lapparent de Broin and Werner (1998: fig. 4b).</p> <p>Neither Arenila nor Nigeremys has the high degree of palatal arching seen in Azabbaremys and reflected in the vomer orientation that is more inclined in Azabbaremys than in Arenila and Nigeremys.</p> <p>PALATINE (figs. 224, 227)</p> <p>Preservation: Most of both palatines are preserved in TUB Vb 641, with some cracking along the choanal passage. A section is missing posteriorly on the right side and both palatines lack their anteromedial edges. The sutures are distinct.</p> <p>Contacts: The palatine contacts in Arenila are with the vomer anteromedially, the palatine medially, the pterygoid posteriorly, and the maxilla anterolaterally.</p> <p>Structures on the dorsal surface: Some of the contact of the palatine and the processus inferior parietalis is visible on the left side in Arenila, but it is too crushed to make detailed comparisons. The dorsal opening of the foramen palatinum posterius is formed anteriorly by the palatine, and on the left side a trough formed by palatine leads into it from the floor of the sulcus palatinopterygoideus. The sulcus itself is partially obscured by broken bone and matrix, but a parietal contact is possible. The palatine forms a major part of the fossa orbitalis floor and contacts the maxilla laterally and, possibly, the prefrontal anteriorly. The foramen orbitonasale is medial to the palatine here.</p> <p>Structures on ventral surface: As in Nigeremys and Azabbaremys, the palatine of Arenila only forms a small part of the triturating surface. A large, curved choanal passage is confluent with the apertura narium interna, as in Nigeremys.</p> <p>The foramen palatinum posterius in Arenila is formed anteriorly by the palatine and posteriorly by the pterygoid. As preserved, the foramen is very large, and Lapparent de Broin and Werner (1998) used this to distinguish Nigeremys from Arenila. Howev- er, discovery of a partial left palatine and close examination of the right palatine suggest that a smaller foramen was original and that the large one is a preservational artifact. The edges of the left foramen palatinum posterius are intersected by matrix-filled cracks that have enlarged and dislocated the margins of the foramen. When the remaining original edges are adjusted for this, the foramen is less than half the size as preserved. The foramen in Arenila is still slightly larger than in Nigeremys.</p> <p>QUADRATE (figs. 224–230)</p> <p>Preservation: Only the left quadrate is present in TUB Vb 641and almost all of it is badly damaged by erosion that has removed a large percentage of the bone. Only a small contact with the rest of the skull remains, and only a few areas of original bone surface are present.</p> <p>Lateral view contacts: None of the cheek or skull roof contacts is preserved in Arenila. A block of the eroded squamosal is present on the posterodorsal part of the quadrate. Only the internal contact is preserved.</p> <p>Lateral view structures: Only a small vestige of the cavum tympani is preserved in Arenila, and this is the medial wall of the sulcus eustachii. The canal for the columella auris is eroded away where it reaches the cavum tympani as described by Lapparent de Broin and Werner (1998). The distance between the sulcus eustachii and the stapedial canal is slightly shorter in Arenila than it is in Nigeremys, as noted by Lapparent de Broin and Werner (1998), but in neither taxon is that distance very different from that in Azabbaremys. The antrum postoticum is entirely missing. This may not be due only to erosion, as it is likely that if a moderate or tubelike antrum were present there would be some of it visible. It is likely that the antrum postoticum was actually absent in Arenila as in Azabbaremys.</p> <p>Dorsal view contacts: The dorsal parts of the quadrate are missing due to erosion in TUB Vb 641.</p> <p>Dorsal view structures: The extensive erosion of the quadrate in Arenila has exposed the canalis stapedio-temporalis, but the foramen stapedio-temporale has its ventral margin preserved. The foramen faces anteriorly, as in Azabbaremys.</p> <p>Ventral and posterior view contacts: The medial contacts with the pterygoid, basisphenoid, and basioccipital are preserved at least in part on the right side in Arenila. There is a broken section between the quadrate and basisphenoid-basioccipital. The pterygoid has a small fragment attached to the quadrate anteriorly just lateral to the broken section, allowing restoration of the pterygoid limits. In posterior view the quadrate contacts the exoccipital ventromedially. As described by Lapparent de Broin and Werner (1998), most or all of the opisthotic is missing on both sides.</p> <p>Ventral and posterior view structures: Laterally, the quadrate in Arenila preserves a horizontal ridge on its posterior surface that seems to continue the line formed by the sulcus eustachii. Dorsomedially, the trough above this ridge runs into the fenestra postotica. Very little of the quadrate and none of the opisthotic are preserved to show the extent and shape of the fenestra postotica in Arenila.</p> <p>Ventrally the processus articularis and condylus mandibularis are preserved on their posterior surface, but the anterior and lateral surfaces are gone. The position of the condylus mandibularis is slightly posterior to the condylus occipitalis in Arenila, as in Nigeremys but in contrast to the more anterior position of other Taphrosphyini. The fossa pterygoidea is large and deep in Arenila, as it is in Nigeremys. The pterygoid flange of the quadrate forms the posteromedial wall of this concavity, and this is preserved in Arenila. The foramen posterius canalis carotici interni in Arenila has no contribution by the quadrate (see Basisphenoid), contrary to Lapparent de Broin and Werner (1998).</p> <p>PTERYGOID (figs. 224–229)</p> <p>Preservation: Parts of both right and left pterygoids are present in TUB Vb 641, but both are incomplete. The anteromedial plate is present on both sides, and on the right side most of the quadrate process is present. When described by Lapparent de Broin and Werner (1998) only the left processus trochlearis pterygoidei was present, but the right one has now been found, which helps correct a misconception about its orientation (see below).</p> <p>Ventral surface contacts: As in other Taphrosphyini, the pterygoid of Arenila contacts the palatine anteriorly, the basisphenoid posteromedially, the quadrate posterolaterally, and other pterygoid medially. As in Nigeremys, the midline pterygoid contact is very narrow in Arenila.</p> <p>Ventral surface structures: The left processus trochlearis pterygoidei in TUB Vb 641 is distorted in its position as preserved. The posterolateral end has been rotated medially, making the processus seem larger and parallel to the midline. The apparent size increase is due to matrix and bone debris filling the opened contact between the pterygoid and palatine. The distortion has also affected the size of the foramen palatinum posterius, making it larger than in its original state (see Palatine). Also, the newly discovered right processus trochlearis pterygoidei shows a more ‘‘normal’’ position. When restored, the processus in Arenila is not unusually large, similar to Nigeremys when its erosion is accounted for.</p> <p>The fossa pterygoidea is present in Arenila (see Quadrate), as in Nigeremys. The pterygoid forms the anterolateral part of the concavity. The foramen posterius canalis carotici interni (see Basisphenoid) is formed in the pterygoid-basisphenoid suture.</p> <p>Dorsal surface contacts: Some of the dorsal part of the pterygoid in Arenila is visible. At the base of the processus trochlearis pterygoidei, there is a lateral contact with the jugal, an anterodorsal one with the postorbital, and probably a dorsomedial one with the parietal (see Parietal). The crista pterygoidea forms the ventral margin of the foramen nervi trigemini, with the parietal forming the anterior margin and the prootic the posterior margin. The foramen is relatively large, as in Azabbaremys (not visible in Nigeremys).</p> <p>SUPRAOCCIPITAL (figs. 224–230)</p> <p>Preservation: Most of the supraoccipital is present in TUB Vb 641, but its posterior margin is a broken edge so its complete limits are not known.</p> <p>Contacts: As in other Taphrosphyini, the supraoccipital of Arenila contacts the parietal dorsally, the prootic anterolaterally, and the exoccipital posteroventrally. The presumed quadrate and opisthotic contacts are not preserved.</p> <p>Structures: The crista supraoccipitalis in Arenila is longer than in Nigeremys and Azabbaremys, although the bone in Nigeremys may be eroded. The crista in Arenila is nearly twice the length that it is in Azabbaremys. A low ridge is present on the crista supraoccipitalis in Arenila, about one-third of the way above the foramen magnum. The trough below this ridge opens into the large concavity on the exoccipital (see Exoccipital). This ridge is not in Azabbaremys or Nigeremys.</p> <p>EXOCCIPITAL (figs. 224, 229, 230)</p> <p>Preservation: Both exoccipitals are present in TUB Vb 641 and are nearly complete with clear sutures.</p> <p>Contacts: As in other Taphrosphyini, the exoccipital of Arenila contacts the supraoccipital dorsally, the quadrate ventrolaterally, and the basioccipital ventrally. The presumed lateral contact with the opisthotic is missing.</p> <p>Structures: The foramen magnum of Arenila is very similar in size and shape to that in Azabbaremys and Nigeremys (which is somewhat eroded). The condylus occipitalis is formed completely by the exoccipitals. There is one foramen nervi hypoglossi very close to the much larger foramen jugulare posterius. In Azabbaremys, there are two foramina nervi hypoglossi and they are separated from the foramen jugulare posterius. In Arenila, the foramen nervi hypoglossi is facing almost laterally, just on the margin of the foramen jugulare posterius, a condition similar to that seen in Taphrosphys.</p> <p>BASIOCCIPITAL (figs. 224, 227, 230)</p> <p>Preservation: The basioccipital in TUB Vb 641 is present, nearly complete, with clear sutures. Its posterolateral margins are damaged on both sides but not much can be missing, due to the presence of the quadrate.</p> <p>Sutures: As in other Taphrosphyini, the basioccipital in Arenila contacts the basisphenoid anteriorly, the quadrate laterally, and the exoccipitals dorsally.</p> <p>Structures: The basioccipital in Arenila is pinched off by the exoccipitals on the neck of the condylus occipitalis and does not reach that structure. The tuberculum basioccipitale is only a low, horizontal ridge at the posterior margin of the basioccipital, very similar to that in Azabbaremys. The area is damaged in Nigeremys. Most of the basioccipital in Arenila forms a broad concavity, much deeper than the one in Azabbaremys but similar to the poorly preserved one in Nigeremys. As in Azabbaremys and probably Nigeremys, the basioccipital of Arenila is wide and short, in contrast to the much longer one in Taphrosphys.</p> <p>PROOTIC (figs. 224, 229)</p> <p>Preservation: Both prootics are present in TUB Vb 641, but the right one is nearly complete and has clear sutures while the left one is more crushed and obscured by matrix. The right prootic has no dorsal contact and ends in a broken margin.</p> <p>Contacts: As in other Taphrosphyini, the prootic of Arenila contacts the parietal dorsomedially (visible on left side), the supraoccipital posterodorsally, and the pterygoid ventrally. The opisthotic is missing its contacts represented by broken margins on the prootic. The left and most of the right quadrate are also missing and the possibility of a quadrate-supraoccipital cannot be excluded.</p> <p>Structures: The foramen nervi trigemini in Arenila is formed by the usual suspects: parietal anteriorly, pterygoid ventrally, and prootic posteriorly. The foramen is oblong and, as preserved on the right side, has a larger posterior part and a smaller, anteroventral part, probably reflecting the division of the trigeminal ganglion into two branches at this point (one branch separating medially, see Gaffney, 1979a). However, the left foramen nervi trigemini (which does not seem to be as well preserved as the right one) is an oval. Although it is hard to judge the relative sizes of this foramen among skulls widely varying in size, it seems that Arenila and Azabbaremys have relatively large foramina compared to Taphrosphys. Phosphatochelys also seems to have a relatively large foramen. The opening is not visible in Nigeremys.</p> <p>The foramen stapedio-temporale in Arenila is represented only by a part of the ventrolateral margin on the right quadrate. The area of the prootic-quadrate suture is damaged and the full extent of the foramen is not determinable; however, it is clearly on the anterior face of the otic chamber and close to the foramen nervi trigemini.</p> <p>OPISTHOTIC</p> <p>Preservation: The opisthotic is not preserved in TUB Vb 641, except possibly as fragments on the right side.</p> <p>BASISPHENOID (figs. 224, 227)</p> <p>Preservation: The basisphenoid in TUB Vb 641 is nearly complete, but its posterolateral margins end in broken edges. On the right side only a small amount of basisphenoid can be missing because the quadrate is separated from the basisphenoid only by a narrow gap. Only the ventral surface of the basisphenoid is visible.</p> <p>Contacts in ventral view: As in other Taphrosphyini, the basisphenoid contacts in Arenila are: pterygoids anterolaterally, quadrate posterolaterally, and basioccipital posteriorly. The basisphenoid-quadrate contact in Arenila is very narrow, as in Azabbaremys and Labrostochelys. The contact is indeterminate in Nigeremys. The basioccipital-basisphenoid suture in Arenila and Nigeremys is curved sharply, convex anteriorly, in contrast to all other Taphrosphyini in which it is straight.</p> <p>Structures in ventral view: The foramen posterius canalis carotici interni is formed mostly by the basisphenoid in Arenila, with the anterolateral margin formed by the pterygoid. A short groove formed by the basisphenoid leads anteromedially into the foramen. Lapparent de Broin and Werner (1998:179, fig. 12a) figured the foramen posterius canalis carotici as being at the junction of three elements: quadrate, basisphenoid, and pterygoid. Further preparation and close examination of this area confirms that the quadrate is some distance posterior to the foramen. The foramen and groove are visible on both sides. In our interpretation, the area described by Lapparent de Broin and Werner (1998) as forming the foramen posterius canalis carotici interni is the narrow gap between the quadrate and basisphenoid. Nonetheless, TUB Vb 641 is not well preserved in this area and multiple interpretations are possible.</p> <p>The basisphenoid in Arenila forms the medial wall of the fossa pterygoidea (the ‘‘podocnemidid fossa’’ of Lapparent de Broin and Werner, 1998), a large concavity also found in Nigeremys but no other Taphrosphyini (see Pterygoid or Quadrate). At the anteriormost margin of the basisphenoid in TUB Vb 641 are small, paired foramina, just adjacent to the pterygoid suture. Preparation of these show that each leads into a small anteriorly trending canal. The contents of these foramina are unknown.</p> <p>LOWER JAW MORPHOLOGY</p> <p>The lower jaw in pleurodires has never been treated systematically, although Fuchs (1931), Poglayen-Neuwall (1953), and Gaffney (1979a) have useful coverage. As with the skull, the following descriptions follow a standard pattern outlined in appendix 1. Tables 20 and 21 give comparisons of lower jaws in pleurodires, particularly those described here.</p> <p>FAMILY EURAXEMYDIDAE Euraxemys essweini MATERIAL AVAILABLE: In FR 4922 (figs. 231, 232), the right ramus of the lower jaw is complete and the left ramus is gone posterior to the coronoid process. Both rami are well preserved, free of matrix with clear sutures.</p> <p>DENTARY</p> <p>Preservation: The right dentary is complete; the left one is missing its posterior margin.</p> <p>Contacts: The dentary in Euraxemys contacts the coronoid posterodorsally, the surangular posteriorly, and the angular posteroventrally. There is a narrow contact with the prearticular on the medial surface, below the coronoid.</p> <p>Structures: The dentaries in Euraxemys seem to be separated on the midline symphysis by a suture. As preserved, they are separate, with the contact area on both rami being a mixture of what looks like a sutural surface and broken bone. The jaws are also sutured in Araripemys and most chelids, but not in Emydura, while the jaws in bothremydids and podocnemidids are fused.</p> <p>The symphysis in Euraxemys is rounded and not pointed or protuberant as in many other pleurodires. The jaw is not greatly thickened at the symphysis. In Araripemys the symphysis and jaw are quite thin, similar to chelids like Chelodina and Hydromedusa. Euraxemys has a thicker jaw, very close in proportions to Emydura and Elseya, but without the protuberant symphysis.</p> <p>The triturating surface in Euraxemys is roughly parallel-sided, slightly wider anteriorly and narrowing posteriorly. The labial ridge is sharp and much higher than the lingual ridge, which is only the medial edge of the triturating surface. The surface itself is slightly concave and sharply tilted medially, much as in Elseya latisternum (AMNH 103700).</p> <p>On the external surface, the dentary of Euraxemys forms the processus coronoideus with the coronoid bone on the medial surface of the processus. The processus coronoideus in Pelomedusoides does not vary a great deal and its size in Euraxemys is about the same as in pelomedusids and Emydura. Just below the processus is a distinct foramen, the foramen dentofaciale majus. Posterodorsally the dentary contacts the surangular and posteroventrally it contacts the angular.</p> <p>The medial surface of the dentary has a distinct groove below the triturating surface, the sulcus cartilaginis meckelii. In Euraxemys the sulcus becomes prominent posterior to the symphysis, as in Elseya, rather than extending closer to it, as in Pelusios. The sulcus leads posteriorly into the foramen intermandibularis medius. Within the dentary, just anterior to this foramen is the foramen alveolare inferius, as it is in chelids and other Pelomedusoides. The medial contacts of the dentary are with the coronoid posterodorsally, the prearticular posteriorly, and the angular posteroventrally.</p> <p>ANGULAR</p> <p>Preservation: The right angular is complete in FR 4922; the left one lacks its posterior end.</p> <p>Contacts: The angular of Euraxemys contacts the dentary anteriorly, the prearticular dorsally, the articular posteriorly, and the surangular dorsally on the lateral surface.</p> <p>Structures: The angular of Euraxemys is a long, thin bone that begins anteriorly on the medial surface and bends posteroventrally to end below the articular bone. The foramen intermandibularis caudalis is formed in the prearticular-angular suture and it opens into the fossa meckelii. The angular in Araripemys extends more anteriorly than in Euraxemys, which is similar in extent to Pelusios. In Emydura and Elseya the large</p> <p>TABLE 20</p> <p>Comparison of Lower Jaws 1 TABLE 21 Comparison of Lower Jaws 2</p> <p>splenial lies above the angular. In all Pelomedusoides, including Euraxemys, the splenial is absent. The angular in Euraxemys goes posteriorly to the end of the jaw separating the prearticular and surangular and curves posterodorsally to contact the surangular on the lateral surface of the jaw.</p> <p>SURANGULAR</p> <p>Preservation: The right surangular is complete in FR 4922; only a fragment of the left one remains.</p> <p>Contacts: The surangular in Euraxemys contacts the dentary anteriorly, the coronoid in a narrow contact anterodorsally, the angular posteroventrally, and the articular posteromedially.</p> <p>Structures: The surangular in Euraxemys is a large element lying on the external surface at the posterior end of the jaw. The surangular is a flat plate that forms the lateral wall of the fossa meckelii and the lateral margin of the area articularis mandibularis. The fossa meckelii in Euraxemys is about the same size as in Emydura and slightly smaller than in pelomedusids. It is much smaller than in Proganochelys.</p> <p>On the external surface of the surangular in turtles are a series of foramina that transmit branches of the mandibular branch of the trigeminal nerve (VII 3). These foramina are particularly variable in pleurodires but the largest is usually referred to as the foramen nervi auriculotemporalis. Fuchs (1931) described this area and these nerves in Podocnemis, and Poglayen-Neuwall (1953) described the area in a number of cryptodires and pleurodires. The foramen nervi auriculotemporalis transmits the nervus auriculotemporalis, which has at least two branches and an anastomosis (Fuchs, 1931: figs. 8, 10). In podocnemidids the foramen and associat- ed canals are large and complex, in other pleurodires they are usually smaller. Howev- er, in Euraxemys, pelomedusids, and Hamadachelys, the foramen approaches the podocnemidid condition. In Emydura / Elseya, and Araripemys the foramen is small and comparatively inconspicuous. In Emydura / Elseya the foramen is a simple hole penetrating the surangular from the fossa meckelii to the external surface. In pelomedusids the foramen nervi auriculotemporalis opens on the external surface above a short canal that extends ventrally beneath a short strap of bone to open more ventrally still on the external surface of the surangular. The contents of this short canal are presumed to be a branch of the nervus auriculotemporalis, but the canal is not described in the literature. In Euraxemys there is a similar canal on the right surangular (the left one is missing), but it is opened laterally by erosion and does not form a completely enclosed canal as preserved. Nonetheless, it is very similar to that canal in pelomedusids. Anteriorly, the foramen nervi auriculotemporalis penetrates medially and anteriorly into another canal in the surangular that also opens on the external surface of the surangular a short distance from the foramen nervi auriculotemporalis proper. The senior author has not seen a parallel structure in other pleurodires. This canal also is presumed to contain a branch of the nervus auriculotemporalis. Fuchs (1931) described one of the multiple foramina nervi auriculotemporalis (the largest) as being combined with the apertura lateralis canalis transversi into a larger, combined foramen that opens on the external surface of the surangular. The senior author has not been able to determine its contents, but these structures clearly vary among podocnemidids and on each side of the jaw as well.</p> <p>In Euraxemys there is only one foramen penetrating the surangular from the external surface into the fossa meckelii. This is also the case in Podocnemis. There is a posterior foramen and canal just behind the foramen nervi auriculotemporalis in AMNH specimens of Podocnemis, and this appears to be the apertura lateralis canalis transversi of Fuchs (1931). However, this canal goes posteriorly into the articular bone and does not enter the fossa meckelii. Is this the posterior path of the nervus auriculotemporalis? Is it Fuchs’ apertura lateralis canalis transversi? It does not sound like it.</p> <p>The surangular forms the entire lateral wall of the fossa meckelii. The internal surface of the fossa is visible in Euraxemys. Its lateral wall is formed anteriorly by the dentary, which has a vertical suture with the surangular just anterior to the dorsal opening of the fossa meckelii. The anterior opening of the fossa is the foramen intermandibularis CORONOID</p> <p>Preservation: Both coronoids are complete in FR 4922.</p> <p>Contacts: The coronoid in Euraxemys contacts the dentary anterolaterally, the prearticular ventromedially, and the surangular posterolaterally.</p> <p>Structures: The coronoid bone in Euraxemys lies on the medial surface of the dentary, forming the medial half of the processus coronoideus. It contacts the dentary anterolaterally, the prearticular ventromedially, and the surangular posterolaterally. The processus coronoideus does not vary a great deal in size among Euraxemys, Emydura / Elseya, pelomedusids, and Araripemys. It is slightly higher in these taxa than in Podocnemis. The coronoid extends anteriorly to a greater extent in pelomedusids, chelids, and Araripemys than it does in Euraxemys. As in chelids and pelomedusids, the coronoid is only barely visible in lateral view in Euraxemys. More of it is exposed laterally in Araripemys.</p> <p>medius formed laterally by the dentary and medially by the prearticular. The very narrow floor of the fossa slopes ventrally into the foramen intermandibularis caudalis and is mostly formed by the angular. Between the angular and prearticular is the foramen intermandibularis caudalis. The posterior wall of the fossa meckelii is formed by the articular sandwiched between the prearticular and surangular. The canal for the chorda tympani lies lateral to the articular. The surangular forms the lateral quarter or so of the area articularis mandibularis, as in most turtles. In Euraxemys there is a clear suture between the articular and surangular.</p> <p>ARTICULAR</p> <p>Preservation: The right articular in FR 4922 is complete; the left one is gone.</p> <p>Contacts: The articular in Euraxemys contacts the surangular laterally, the angular anteroventrally, and the prearticular medially.</p> <p>Structures: The articular is a triangular-shaped element lying at the posterior end of the jaw. In Euraxemys it is exposed dorsally and posteriorly and is sandwiched between the surangular laterally and the prearticular medially. It contacts the angular anteroventrally. As in chelids, the area articularis mandibularis of Euraxemys is more flat than convex and faces posterodorsally. The area is not strongly convex as in pelomedusids and podocnemidids. Rather, the surface is gently convex, dropping off laterally to the part of the surface on the surangular.</p> <p>The articular pinches out anteriorly where a thin section of it forms the posterior wall to the fossa meckelii. At the posteroventral end of the fossa meckelii, laterally in the suture between articular and prearticular, is the foramen anterius chorda tympani. The foramen posterius chorda tympani is on the outside of the jaw, on the posteromedial edge of the area articularis mandibularis. It is also formed by the prearticular medially and the articular laterally and lies at the base of a depression on the retroarticular process. This is similar to the chorda tympani foramina in Hamadachelys. In chelids and Araripemys the foramen posterius chorda tympani is more anterior and not adjacent to the articular surface. Emydura / Elseya and Hamadachelys have retroarticular processes much as in Euraxemys, while Araripemys and pelomedusids lack them. A very similar condition of the entire back end of the jaw is in AMNH 63579, Erymnochelys madagascariensis. However, in Podocnemis the retroarticular process is depressed and separated below the level of the area articularis mandibularis.</p> <p>PREARTICULAR</p> <p>Preservation: The right prearticular in FR 4922 is complete; the left one is missing its posterior half or so.</p> <p>Contacts: The prearticular in Euraxemys contacts the coronoid anterodorsally, the articular posteromedially, and the angular ventrally.</p> <p>Structures: The prearticular in Euraxemys is a long, thin sheet extending from the coronoid bone posteriorly on the medial surface to the retroarticular process. Anteriorly it forms the posterior margin of the foramen intermandibularis medius, which opens into the fossa meckelii. In Emydura / Elseya this area is formed by the splenial, but in Pelomedusoides the prearticular extends anteriorly to replace it. The prearticular in Euraxemys extends anteriorly farther than in Araripemys and pelomedusids. The dorsal edge of the prearticular forms the medial margin of the upper opening of the fossa meckelii. It is slightly higher than in Emydura / Elseya and slightly lower than in Araripemys.</p> <p>The ventral margin of the prearticular in Euraxemys is a long straight suture with the angular. About halfway along it is an opening, the foramen intermandibularis caudalis. It opens between the medial jaw surface and the ventral part of the fossa meckelii. The foramen is in about the same position in chelids, pelomedusids, Araripemys, and Euraxemys. On the medial surface of the prearticular, in the floor of the fossa meckelii, the foramen anterius chorda tympani is formed between the prearticular and the articular.</p> <p>The posterior end of the prearticular covers the articular laterally. It does not bear any of the area articularis mandibularis. A small part of the prearticular is exposed dorsally at the posteromedial corner of the area articularis mandibularis where it forms the medial half of the foramen posterius chorda tympani. The articular forms the lateral half of the foramen. Presumably the canalis chorda tympani is formed between the prearticular and the articular.</p> <p>FAMILY BOTHREMYDIDAE</p> <p>TRIBE KURMADEMYDINI Kurmademys kallamedensis (fig. 233) MATERIAL AVAILABLE: ISI 155E, a nearly complete jaw, lacking the left posterior end; ISI 155D, both rami and symphysis, lacking the left coronoid region and some of the triturating surface; ISI 155F, a partial right ramus.</p> <p>DENTARY</p> <p>Preservation: The dentary is almost entirely complete on the right side of ISI 155E, with some cracking. The left side is complete as well, except for a small part of the posterior end. In ISI 155D, the dentary is mostly present but is slightly eroded and missing the area around the left processus coronoideus and part of the right triturating surface. In ISI 155F, only the symphysis and most of the right dentary are present.</p> <p>Contacts: The dentary contacts in Kurmademys are the same as in Cearachelys: coronoid posterodorsally, surangular posterolaterally, angular posteroventrally, and prearticular posteromedially. The surangular contact is vertical beneath the processus coronoideus, not as far anterior as in Bothremys, but more anterior than in Euraxemys.</p> <p>Structures: The symphysis in Kurmademys is similar to that in Cearachelys, an upturned labial ridge with a U-shaped concavity behind a narrow triturating surface defined by a low lingual ridge. Based on ISI 155F and ISI 155D, the symphyseal anterior margin is projected dorsally into a curved hook, but in ISI 155E the symphysis is low, as in Cearachelys. The triturating surface of Kurmademys is very similar to that in Cearachelys, with a low labial ridge turned dorsally at its posterior end, and a higher lingual ridge. In ISI 155E the shallow concavity at the posterior end of the triturating surface is about as deep as it is in Cearachelys, but in ISI 155D the concavity is shallower and the triturating surface is narrower.</p> <p>The sulcus cartilaginus meckelii does not meet on the symphysis; it is similar to that in Cearachelys, being formed anteriorly by the dentary, and merging with the symphyseal concavity. On the lateral surface of the dentary is the foramen dentofaciale majus, just below the posterior end of the triturating surface, as in Cearachelys.</p> <p>ANGULAR</p> <p>Preservation: A nearly complete right angular and a partial left one are present in ISI 155E. Both angulars are complete in ISI 155D, but the left one is slightly damaged. The anterior half of the right angular is present in ISI 155F.</p> <p>Contacts: As in Cearachelys, the angular in Kurmademys contacts the dentary anteriorly, the prearticular dorsally, the articular posteriorly, and the surangular dorsolaterally. The prearticular contact is long, as in Cearachelys and Euraxemys but in contrast to Bothremydini and Taphrosphyini. The articular contacts are not visible.</p> <p>Structures: The angular in Kurmademys is very similar to that in Cearachelys, wrapping around from the sulcus cartilaginis meckelli to the surangular laterally.</p> <p>SURANGULAR</p> <p>Preservation: The right surangular is complete in ISI 155E, with the left one missing posteriorly. In ISI 155D the right one is cracked and missing a few areas; the left one is only present ventrally.</p> <p>Contacts: As in Cearachelys, the surangular of Kurmademys contacts the dentary anteriorly, the coronoid anterodorsally, the angular posteroventrally, and the articular posteromedially.</p> <p>Structures: The surangular in both Cearachelys and Kurmademys has a shallow, laterally facing depression that covers the lateral surface of the jaw, which is better defined in Kurmademys. The foramen nervi auriculotemporalis is just anteroventral to the area articularis mandibularis, as in Cearachelys. Also as in Cearachelys, the surangular forms the anterolateral margin of the area. The surangular extends posteriorly on the lateral surface of the processus retroarticularis.</p> <p>CORONOID</p> <p>Preservation: Both coronoids are present and largely complete in ISI 155E. In ISI 155F the right coronoid is present, as it is in ISI 155D.</p> <p>Contacts: The coronoid contacts in Kurmademys are very similar to those in Cearachelys. There is only a small lateral exposure of the coronoid above the dentary-surangular contact. On the medial surface the prearticular has a posteroventral contact, as in Cearachelys.</p> <p>Structures: The processus coronoideus in Kurmademys is formed medially by the coronoid, as in Cearachelys. The processus is better defined and slightly higher in Cearachelys than in Kurmademys. The coronoid in Kurmademys extends anteroventrally onto the triturating surface, just dorsal to the concavity on the dentary. In Cearachelys the coronoid barely forms the margin of the triturating surface. A very narrow surangular-prearticular contact prevents the coronoid from entering the dorsal opening of the fossa meckelii.</p> <p>ARTICULAR</p> <p>Preservation: The articular is present and complete on the right side of ISI 155E and on the left side of ISI 155D.</p> <p>Contacts: Most of the articular sutures in ISI 155D and ISI 155E are fused, but the surangular contact, anterolaterally, is visible.</p> <p>Structures: The area articularis mandibularis in ISI 155E is slightly narrower than in Cearachelys, but in ISI 155D it is the same width. The surface shape is the same in both Kurmademys and Cearachelys.</p> <p>PREARTICULAR</p> <p>Preservation: None of the Kurmademys jaws has a complete prearticular, but the preserved areas are overlapping. The right prearticular in ISI 155E is the best, missing only some of the fossa meckelii margin. In the right prearticular of ISI 155D, the anterior part is missing. In ISI 155F, the anterior part is present on the right ramus.</p> <p>Contacts: As in Cearachelys, the prearticular of Kurmademys contacts the coronoid anteriorly, the articular posteromedially, and the angular ventrally. The angular contact is long, as in Cearachelys, enclosing the fossa meckelii to a greater extent than in Bothremydini and Taphrosphyini. The foramen intermandibularis medius, therefore, is more anterior in Kurmademys and Cearachelys than in the latter tribes.</p> <p>TRIBE CEARACHELYINI Cearachelys placidoi (fig. 234)</p> <p>MATERIAL AVAILABLE: THUg 1798, complete let ramus, symphysis, right ramus with articular region intact but most of remaining bone eroded away, associated with a skull and shell; BSP 1976 I 160, a nearly complete lower jaw with symphysis fragmented and distorted, associated with skull and shell.</p> <p>DENTARY</p> <p>Preservation: The dentary of BSP 1976 I 160 is nearly complete except for the symphysis. The left dentary in THUg 1798 is nearly complete, but most of the right one is missing.</p> <p>Contacts: The dentary in Cearachelys contacts the coronoid posteromedially, the surangular posterolaterally, and the angular posteroventrally. The surangular contact is nearly vertical directly beneath the processus coronoideus, as in Kurmademys. The anterior extent of the surangular and restriction of the dentary exposure in lateral view occur in the Bothremydini, Taphrosphyini, and Kurmademys, but not in Euraxemys, chelids, or pelomedusids.</p> <p>Structures: As in all bothremydids, the symphysis is fused, with no sign of a suture in Cearachelys. The symphyseal area in Cearachelys is similar to that in Kurmademys, with a narrow triturating surface and a deep Ushaped concavity behind it. The concavity is below the level of the triturating surface, not raised into a symphyseal wedge, as in Bothremys cooki.</p> <p>The dentary in Cearachelys extends posteriorly on the lateral surface ventral to the surangular to a point below the middle of the area articularis. On the medial surface it is hidden from view below the coronoid process by contact between the prearticular and angular. The labial ridge is lower than the lingual ridge except at the symphysis. Its lateral edge is slightly concave in outline. The lingual ridge is taller than the labial ridge except where they are even at the symphysis. It is tallest where it contacts the coronoid and then becomes progressively lower anteriorly. It remains distinct to the symphysis where it produces the U-shaped central concavity.</p> <p>The triturating surface in Cearachelys is wider posteriorly than anteriorly. There is a very weakly developed pit in the posterolateral part of the dentary. The medial and posterior walls of the pit are formed by the dentary. There is no lateral wall, no roof, and no contribution by the coronoid. Although the symphysis is pointed anteriorly, there is no symphyseal hook. The symphysis is blunt, as in Kurmademys.</p> <p>The sulcus cartilaginis meckelii in Cearachelys is open for a very short distance. It is closed at the symphysis and where the prearticular meets the angular ventral to the coronoid process. The foramen intermandibularis medius and the foramen alveolare inferius are not well defined. A foramen dentofaciale majus is present on the lateral side of the dentary just ventral to the small dentary pit. The presence of nutritive foramina indicates that the rhamphotheca of the mandible covered the dorsalmost part of the dentary and the adjacent coronoid.</p> <p>The dentary of Cearachelys differs significantly from that of Bothremys. Well, not all that significantly. In general, the triturating surface is narrower throughout its length. Furthermore, the labial ridge of the dentary is much lower, and neither it or the coronoid contributes to the dentary pit as they do in Bothremys. Cearachelys is similar to B. maghrebiana but differs from B. cooki in having the U-shaped structure formed by the labial ridges meeting on the symphysis. The symphyseal wedge seen in B. cooki is absent in Cearachelys. This U-shaped structure is found in other bothremydid jaws, including those of Araiochelys, Chedighaii barberi, and AMNH 29989. It is absent from jaws of the Taphrosphyini.</p> <p>The dentary of Cearachelys is like that of B. cooki, Araiochelys, and Rhothonemys in having the sulcus cartilaginis meckelii closed anteriorly. It is like Araripemys and Kurmademys in having the posterior limit of the sulcus below the coronoid process where it is closed by an anterior meeting of the prearticular and angular.</p> <p>The dentary of Cearachelys is most similar to that of Kurmademys. They have a high lingual ridge and a low labial ridge rising posteriorly to form a distinctive, anterodorsally facing concave portion of the triturating surface. This morphology may be interpreted as primitive for Bothremydidae. A greater degree of depression at the posterior end of the triturating surface would produce the pit seen in Araiochelys and Bothremys.</p> <p>The lower jaws of BSP 1976 I 160 and THUg 1798 differ in the width of the triturating surface and the posterior height of the lingual ridge. The larger jaw, BSP 1976 I 160, has a wider triturating surface posteriorly, and the lingual ridge here is higher. The jaw of THUg 1798 is about one-third smaller than that of BSP 1976 I 160 and these differences may be due to growth, as in many living turtles.</p> <p>The foramen dentofaciale majus is formed entirely by the dentary, anterior to the surangular contact, and below the posterior end of the labial ridge.</p> <p>ANGULAR</p> <p>Preservation: The angular is nearly complete on both sides of BSP 1976 I 160 and on the left side of THUg 1798 (only part of the right one remains). The posterior sutures are unclear in both jaws.</p> <p>Contacts: The angular in Cearachelys contacts the dentary anteromedially, the prearticular dorsally, the articular posteriorly, and the surangular dorsolaterally. These contacts are very similar to those in Kurmademys. In the tribes Bothremydini and Taphrosphyini the prearticular contact is much shorter. The posterior contacts are not well defined but are visible in parts of both specimens.</p> <p>Structures: The angular forms the ventral margin of the fossa meckelii and its anterior continuation, the sulcus cartilaginis meckelii. As in Kurmademys, the sulcus stops well short of the symphysis. The angular wraps ventrally around the posterior part of the jaw. This area is very similar in both Cearachelys and Kurmademys.</p> <p>SURANGULAR</p> <p>Preservation: The surangular is present on both sides of BSP 1976 I 160, but there is postmortem damage in the form of pitting and cracks. The left surangular is present in</p> <p>THUg 1798; its surface is slightly damaged, but it is nearly complete.</p> <p>Contacts: The surangular in Cearachelys contacts the dentary anteriorly in a nearly vertical suture below the coronoid, as in Kurmademys. The surangular is more extensive anteriorly than in Euraxemys, chelids, and pelomedusids, but not as much as in the Bothremydini. The surangular contacts the angular posteroventrally and the articular posteriorly.</p> <p>Structures: In the lateral surface of the surangular, just anteroventral to the area articularis mandibularis, is the foramen nervi auriculotemporalis. The foramen can be traced within the surangular to its entrance into the fossa meckelii, anterior to the articular. The Bothremydini and Taphrosphyini seem to lack this foramen.</p> <p>The surangular in Cearachelys extends posterolaterally around the articular and forms part of the edge of the area articularis mandibularis. It does not seem to form as much of the area as it does in Euraxemys. The surangular extends laterally onto the processus retroarticularis, which is almost entirely formed by the articular. The fossa meckelii in Cearachelys is narrow, as in other bothremydids, with the lateral surangular wall being higher than the medial prearticular wall.</p> <p>CORONOID</p> <p>Preservation: The coronoid is nearly complete on the left side of BSP 1976 I 160; it is slightly damaged on the right side. In THUg 1798 the left coronoid is nearly complete, but the right one is only represent- ed by a fragment.</p> <p>Contacts: The coronoid in Cearachelys contacts the dentary anterolaterally, the prearticular ventromedially, and the surangular posterolaterally. The coronoid is less exposed laterally in both Cearachelys and Kurmademys than it is in Bothremydini and Taphrosphyini, due to a greater coronoidsurangular contact. The coronoid-dentary contact in Cearachelys does not extend as far laterally as it does in Kurmademys.</p> <p>Structures: The coronoid forms the short but distinct processus coronoideus in Cearachelys. The coronoid extends ventrally on the medial surface to form the dorsal edge of the sulcus cartilaginis meckelii. It does not form any of the triturating surface.</p> <p>ARTICULAR</p> <p>Preservation: The articular is present on both sides of BSP 1976 I 160 and THUg 1798, with some damage on the left side of BSP 1976 I 160.</p> <p>Contacts: The articular contacts the surangular laterally, the angular ventrally, and the prearticular medially.</p> <p>Structures: The area articularis mandibularis in Cearachelys is convex, with a very low ridge anteroposteriorly, as in most Bothremys. The area is wider in BSP 1976 I 160 than in Kurmademys, but in THUg 1798 it is intermediate in width. The articular forms a narrow part of the posterior edge of the fossa meckelii.</p> <p>The processus retroarticularis in Cearachelys is short, wide, and relatively massive, similar to that in Chedighaii. It is as long as in Kurmademys but wider. There is a well-defined groove on the medial surface for the chorda tympani, which is a foramen in Kurmademys.</p> <p>PREARTICULAR</p> <p>Preservation: The prearticular is nearly complete on the left side of BSP 1976 I 160; the right one has some damage anteriorly. In THUg 1798 the prearticular is present on both sides; the left one is more complete than the right one.</p> <p>Contacts: The prearticular in Cearachelys contacts the coronoid anterolaterally and the articular posteriorly. The angular contact runs for nearly the entire length of the prearticular, as in Kurmademys and Euraxemys, but in contrast to the much shorter contact of Bothremydini and Taphrosphyini.</p> <p>Structures: The prearticular is a flat bone that forms the medial wall of the fossa meckelii, enclosing it for the entire length of the bone, in contrast to the more open fossa of Bothremydini and Taphrosphyini. In the angular-prearticular suture is a small foramen, the foramen intermandibularis caudalis.</p> <p>TRIBE BOTHREMYDINI Foxemys mechinorum (figs. 235, 236)</p> <p>MATERIAL AVAILABLE: PAM 511B, lower jaws lacking articular ends, figured in</p> <p>Tong et al. (1998: figs. 7, 8); MC M2114, jaw lacking both articular ends; MC M2115, left ramus lacking articulation; MC M2116, left ramus lacking articulation; MC M2117, jaw lacking articular ends; MC M2118, nearly complete jaw, lacking left articular end, some cracks with displacement in symphysis.</p> <p>DENTARY</p> <p>Preservation: The six specimens all have most of the dentary preserved, although the preservation is best in MC M2118. In the four small jaws, MC M2114, MC M2115, MC M2116, and MC M2117, the dentary is either present only on one side or it is damaged. The largest jaw, PAM 511B, is complete on the right side but is missing the dorsal part of the left ramus. The best jaw, MC M2118, has a nearly perfect right ramus, but there is breakage with some displacement on the symphysis.</p> <p>Contacts: The dentary in Foxemys contacts the coronoid posterodorsally, with more of the dentary being exposed ventral to the coronoid than in Kurmademys but not as much as in Bothremys. The surangular contact posterolaterally is more extensive anteriorly in Foxemys than in Kurmademys, but not as extensive as in Bothremys. The dentary contacts the angular posteroventrally, as in the other bothremydids.</p> <p>Structures: The dentary is preserved in all six Foxemys jaws and it shows a size range, as measured from the symphysis to the processus coronoideus (see appendix 8), from 39 to 19 mm, presumably related to age. This increase in size is correlated with an increase in width of the triturating surface, so that the largest, PAM 511B, also has the relatively widest triturating surface. The width increase seems to be expressed in the lingual shelf in the smaller jaws. In the larger jaws, the labial edge is significantly swollen.</p> <p>The symphysis of Foxemys has the symphyseal concavity of Kurmademys, but the lingual ridge on each side stops short of forming an anterior margin for the concavity, as in Kurmademys. The concavity is a sloping surface from the labial ridge posteriorly to the end of the symphysis. The labial ridge is upturned slightly in Foxemys, as in Kurmademys, rather than being flat, as in Araiochelys and Bothremys. The symphysis thickness is parallel trough are unique to Foxemys. In PAM 511B (Tong et al., 1998: figs. 7, 8), the labial ridge is rounded, the trough is shallower and wider, and the lingual shelf is wider than in MC M2118.</p> <p>In lateral view, the lingual shelf is higher than the labial ridge, agreeing with Cearachelys, Kurmademys, and other Bothremydini. The foramen dentofaciale majus lies entirely in the dentary, just anterior to the surangular contact. The medial surface of the dentary has a sulcus cartilaginis meckelii that stops short of the symphysis, as in Kurmademys and Araiochelys.</p> <p>greater in Foxemys than in the other bothremydids.</p> <p>The labial ridge in Foxemys is an acute ridge with a slight upturn that decreases in height posteriorly. In Kurmademys, Cearachelys, Araiochelys, Bothremys, and Chedighaii, the labial ridge is the edge of a relatively flat triturating surface, but in Foxemys the ridge is distinct on the margin of a trough that runs parallel to the ridge. None of the other bothremydids has the trough seen in Foxemys. Medial to the trough there is a wide, lingual shelf beginning anteriorly just behind the symphysis and sloping dorsally to the processus coronoideus. This shelf might be considered a flattened and broadened lingual ridge. The medial edge of the lingual shelf has no distinct ridge. This raised lingual shelf and ANGULAR</p> <p>Preservation: A nearly complete angular is present only on the right side of MC M2118, with the anterior part remaining on the left side. PAM 511B also has the anterior parts of both angulars. Small parts of the angular are also in MC M2114, MC M2116, and MC M2117.</p> <p>Contacts: The angular in Foxemys is very similar to that in Bothremys maghrebiana. It contacts the dentary anteriorly, the prearticular dorsally, the surangular dorsolaterally, and, presumably, the articular posteriorly, although the articular sutures are fused in MC M2118, the only specimen with an articular. The angular in Foxemys lacks the long prearticular contact seen in Kurmademys and Cearachelys. This short contact in Foxemys is the same as in Bothremys and other Bothremydini and Rhothonemys.</p> <p>Structures: The angular forms the ventral margin of the sulcus cartilaginis meckelii and lower edge of the jaw. The fossa meckelii has the more open condition, seen in other Bothremydini, rather than the more closed fossa of Cearachelys and Kurmademys and other pleurodires. The suture between the angular and prearticular is not perfectly preserved in MC M2118, but there is a foramen intermandibularis caudalis.</p> <p>SURANGULAR</p> <p>Preservation: The surangular is nearly complete only on the right side of MC M2118, but the anterior part is present on the left side as well in PAM 511B and MC M2114.</p> <p>rower. The surangular thickening is extensive and forms an upper ventrolaterally sloping surface and a ventral, medially sloping surface with a low ridge between them, all unique to Foxemys, among bothremydids. There is a small foramen on the upper surface.</p> <p>Contacts: The surangular in Foxemys contacts the dentary anteriorly, the angular ventrally, the coronoid anterodorsally, and, presumably, the articular posteromedially, although the sutures are fused.</p> <p>Structures: The surangular lateral exposure in Foxemys is not as extensive as in other Bothremydini, but it is more extensive than in Kurmademys and Cearachelys. In those taxa the dentary-surangular contact is vertical beneath the processus coronoideus, while in Foxemys, the surangular sends a process anteriorly. The surangular forms the lateral wall of the fossa meckelii and the lateral margin of the upper opening to the fossa. In Foxemys, in contrast to other bothremydids, the surangular is very thick, and the upper opening is displaced medially and is nar- CORONOID</p> <p>Preservation: Both coronoids are nearly complete in MC M2118. The right one is present in PAM 511B, and the left one is present in MC M2114.</p> <p>Contacts: The coronoid contacts the dentary anteriorly and ventrally, the surangular posterolaterally, and the prearticular posteromedially. The surangular contact is narrow, as in Kurmademys, not wide, as in Bothremys.</p> <p>Structures: The coronoid in Foxemys forms the posteromedial part of the triturating surface, in particular, the posterior part of the lingual shelf, ending just medial to the triturating surface trough. The posterior edge of the triturating surface is a ridge running just anterior to the very low processus coronoideus; the ridge is actually higher than the processus in lateral view. In Bothremys, there is no ridge at the edge of the triturating surface and the processus coronoideus is much higher. In Kurmademys and Cearachelys the morphology is more similar to that of Foxemys, but the processus is higher and not as distinct from the triturating surface ridge. The coronoid narrowly enters the margin of the upper opening of the fossa meckelii, as in other bothremydids.</p> <p>ARTICULAR</p> <p>Preservation: The articular is present only on the right side of MC M2118.</p> <p>Contacts: Sutures are fused in the available jaw.</p> <p>Structures: The area articularis mandibularis of Foxemys is roughly spherical, with the two facets separated by a low, parasagittal ridge seen in other bothremydids. The processus retroarticularis is short and broad, as in Cearachelys, broader than in Rhothonemys and much broader and shorter than in Bothremys maghrebiana. The foramen posterius chorda tympani is either a true foramen or a notch lateral to the processus retroarticularis; breakage prevents being sure which is the case.</p> <p>PREARTICULAR</p> <p>Preservation: A nearly complete prearticular is present only on the right side of MC M2118; the anterior part of the bone is on the left ramus.</p> <p>Contacts: The prearticular in Foxemys contacts the coronoid anterodorsally and the articular posteriorly, although no articular sutures are present. The ventral contact with the angular is only at the posterior end of the prearticular, as in the other Bothremydini and Rhothonemys. This is in contrast to the longer contact seen in Cearachelys and Kurmademys.</p> <p>Structures: The prearticular in Foxemys is very similar to that bone in Bothremys and Araiochelys. In these taxa the prearticular exposes the anteroventral part of the fossa meckelii, in contrast to Cearachelys and Kurmademys, which have the fossa covered by the prearticular. Nonetheless, the Foxemys prearticular is slightly larger than in B. maghrebiana and has a small foramen anterodorsally near the foramen alveolare inferius. However, the foramen intermandibularis caudalis is also present, as in Cearachelys and Kurmademys and in contrast to other Bothremydini.</p> <p>Araiochelys hirayamai (figs. 237, 238)</p> <p>MATERIAL AVAILABLE: THUg 3338, a nearly complete lower jaw.</p> <p>DENTARY</p> <p>Preservation: A complete dentary is present.</p> <p>Contacts: As in Bothremys maghrebiana.</p> <p>Structures: The dentary in Araiochelys is closest in morphology to that in Bothremys maghrebiana, among the known lower jaws. There is a well-developed pit formed medially by a high lingual ridge and laterally by the labial ridge. The pit and the entire jaw ramus are narrower than in B. maghrebiana, or any other Bothremydini, by at least one-half. The relative height of the lingual ridge and the thickness of both ridges are comparable to those in B. maghrebiana, so Araiochelys is not simply a less ossified version of B. maghrebiana. The horizontal part of the triturating surface is a curved trough in Araiochelys, not flat, as in B. maghrebiana and B. cooki. The symphyseal wedge, low in B. maghrebiana, is much thinner in Araiochelys, although its extent on the symphysis is the same. Due to the narrower triturating surfaces in Araiochelys, the area posterior to the lingual ridges along the front of the symphyseal groove is wider than in B. maghrebiana. On the posterior and medial surface of the dentary, the sulcus cartilaginis meckelii does not meet on the midline as it does in B. maghrebiana.</p> <p>ANGULAR</p> <p>Preservation: Both angulars are present and nearly complete.</p> <p>Contacts: As in Bothremys maghrebiana. The posterior sutures of the angular, articular, and surangular are unclear, however.</p> <p>Structures: The angular in Araiochelys is similar to that bone in B. maghrebiana.</p> <p>SURANGULAR</p> <p>Preservation: The surangular is complete on both sides, although the sutures are not entirely clear on the right side.</p> <p>Structures: The articular in Araiochelys is very similar to that in B. maghrebiana.</p> <p>PREARTICULAR</p> <p>Preservation: Both prearticulars in TH- Ug 3338 are present but have some damage to their medial surfaces.</p> <p>Contacts: As in B. maghrebiana.</p> <p>Structures: The prearticular in Araiochelys is very similar to that in B. maghrebiana.</p> <p>Bothremys cooki (fig. 239) MATERIAL AVAILABLE: AMNH 2521, a lower jaw lacking the posterior ends, part of type of Bothremys cooki Leidy, 1865 (pl. 18, figs. 5, 8), described in Hay (1908: fig. 97, pl. 23, fig. 3) and in Gaffney and Zangerl (1968: fig. 22).</p> <p>Structures: The surangular of Araiochelys is similar to that bone in Bothremys maghrebiana. The extent of surangular lying on the lateral side of the processus retroarticularis in Araiochelys is less than that in B. maghrebiana.</p> <p>CORONOID</p> <p>Preservation: Both coronoids are complete, although the right one is slightly damaged in THUg 3338.</p> <p>Contacts: As in Bothremys maghrebiana.</p> <p>Structures: The coronoid in Araiochelys is very similar to that in B. maghrebiana.</p> <p>ARTICULAR</p> <p>Preservation: The left articular is complete; the right one is missing some of the processus retroarticularis.</p> <p>Contacts: As in Bothremys maghrebiana.</p> <p>DENTARY</p> <p>Preservation: The dentary and other bones of the lower jaw in AMNH 2521 are pitted and covered in places with a thin layer of plaster, presumably applied in the days of Leidy as a preservative. Both in 1966 and at the present the senior author has been unable to find any damn sutures. However, there are some cracks on the ventral surface and below the processus coronoideus in the right place for sutures. The right dentary has some pitting near the symphysis and the labial edge, and the left one has cracks and some lateral pits. The symphyseal damage is on the surface; the original morphology does not appear to have been affected significantly. On the ventral surface, the pitting is deeper and more extensive, particularly on the right side.</p> <p>Contacts: Sutures are not visible.</p> <p>Structures: The jaw in Bothremys cooki is most similar to the jaw of B. maghrebiana. The high lingual ridge and rising labial ridge forming the large cone-shaped pit are very similar. The extent that the pit extends posteriorly under the coronoid is the same. Where the labial and lingual ridges form the edges of the pit, they are slightly more flared in B. cooki than in B. maghrebiana.</p> <p>The only prominent difference between the two jaws is in the symphyseal area. In B. cooki the lingual ridge is low and not defined anteriorly because of a thick wedge of bone medially. In B. maghrebiana, the lingual ridge is clearly defined, meeting on the midline the jaw in B. cooki ends in an obtuse angle with a terminal point, different from the rounded jaw margin in other Bothremydini. This point seems to be original; there is no evidence that it is a postmortem preservational or preparational artifact.</p> <p>On the medial surface of the dentary, the sulcus cartilaginis meckelii does not appear to extend to the symphysis and join, as in B. maghrebiana. The sulcus is not well preserved, but the foramen alveolare inferius is visible on both sides.</p> <p>ANGULAR</p> <p>Preservation: The anterior part of the angular is present on both sides in Bothremys cooki, although much of this area is covered by plaster or is missing on the left side.</p> <p>Contacts: Except for a suspicious crack on the ventral surface of the right ramus, there are no visible sutures for the angular.</p> <p>Structures: The angular in Bothremys cooki forms the ventral margin of the sulcus cartilaginis meckelii and is similar to that area in B. maghrebiana.</p> <p>SURANGULAR</p> <p>Preservation: The anterior part of the surangular is present on both sides in Bothremys cooki, although the left side is more damaged and has a layer of plaster on it.</p> <p>Contacts: Sutures are not visible.</p> <p>Structures: The surangular in Bothremys cooki forms the lateral margin of the fossa meckelii. The anterior part of the dorsal opening of the fossa is visible on both sides in B. cooki. The area of the bone is very similar to that in B. maghrebiana.</p> <p>anteriorly to define a posteromedial concavity, absent in B. cooki. This symphyseal wedge also occurs in UA 8708, a partial lower jaw from Madagascar (fig. 247; see also Gaffney and Forster, 2003). The anterior margin of CORONOID</p> <p>Preservation: Most of both coronoids seem to be present in Bothremys cooki. The processus coronoideus is broken on the left side and damaged medially on the right.</p> <p>Structures: The processus coronoideus of Bothremys cooki is higher and narrower in lateral view than in B. maghrebiana, Chedighaii, and Araiochelys. None of the bothremydid jaws, including AMNH 29989, has a high processus coronoideus.</p> <p>ARTICULAR</p> <p>Preservation: The articular is missing in AMNH 2521.</p> <p>PREARTICULAR</p> <p>Preservation: The anterior part of both prearticulars is present in Bothremys cooki; the right one has more bone, however.</p> <p>Contacts: Sutures are not visible.</p> <p>Structures: As in Bothremys maghrebiana, the prearticular of B. cooki shows an anteriorly open fossa meckelii, although the area is not well preserved.</p> <p>Bothremys maghrebiana (figs. 240, 241)</p> <p>MATERIAL AVAILABLE: AMNH 30522, right ramus and symphysis nearly complete, left ramus lacking labial ridge and processus retroarticularis.</p> <p>DENTARY</p> <p>Preservation: The dentary in AMNH 30522 is nearly complete on the right side, missing only the tip of the symphysis. On the left side the lateral one-third of the dentary is missing from the symphysis to the coronoid.</p> <p>Contacts: The dentary in Bothremys maghrebiana contacts the coronoid posterodorsally via broad sutures both medially and laterally where the two elements join in the formation of a deep pit. It contacts the surangular posterolaterally in a relatively short vertical suture ventral to the coronoid and a long horizontal ventral suture where the dentary extends posteriorly between the surangular and the angular. The dentary contacts the angular posteroventrally along a long suture. A narrow surangular contact with the dentary in Bothremys maghrebiana is visible in the medial wall of the sulcus cartilaginis meckelii.</p> <p>Structures: As in all Bothremydidae, the two rami of the dentary in Bothremys maghrebiana are fused in a long symphysis with no evidence of a suture. Dorsally, the posterior extent of the dentary is limited by the coronoid on the triturating surface; the coronoid makes up the posterior part of this surface. Ventrally, the dentary extends far more posteriorly, between the surangular and angular. It reaches posteriorly to the level of the anterior edge of the area articularis mandibularis. Within the sulcus cartilaginis meckelii the dentary can be seen to extend posteriorly below the fossa meckelii.</p> <p>The labial ridge of the dentary in Bothremys maghrebiana is an anteriorly facing horizontal ridge, except where it rises vertically at its posterior end to the coronoid process. This very low anterior edge gives the jaw an open, plowlike profile. The lingual ridge is high adjacent to the coronoid, but becomes lower anteriorly as it approaches the symphysis. The two lingual ridges meet in a narrow but well-defined U-shaped ridge that opens posteriorly. This U-shaped structure extends anteriorly nearly to the tip of the symphysis. The symphysis in Bothremys maghrebiana is deeply concave between the lingual ridges, forming a moderately thick symphyseal wedge, thicker than in Araiochelys.</p> <p>The large pits are the most obvious feature of the lower jaws, with the whole anterior half of the jaw being involved in their formation. The triturating pit in Bothremys has been described and commented on by Leidy (1865), Baur (1891), Hay (1908), and Gaffney and Zangerl (1968). The pit is formed mostly by the dentary. There is no distinct labial ridge anteriorly; the surface is essentially horizontal. Posteriorly the labial margin curves upward and forms the lateral side of the conical-shaped pit. The lingual ridge extends posteriorly and dorsally, forming the medial edge of the pit. The coronoid bridges the two ridges and forms most of the roof of the pit. The pit in Bothremys maghrebiana is very similar to that in B. cooki. The pit in Araiochelys is much narrower and occupies relatively less of the triturating surface. However, the lower jaw of AMNH 29989, unassociated with a skull, is a massive expression of the morphology seen in Bothremys. The lower jaws of Chedighaii have pits similar to Bothremys, and the species barberi was placed in Bothremys by Gaffney and Zangerl (1968) on the basis of the lower jaw pits.</p> <p>The anterior tip of the symphysis in B. maghrebiana is missing, but enough is preserved to show that a symphyseal hook was absent. In posterior view the dentary can be seen to have an open sulcus cartilaginis meckelii that remains open throughout its length to the symphysis, in contrast to Chedighaii and Araiochelys.</p> <p>The foramen intermandibularis medius and foramen alveolare inferius are not defined by bone, apparently because the sulcus foramina suggest that it extended posteriorly over the dentary pit and at least to the anterior edge of the coronoid. The coronoid makes up the entire dorsal quarter of the dentary pit and all of the coronoid process. Therefore, it seems unlikely that the dentary itself served as a site of insertion of the jaw adductor musculature.</p> <p>Although the dentary of Bothremys maghrebiana is similar to that of the type of the genus, B. cooki, the most apparent difference is the U-shaped area formed by the lingual ridges meeting on the symphysis, the symphyseal wedge. In B. cooki the symphyseal wedge is much thicker than in B. maghrebiana, which has an excavated concavity between the ridges rather than bone that is as high as the lingual ridges as in B. cooki. The dentary of B. maghrebiana differs further from other bothremydids in having a sulcus cartilaginis meckelii that is open to the symphysis. In other bothremydids this sulcus closes posterior to the symphysis.</p> <p>cartilaginis meckelii is widely open between the coronoid and prearticular dorsally and the angular ventrally. A well-developed foramen dentofaciale majus is visible on the right dentary in Bothremys maghrebiana, ventral to the labial ridge at a point just anterior to the sutures of the surangular and coronoid.</p> <p>The limits of the rhamphotheca are difficult to determine on this specimen of Bothremys maghrebiana. Enlarged nutritive ANGULAR</p> <p>Preservation: The angular of Bothremys maghrebiana is completely preserved and undistorted on the right side of the lower jaw. On the left side it is nearly complete, missing only the portion that makes up the retroarticular process.</p> <p>Contacts: The angular in Bothremys maghrebiana contacts the dentary all along its medial surface. Ventrally there is a long diagonal suture between these elements that extends from below the anterior edge of the area articularis mandibularis nearly to the symphysis. A dorsal suture between these elements marks the ventral limit of the sulcus cartilaginis meckelii. The angular forms a suture with the prearticular dorsally. This suture is horizontal just posterior to the closure of the sulcus cartilaginis meckelii, but it turns vertically on the medial surface of the area articularis where it contacts the articular. The angular meets the surangular posteroventrally in a long suture that extends from below the anterior edge of the area articularis to the posterior end of the long retroarticular process. This suture continues dorsally and then anteriorly to the posterior edge of the articular.</p> <p>meckelii in Bothremys maghrebiana. Howev- er, since this sulcus is widely open, neither the foramen intermandibularis caudalis nor the foramen intermandibularis oralis is defined by bone. Posterior to the sulcus this element expands medially to support the medial side of the articular. The angular extends posteriorly along the ventral margin of the processus retroarticularis. The angular of Bothremys maghrebiana is nearly identical to the anterior portion of this element that is preserved in B. cooki. The angular is slightly thicker in B. cooki and contacts the prearticular more anteriorly. The posterior parts of the jaw of B. cooki are not preserved.</p> <p>Structures: The angular forms most of the ventral margin of the sulcus cartilaginis</p> <p>SURANGULAR</p> <p>Preservation: The surangular of Bothremys maghrebiana is complete on the right side and nearly so on the left. On the left side only the portion posterior to the area articularis is missing.</p> <p>Contacts: The surangular of Bothremys maghrebiana has a short anterior contact with the dentary just posterior to the foramen dentofaciale majus. It also has a long ventral suture with the dentary that extends posteriorly to a point below the anterior edge of the area articularis mandibularis. It has an anterodorsal suture with the coronoid that extends from near the foramen dentofaciale majus to the fossa meckelii. The surangular meets the angular posteroventrally where these elements join to form the ventral margin of the processus retroarticularis. Posteromedially the surangular meets the articular, also on the processus retroarticularis.</p> <p>Structures: The surangular of Bothremys maghrebiana forms the lateral wall of the fossa meckelii. There is no foramen nervi auriculotemporalis visible on the lateral surface of this element. The foramen nervi auriculotemporalis is absent in Bothremydini and Taphrosphyini, but it is present in Cearachelys and Kurmademys, as well as pelomedusids, Araripemys, euraxemydids, and chelids. The surangular does not contribute directly to the area articularis mandibularis, but it supports the articular laterally. It also lies on the lateral wall of the processus retroarticularis, but it does not contribute significantly to this structure.</p> <p>The surangular in Bothremys maghrebiana is a relatively large bone, extending anteriorly below the coronoid and below the processus coronoideus. This is also the case in the other Bothremydini and Rhothonemys, one of the Taphrosphyini. In Kurmademys and Cearachelys, the surangular is more extensive anteriorly than in Euraxemys and pelomedusids, but not to the degree seen in Bothremydini and Taphrosphyini. In Cearachelys, Kurmademys, chelids, pelomedusids, Araripemys, Euraxemys, and podocnemidids, the dentary extends posteriorly on the lateral surface of the jaw to separate the surangular and angular. In Bothremydini and Taphrosphyini the dentary is less extensive and more restricted to the ventral surface.</p> <p>CORONOID</p> <p>Preservation: The coronoid of Bothremys maghrebiana is completely preserved on the right side but is missing the anterolateral part that articulates with the lingual ridge of the dentary on the left side.</p> <p>Contacts: The coronoid in Bothremys maghrebiana contacts the dentary anteriorly where it forms the dorsal part of the triturating pit. It broadly contacts the dentary both on the lingual ridge medially and on the labial ridge laterally. It contacts the surangular posterolaterally from just posterior to the foramen dentofaciale majus to the anterior end of the fossa meckelii. It also contacts the prearticular posteromedially between the fossa meckelii and the sulcus cartilaginis meckelii.</p> <p>Structures: The coronoid in Bothremys maghrebiana forms all of the low, rounded processus coronoideus. It also forms a narrow part of the anterior end of the fossa meckelii between the surangular and the prearticular, and it contributes significantly to the mandibular triturating surface by forming the overhanging, posterodorsal one-third of the large, deep pit.</p> <p>The coronoid of Bothremys maghrebiana is smaller than that in B. cooki. The coronoid extends farther anteroventrally in B. maghrebiana, but it has a very much lower coronoid process. It is more similar in size, height, and contacts to the coronoid of Araiochelys. The coronoid of Foxemys is smaller and lower than that in Bothremys and Araiochelys.</p> <p>ARTICULAR</p> <p>Preservation: The articular of Bothremys maghrebiana is completely preserved on the right side of the jaw, but it is missing its lateral half on the left side.</p> <p>Contacts: The articular contacts the surangular laterally between the fossa meckelii and the processus retroarticularis. It contacts the angular medially and ventrally and the prearticular anteromedially. It is not possible to see any contact between the articular and the dentary.</p> <p>Structures: The articular of Bothremys maghrebiana forms all of the area articularis mandibularis. The area is nearly round, being convex dorsally with an anteroposterior ridge in the middle. The articular also forms the posterior part of the fossa meckelii between the surangular and prearticular. It forms nearly all of the processus retroarticularis. A small foramen posterius chorda tympani is visible on the posterior suture between the articular and angular at the anterior end of the processus retroarticularis.</p> <p>The area articularis mandibularis of Bothremys maghrebiana can be compared to only a few other bothremydids that have this element preserved. It is round in Chedighaii barberi (FMNH PR 247, the type) and Araiochelys, as well as in B. maghrebiana. In Rhothonemys the area articularis mandibularis is oval-shaped, with the long axis of the oval being oriented about 45 ° medial to the midline.</p> <p>The processus retroarticularis in Bothremys maghrebiana is formed almost entirely by the articular, with a narrow layer of the angular on the ventral surface. The processus is long in B. maghrebiana, about as long as in Araiochelys. Both have a shallow concavity on the dorsal surface. In Rhothonemys the processus retroarticularis is shorter and broader, similar to that in Cearachelys and Kurmademys. In chelids, pelomedusids, Euraxemys, and Araripemys, the processus is very short or absent. Chedighaii barberi is not well preserved, but it has a large, broad processus, similar to that in Rhothonemys.</p> <p>PREARTICULAR</p> <p>Preservation: The prearticular of Bothremys maghrebiana is well preserved and complete on both sides.</p> <p>Contacts: The prearticular contacts the coronoid anteromedially, the articular posteromedially, and the angular posteroventrally.</p> <p>Structures: The prearticular in Bothremys maghrebiana forms the medial wall of the fossa meckelii and the posterodorsal limits of the sulcus cartilaginis meckelii and the foramen intermandibularis medius. The sulcus is widely open and, as in the other Bothremydini and Taphrosphyini, the foramen intermandibularis oralis and foramen intermandibularis caudalis are not defined by bone. The prearticular of Bothremys maghrebiana is comparable to that of Araiochelys and B. cooki insofar as the latter is preserved. In these forms the extent of contact between the prearticular and angular is reduced relative to that seen in Araripemys, Kurmademys, and Cearachelys. This contact is reduced to the point that the sulcus cartilaginis meckelii closes below the fossa meckelii; in the latter genera the sulcus cartilaginis meckelii closes below the coronoid process.</p> <p>SPLENIAL</p> <p>Preservation: The anteromedial part of the mandible of Bothremys maghrebiana is very well preserved and complete on both sides. It can be said confidently that it does not have a splenial.</p> <p>Chedighaii barberi (figs. 242–244)</p> <p>(See Note Added in Proof) MATERIAL AVAILABLE: FMNH PR 247, complete lower jaws (fig. 242) with badly eroded surface and some edges missing, associated with partial skull and shell, jaw described and figured in Gaffney and Zangerl (1968: fig. 22); ALAB PV 2001.2, right ramus missing symphysis and posterior end, left ramus missing posterior end and part of lingual ridge (figs. 242–244), associated with skull and partial shell; CSU K-90-6-2, jaw symphysis; NJSM 12704, cast (Denton Collection) of damaged right ramus.</p> <p>DENTARY</p> <p>Preservation: Only the symphysis and the anterior part of the right ramus are preserved in CSU K-90-6-2. The bone surface is only slightly eroded and cracked; most of it seems to be the original surface. In FMNH PR 247 the dentary is nearly complete, lacking the anterior end, but almost the entire bone surface has been eroded. The left dentary of ALAB 2001.2 is missing the midline, the anterior part of the lingual ridge, and a small part of its posterior end, but the bone surface is well preserved. In the right ramus, the entire anterior half is missing, as is the posterior end, but the remainder is well preserved.</p> <p>Contacts: Sutures are clear in ALAB 2001.2 and most are visible on one side or the other in FMNH PR 247. The dentary contacts in Chedighaii barberi are very similar to those in Bothremys maghrebiana.</p> <p>Structures: The dentary of Chedighaii barberi that can be seen in CSU K-90-6-2 and ALAB 2001.2 has an anterior, flat surface, which is the triturating surface, marked by many nutrient foramina, and a posterior, smooth surface, with a shallow concavity, the area of the symphyseal wedge. The concavity is defined anteriorly and laterally by the lingual ridge; posteriorly there is no margin. The symphysis in CSU K-90-6-2 is very similar to that in ALAB 2001.2, which is also flat anteriorly with a posterior concavity. The anterior margin seems slightly more acute in ALAB 2001.2, but it is not complete, so this may be misleading. The triturating surface on the symphysis is slightly wider anteroposteriorly in CSU K-90-6-2 than in ALAB 2001.2. In both the area is about half the length of the concavity behind it.</p> <p>The labial ridge in Chedighaii barberi is very low anteriorly, but the lingual ridge shows a dorsal rise, as in Bothremys cooki and B. maghrebiana. The symphyseal concavity in all the Chedighaii jaws does not form the thickened symphyseal wedge seen in B. cooki, and, to a lesser extent, B. maghrebiana. FMNH PR 247 seems to differ from CSU K-90-6-2 and ALAB 2001.2 in lacking a midline union of the lingual ridges, but most of this jaw is worn by abrasion (the anterior part particularly), and the anterior lingual ridges are very low, probably due to postmortem damage.</p> <p>On the ventral surface of CSU K-90-6-2, the nutrient-rich area covered by the horny beak is differentiated from the smooth posterior surface by a very low ridge that thickens laterally. The same ridge is in ALAB 2001.2, but FMNH PR 247 seems to be smooth, although this may be due to damage, as the surface is clearly eroded. Bothremys cooki and B. maghrebiana do not have this ridge where the foramina-rich surface changes to a smooth surface. On the medial surface of the symphysis in Chedighaii barberi, the anteriormost part of the sulcus meckelii extends close to the symphyseal area, but it does not meet the other sulcus on the midline, as in Bothremys maghrebiana.</p> <p>Posteriorly, the lingual ridge in Chedighaii barberi rises to form the medial wall of the triturating pit, as in Bothremys. The labial ridge is only the thickened margin of the triturating surface as it extends posteriorly, until it rises abruptly to form the lateral wall of the pit, as in B. maghrebiana as well. In FMNH PR 247 the ridges and pit are very similar to B. maghrebiana except for a greater thickness of the bone. In ALAB 2001.2, however, the lingual ridge wall is much thicker than the labial ridge wall and the pit is not as deep as in FMNH PR 247, which has the pit wall equal in thickness. The jaw width is narrower in ALAB 2001.2 than it is in FMNH PR 247. It seems best to attribute these differences to individual variation at present, in the absence of better material. NJSM 12704 is more like FMNH PR 247, but it has also been damaged by postmortem erosion. Thus, it is possible to characterize FMNH PR 247 and NJSM 12704 as having slightly wider jaws, deeper pits, and a poorly defined symphyseal concavity due to low lingual ridges, in contrast to ALAB 2001.2 and CSU K-90-6-2. It is possible that these differences represent different taxa. The incomplete nature of the specimens and the lack of supporting characters make recognizing two taxa dubious at present, and all these jaws are identified as Chedighaii barberi. Nonetheless, it should be kept in mind that ALAB 2001.2, the specimen with the narrower jaws and shallower pits, has a skull lacking pits and is the basis for moving the species barberi from Bothremys to Chedighaii. If FMNH PR 247 proves to be a jaw type that is found with a pitted skull in the future, uh oh, a change is in the wind.</p> <p>ANGULAR</p> <p>Preservation: Both FMNH PR 247 and ALAB 2001.2 have the angular preserved, although it is damaged on both sides. In FMNH PR 247 the bone is nearly complete but damaged on its surface.</p> <p>Contacts: The angular contacts in Chedighaii barberi are very similar to those in Bothremys maghrebiana. The prearticular is missing in both Chedighaii specimens, however, and the articular-angular suture appears fused, as is often the case in pleurodire jaws.</p> <p>Structures: The angular in Chedighaii is very similar to that bone in B. maghrebiana. SURANGULAR</p> <p>Preservation: The anterior part of the surangular is present on both sides of ALAB 2001.2. Both surangulars are nearly complete in FMNH PR 247, but they are eroded on their surfaces.</p> <p>Contacts: As in Bothremys maghrebiana. The articular suture is not discernable.</p> <p>Structures: The foramen dentofaciale majus in Chedighaii barberi is in the surangular-dentary suture in ALAB 2001.2, but it seems to be in the dentary in FMNH PR 247, although poor preservation makes it hard to be sure. In Bothremys maghrebiana the foramen is well onto the dentary. The surangular forms the lateral wall of the fossa meckelii, which in shape and size seem to be very similar to B. maghrebiana. The surangular thickness, however, is much greater in C. barberi than it is in B. maghrebiana and Araiochelys. This is determinable only in FMNH PR 247. The lateral wall drops straight ventrally in B. maghrebiana, but in C. barberi the surangular is thicker dorsally than ventrally. B. cooki appears to agree with C. barberi in this, although the area is not well preserved.</p> <p>CORONOID</p> <p>Preservation: The coronoid is preserved on both sides in FMNH PR 247 and ALAB 2001.2.</p> <p>Contacts: The coronoid of Chedighaii barberi differs slightly from Bothremys maghrebiana in having less lateral exposure. The prearticular is missing in all specimens, but the sutural surface shows its position to be very similar to that in B. maghrebiana. The dentary and surangular contacts are otherwise as in B. maghrebiana.</p> <p>Structures: The processus coronoideus in Chedighaii barberi is very similar to that in B. maghrebiana, not as high as in B. cooki. The coronoid forms the roof of the triturating pit in FMNH PR 247, as in Bothremys, with the dentary extending into the floor. In ALAB 2001.2, however, the shallower pit is formed almost entirely by the coronoid, and the dentary does not extend into the pit floor.</p> <p>ARTICULAR</p> <p>Preservation: The articular is preserved on both sides of FMNH PR 247, although it is somewhat eroded and no sutures defining it are visible.</p> <p>Contacts: In FMNH PR 247, sutures that define the articular are not visible, a common condition in turtles.</p> <p>Structures: The area articularis mandibularis in Chedighaii barberi is eroded and pitted, but it appears to be the same shape as in Bothremys maghrebiana, rounded with PREARTICULAR</p> <p>Preservation: The prearticular is absent in all Chedighaii barberi specimens, but the sutural contacts in FMNH PR 247 suggest a bone very similar to that in Bothremys maghrebiana.</p> <p>TRIBE BOTHREMYDINI</p> <p>Genus indeterminate</p> <p>MATERIAL AVAILABLE: AMNH 29989, lower jaw lacking posterior ends (figs. 245, 246), from the Ypresian Eocene Couche 1 phosphates of Ouled Abdoun, Morocco. This specimen cannot be physically fitted into the available skull material of Bothremys kellyi or other known taxa and probably represents an undescribed species.</p> <p>a low anteroposterior ridge. The processus retroarticularis seems to be complete on the left side. It is shorter, broader, and more massive than in B. maghrebiana, similar to the one in Rhothonemys.</p> <p>DENTARY</p> <p>Preservation: The dentary in AMNH 29989 is nearly complete.</p> <p>Contacts: The dentary in AMNH 29989 has similar contacts to those in Bothremys maghrebiana, but the coronoid contact is much smaller on the lateral jaw surface. Laterally, the dentary has a long, vertical suture with the surangular, restricting the coronoid contact dorsally.</p> <p>Structures: The paired pits and anteriorly open fossa meckelii in AMNH 29989 suggest a close relationship to the Bothremydini, but the massiveness and detailed triturating surface shape show that AMNH 29989 is a new taxon not represented by known cranial material.</p> <p>The triturating surface in AMNH 29989 has the pit formed by labial and lingual ridges. The pit is about the same relative size as in Bothremys, although it is higher than wide rather than equidimensional as in Bothremys. The lingual ridge that forms the medial wall of the pit is much thicker than it is in Bothremys. The anterior continuation of the lingual ridge curves laterally and meets the labial ridge rather than meeting on the symphysis as in B. maghrebiana and Araiochelys. The area between the lingual ridges forms a deep concavity with a low transverse ridge posteriorly and an upturned labial margin anteriorly. This concavity is the symphyseal wedge, which in other Bothremydini is not as deep and is bordered by the lingual ridges anteriorly. The symphysis in AMNH 29989 is much longer than in other bothremydids. It extends posteriorly to the level of the processus coronoideus, about twice the length of the symphysis in Bothremys.</p> <p>The ventral surface of the dentary in Bothremys is relatively flat, but in AMNH 29989 it is deep posteriorly, where the bone is very thick, and tapers anteriorly to the labial margin. The symphyseal ventral surface is deeper and convex rather than flat as in Bothremys. The sulcus cartilaginis meckelii is relatively broad in AMNH 29989, related to the much higher and more massive jaw, compared to Bothremys. The sulcus does not reach the symphysis, as in B. maghrebiana. The foramen alveolare inferius and the contact with the surangular can be seen on the lateral wall of the fossa meckelii.</p> <p>In contrast to other Bothremydini, AMNH 29989 has a highly vascularized triturating surface with nutrient foramina varying in size. The rhamphotheca-covered area does not have distinct margins, agreeing with other Bothremydini.</p> <p>The foramen dentofaciale majus is formed entirely by the dentary and is contained in a shallow depression on the lateral surface of the dentary. There are what appear to be at least two foramina leading into the canalis alveolaris inferior from this depression.</p> <p>ANGULAR</p> <p>Preservation: The anterior part of the angular is preserved on the right side in AMNH 29989; only a small part is preserved on the left one.</p> <p>Contacts: The angular in AMNH 29989 contacts the dentary in a short suture, rather than a long one as in Bothremys maghrebiana. The prearticular contact is more dorsal due to the greater height of AMNH 29989.</p> <p>Structures: The angular in AMNH 29989 is deeper and shorter than in Bothremys maghrebiana, but the restricted prearticular contact still results in a relatively open fossa meckelii.</p> <p>SURANGULAR</p> <p>Preservation: The surangular is present on both sides of AMNH 29989, but both lack their posterior portions, broken off behind the fossa meckelii.</p> <p>Contacts: The dentary contact is extensive and long, compared to Bothremys maghrebiana. The coronoid contact is much smaller than in B. maghrebiana.</p> <p>Structures: AMNH 29989 is a deep and short jaw compared to Bothremys, and the surangular and dentary form most of the surface in lateral view. The relations of the surangular, however, are the same as in B. maghrebiana: it forms the lateral wall and dorsal opening of the fossa meckelii.</p> <p>CORONOID</p> <p>Preservation: Both coronoids in AMNH 29989 are complete.</p> <p>Contacts: The coronoid in AMNH 29989 extends farther anteriorly along the lingual ridge and does not reach the labial ridge, in contrast to Bothremys. The medial exposure of the coronoid is less also because the dentary suture is placed more posteriorly. Laterally, the coronoid is much less extensive than in other Bothremydini because of the dorsal position of the dentary and surangular contacts.</p> <p>Structures: Despite its massive form, the processus coronoideus is slightly lower than in B. maghrebiana and much lower than in B. cooki.</p> <p>ARTICULAR</p> <p>Preservation: A small part of articular in AMNH 29989 is exposed as a broken edge on the right side; otherwise, the bone is missing.</p> <p>PREARTICULAR</p> <p>Preservation: Only the right prearticular is present in AMNH 29989, and it is missing its posterior margin.</p> <p>Contacts: The prearticular in AMNH 29989 contacts the coronoid anterodorsally and the angular posteroventrally.</p> <p>Structures: The prearticular in AMNH 29989 is a higher, shorter bone than it is in Bothremys, and it is thicker and more massive. It forms the medial wall of the fossa meckelii. The fossa is more open than in Euraxemys, pelomedusids, and chelids, agreeing with other Bothremydini and Taphrosphyini.</p> <p>TRIBE TAPHROSPHYINI Rhothonemys brinkmani (figs. 248, 249)</p> <p>MATERIAL AVAILABLE: AMNH 30521, lower jaw lacking coronoid areas and both prearticulars, associated with skull.</p> <p>DENTARY</p> <p>Preservation: Nearly all of the left dentary in AMNH 30521 is present; the right one lacks most of its posterior contacts and is separated from the posterior jaw elements without good contacts. A posteroventral piece of dentary is present in the right posterior jaw piece.</p> <p>Contacts: The dentary in Rhothonemys has only one piece of coronoid remaining; most of the coronoid attachment area is either broken or a sutural surface. The coronoid contact remaining is on the dorsomedial side of the dentary, just above and lateral to the fossa meckelii. Although incomplete, the coronoid contact in Rhothonemys appears to be less extensive medially and laterally compared to Bothremys maghrebiana; it seems to have been similar to that in Euraxemys. The surangular contact is more anterior than in Euraxemys and is similar to Bothremydini. In Rhothonemys this suture runs along the posterior edge of the foramina-rich surface for the rhamphotheca, in contrast to other Pelomedusoides. The angular contact is similar to Bothremydini as well. The prearticular is missing.</p> <p>Structures: The dentary in Rhothonemys is fused at the symphysis, as in all other bothremydids. The dentary does not extend posteriorly to the degree seen in Euraxemys; it is similar to other bothremydids. The lateral side shows the foramen dentofaciale majus as a large foramen formed by the dentary anteriorly and the surangular posteriorly. The foramina-rich lateral surface extends to the posterior edge of the dentary; the surangular-dentary suture marks the limits of the rhamphotheca. This is in contrast to other bothremydids in which the rhamphotheca ends anterior to the edge of the dentary. The nutrient canal-rich area does not extend onto the ventral surface of the dentary.</p> <p>The triturating surface in the lower jaw of Rhothonemys is very unusual for pleurodires in general and for bothremydids in particular. The dentary is roughly parallel-sided; it does not widen posterolaterally, and it is narrow. The triturating surface, as determined by foramen-rich bone and lingual and labial ridges, is very narrow, less than one-third the width of the dentary in dorsal view. The labial ridge is distinct and forms a low hook at the symphysis, but it nearly disappears posteriorly, becoming barely identifiable at the posterior edge of the dentary. The lingual ridge, very low at the symphysis, rises posteriorly so that it is the dorsalmost part of the jaw posterior to the symphysis. The lingual ridge is still blunt and low, and it barely rises above the level of the rest of the jaw. The triturating surface of Rhothonemys is very different from that in the Bothremydini. The surface is unusually narrow (rather than wide), it does not rise dorsally to a high processus coronoideus, and there is a symphyseal hook. The only similarity to Bothremydini is the lingual ridge that rises posteriorly to be dorsal to the labial ridge.</p> <p>A possible tribe Taphrosphyini lower jaw is described in Bardet et al. (2000: 281, fig. 7d, e) as a ‘‘Chelonioidea gen. and sp. indet’’. Associated with this jaw are shell elements also described and figured (Bardet et al., 2000: 281, fig.7a–c, g), one of which (fig. 7a) has the iliac scar small, round, and at the shell margin, features probably diagnostic for the tribe Taphrosphyini. The lower jaw is very similar to those of Rhothonemys and Taphrosphys congolensis (see figs. 248–250).</p> <p>The dentary surface medial to the lingual ridge in Rhothonemys is smooth and slopes ventromedially, with a slightly concave shape. This surface is about three times wider than the triturating surface itself. On the medial surface, the dentary forms the sulcus cartilaginis meckelii, which is a sharply defined, V-shaped trough similar to that in other bothremydids, but not meeting on the midline as in Bothremys maghrebiana. The foramen alveolare inferius in Rhothonemys lies near the posterior end of the dentary on the medial surface in the region where the fossa meckelii grades into the sulcus cartilaginis meckelii. It is exposed on the right side, but on the left it is behind the displaced fragment of coronoid. Presumably, it was originally visible in medial view.</p> <p>ANGULAR</p> <p>Preservation: Both angulars are present in AMNH 30521, but neither is complete. The right one is complete posteriorly but is missing its anterior third. The missing part can be determined from the matching sutural surface on the dentary. The left angular is more complete, but its anterior third is broken and slightly displaced from its dentary contact.</p> <p>Contacts: The anterior dentary contact in Rhothonemys is clear and similar to that in other bothremydids. It forms a V-shaped process of the angular lying below the sulcus cartilaginis meckelii. The prearticular is missing in AMNH 30521, but the angular and articular show a short, sutural contact for it, similar in position to that in the Bothremydini. The angular merges into the articular with no sign of a suture in AMNH 30521, as in many adult pleurodires. Posteroventrally, the angular in Rhothonemys has a long contact with the surangular, also as in other pleurodires.</p> <p>Structures: The angular in Rhothonemys is a splintlike element forming the ventromedial surface of the jaw, below the fossa meckelii and sulcus cartilaginis meckelii. In Rhothonemys the angular has a short contact with the prearticular dorsally, with a free edge exposing most of the ventral part of the fossa meckelii, all as in Bothremys maghrebiana and other Bothremydini and in contrast to other pleurodires. The angular in Rhothonemys curves dorsomedially to form the floor of the fossa meckelii. Because the fossa meckelii is relatively open anteriorly, the foramen intermandibularis medius is placed posteriorly and the foramen intermandibularis caudalis is not formed, all as in Bothremys maghrebiana.</p> <p>SURANGULAR</p> <p>Preservation: The left surangular in AMNH 30521 is nearly complete, lacking only some of the dorsal margin. The right surangular is less complete, lacking its anterior and anterodorsal margins.</p> <p>Contacts: The surangular in Rhothonemys contacts the dentary anteriorly, the angular posteroventrally, and the articular posteromedially. The coronoid is largely missing in AMNH 30521, and the surangular-coronoid contact surface is damaged.</p> <p>Structures: The surangular in Rhothonemys is a large, sheetlike element at the posterior end of the jaw, forming the lateral wall of the fossa meckelii. As preserved, the fossa is similar to that in Bothremys maghrebiana, but the dorsal opening of the fossa is not preserved, so its shape is indeterminate. Posteriorly the surangular lies lateral to the blocklike articular, and in Rhothonemys it barely extends onto the area articularis mandibularis. The surangular extends posteriorly onto part of the processus retroarticudentary, it indicates a posterodorsally sloping dentary contact in Rhothonemys, in contrast to the more vertical one of Bothremys maghrebiana.</p> <p>ARTICULAR</p> <p>Preservation: Both articulars are present and seem to be complete in Rhothonemys. Due to the fusion of some sutures, however, this is not certain.</p> <p>Contacts: The articular in Rhothonemys contacts the surangular laterally and is fused with the angular ventrally and anteroventrally. The prearticular is missing, but a sutural surface shows a medial contact, as in other pleurodires.</p> <p>Structures: The articular forms nearly all of the area articularis mandibularis in Rhothonemys. The surface is roughly divided into two facets by a very low anteroposterior ridge, as in Bothremys maghrebiana. The medial facet is larger and more anterior than the lateral one. In B. maghrebiana they are more equal in size.</p> <p>The articular in Rhothonemys forms nearly all of the processus retroarticularis; the angular contribution is uncertain due to sutural fusion. The processus is large in Rhothonemys, much larger than in Euraxemys and the Pelomedusidae. In Rhothonemys it is shorter, broader, and not concave dorsally, in contrast to Bothremys maghrebiana. There is no foramen posterius chorda tympani. The articular forms the posterior wall of the fossa meckelii.</p> <p>laris, as in other bothremydids. There is no foramen nervi auriculotemporalis.</p> <p>CORONOID</p> <p>Preservation: Only a fragment of the coronoid is present anteriorly on the medial surface of the left ramus in AMNH 30521. It is slightly displaced ventrally. Along with the contact area on the medial surface of the PREARTICULAR</p> <p>Preservation: The prearticular is missing in AMNH 30521, but a sutural surface on the articular and angular shows that one was present.</p> <p>EPIFAMILY PODOCNEMIDINURA</p> <p>Hamadachelys escuilliei MATERIAL AVAILABLE: AMNH 30029, left ramus (fig. 251), broken off approximately at or near the symphysis. This unassociated lower jaw is identified as Hamadachelys. Originally suspected to be the lower jaw of Galianemys, further preparation of Hamadachelys material shows that it belongs to this contemporary genus. We retain it for comparison with bothremydids.</p> <p>DENTARY</p> <p>Preservation: The left dentary in AMNH 30029 lacks the posterior ventral process and is preserved up to what seems to be the midline, although it is hard to be sure.</p> <p>Contacts: The dentary in AMNH 30029 contacts the coronoid posterodorsally, the surangular posteriorly, but more dorsally than in Cearachelys or Kurmademys, and the angular posteroventrally. The surangular contact is vertical dorsally, but it becomes horizontal midway in its height, rather than at the bottom edge.</p> <p>Structures: The symphyseal area as preserved in AMNH 30029 seems to be very similar to Kurmademys, particularly ISI 155D, which has a symphyseal hook. The hook is likely in AMNH 30029 because the labial ridge is rising at its broken edge. The narrow triturating surface, defined posteriorly by a Ushaped concavity with a low lingual ridge as its border, is very similar to this area in Cearachelys and Kurmademys. The labial ridge is slightly higher than the lingual ridge anteriorly, as in Cearachelys, THUg 1798. Also as in this Cearachelys specimen, the triturating surface is narrower than in Cearachelys, BSP 1976 I 160, and Kurmademys, although clearly there is variation in this in both Cearachelys and Kurmademys. The lingual ridge in AMNH 30029 rises posteriorly and is higher than the labial ridge, as in bothremydids. The triturating surface is slightly concave along its length, similar to that in Kurmademys and Cearachelys, except it is not as flat anteriorly. The jaw ramus is slightly deeper and more massive than in Cearachelys, similar to Kurmademys.</p> <p>The sulcus cartilaginis meckelii is similar to that in Kurmademys and Cearachelys. The foramen dentofaciale majus is at the upper edge of the ramus, in the processus coronoideus, rather than more ventrally, as in Kurmademys and Cearachelys.</p> <p>ANGULAR</p> <p>Preservation: The anterior half of the left angular is present in AMNH 30029.</p> <p>Contacts: The angular in AMNH 30029 contacts the prearticular dorsally and the dentary anteriorly and ventrally. The prearticular contact is long, as in Kurmademys and Cearachelys.</p> <p>Structures: The angular in AMNH 30029 borders the sulcus cartilaginis meckelii, as in Kurmademys and Cearachelys. The angular wraps ventrally around the jaw, as in other pleurodires.</p> <p>SURANGULAR</p> <p>Preservation: Only a small part of the surangular, just posterior to the processus coronoideus, is present in AMNH 30029.</p> <p>Contacts: The surangular in AMNH 30029 contacts the dentary anteriorly and dorsally and the coronoid anteromedially, as in Kurmademys and Cearachelys.</p> <p>Structures: The surangular forms the lateral wall and dorsal margin of the fossa meckelii, the anterior part of which is present in AMNH 30029. The dentary and surangular form the lateral side of the processus coronoideus. There is not enough of the surangular preserved to determine other features.</p> <p>CORONOID</p> <p>Preservation: All of the coronoid is present in AMNH 30029.</p> <p>Contacts: The coronoid in AMNH 30029 contacts the dentary anteriorly, the prearticular posteroventrally, and the surangular posteriorly.</p> <p>Structures: The processus coronoideus in AMNH 30029 is slightly lower than that in Kurmademys and Cearachelys, but its shape is still similar to that in those taxa. The coronoid forms part of the dorsal edge of the foramen intermandibularis medius. The coronoid does not extend onto the triturating surface to the extent seen in Kurmademys, but it does form part of the medial margin and lingual ridge as in Cearachelys.</p> <p>ARTICULAR</p> <p>Preservation: The articular is missing in AMNH 30029.</p> <p>PREARTICULAR</p> <p>Preservation: The anterior part of the prearticular is present in AMNH 30029.</p> <p>Contacts: The prearticular in AMNH 30029 contacts the coronoid dorsally and the angular ventrally. Other contacts are not preserved.</p> <p>Structures: The prearticular in AMNH 30029 has the anterior extent seen in Kurmademys and Cearachelys and is not short as in the Bothremydini and Taphrosphyini.</p> <p>SHELL MORPHOLOGY</p> <p>FAMILY EURAXEMYDIDAE</p> <p>Euraxemys essweini, n. gen. et sp.</p> <p>(figs. 252–254)</p> <p>MATERIAL AVAILABLE: FR 4922, a nearly complete shell. The shell of Euraxemys was originally in a concretion broken in half transversely (not into part and counterpart, the usual pattern for Santana fossils), and it was repaired with a solvent-based putty that also covered the ventral surface before being acquired by the Senkenburg Museum. This putty was removed at AMNH, the entire surface cleaned, and the rearticulated shell was embedded in a clear plastic that covered the carapace. Before embedding in plastic, a cast, AMNH 30568, was made of the carapace. With the ventral surface exposed, the shell was acid prepared using techniques described in Rutzky et al. (1994). The outline and margins of FR 4922 do not appear to be distorted, as the plastron and bridge have what seem to be their natural curvature. The central area of the carapace, however, is crushed ventrally with much of the bone broken. The original curvature is retained along the posterior margin. Due to the fragmented condition of the bone of the carapace, complete removal of the matrix was halted in order to leave a layer just beneath most of the carapace. Despite the breakage, many of the carapacial sutures are visible, but the scale sulci are largely obscured except along the well-preserved posterior margin. The anterior part of the ventral surface is visible in FR 4922, but the posterior area medial to the peripherals is covered by matrix.</p> <p>The published reconstruction of the shell (Gaffney and Meylan, 1991) is incorrect in a number of areas, and a new description is presented here (fig. 254).</p> <p>CARAPACE</p> <p>Shell surface texture is largely obscured by breakage in FR 4922, but the distal portion of left costals 1–3 has the surface preserved (particularly visible on the cast). The surface texture has the form of low ridges and troughs roughly parallel to the lateral margins of the pleural scales, a surface ornamentation commonly seen in cryptodires (cf. Ernst et al., 1994: pl. 24, Clemmys muhlenbergii) but not often in pleurodires. Nonetheless, it is a common chelonian pattern seemingly related to growth of the pleural scales.</p> <p>Although damaged, the nuchal bone can be restored because its right lateral and posterior limits are determinable. It has the common six-sided shape of most Pelomedusoides, such as Taphrosphys, but it does not have the slight nuchal embayment seen in Chedighaii or in the original reconstruction of FR 4922 (Gaffney and Meylan, 1991), which also shows the nuchal as too long. The first two peripheral bones can be made out on the left side of FR 4922, and they are very similar to most other Pelomedusoides, such as Taphrosphys. They differ significantly from Araripemys, which has greatly reduced the anterior peripherals and lost contact with the nuchal. The bridge peripherals in FR 4922 are damaged on the dorsal surface but are better preserved ventrally, particularly on the left side. The bridge peripherals do not have guttering, and there is no indication of fontanelles as in Araripemys. The posterior peripherals 8–11 and pygal are well preserved and show the original shell curvature.</p> <p>Peripheral 11 has an undercut separating the external and internal surfaces on the ventral side. The body wall margin separates these two surfaces. The internal surface is concave anteriorly and is nearly vertical. On the dorsal surface the pygal and posterior peripherals have a distinct flare that curves dorsally, suggesting that the shell may have been higher domed than in Cearachelys and was similar to the higher domed Pseudemys species. The crushing has greatly altered the original curvature.</p> <p>Euraxemys has eight pairs of costals, with 2–7 being parallel-sided. The first costal is expanded anteriorly, as in nearly all turtles, and the eighth costal is slightly expanded distally. Many of the costal sutures are indeterminate due to breakage, but some of their limits can be determined by assuming bilateral symmetry and restoring by transposition. Costals 3–5 are particularly poorly preserved because this is the region where the concretion containing the skeleton was broken in half transversely. None of the costals meets on the midline. The suprapygal is six-sided, contacting the eighth neural anteriorly, the eighth costals laterally, the eleventh peripherals in a narrow pair of contacts, and the pygal posteriorly. The pygal is four-sided and nearly square, as in many Pelomedusoides butin contrast to the long pygal of Araripemys and the short pygal of Notoemys.</p> <p>The neurals of Euraxemys are a complete set of eight with the common Pelomedusoides condition of 4, 6, 6, 6, 6, 6, 6, 6. Although many of the neurals are not well preserved, their shapes have been determined by reconstruction that assumes bilateral symmetry. The shortest neural is probably the seventh, with the eighth being about the length of the sixth. The first neural is the common shape seen in living Pelomedusoides, that is, rectangular with slightly curved margins. Neurals 2–5 are ‘‘coffinshaped’’ hexagonal: neural 6 is wide and short, neural 7 is wider than long, and neural 8 is similar in shape to neural 2 but smaller.</p> <p>The ventral surface of the carapace in FR 4922 shows some morphology, although the area largely consists of finely broken bone. The nuchal, peripherals 1–4, costal 1, and the first neural can all be made out. Although broken, the first thoracic centrum is preserved. The anterior articulation and zygapophyses are missing, but its ventral surface is flat. The first thoracic ribs are preserved and they extend sharply posterolaterally, as in pelomedusids. Distally they curve laterally and are longer than in pelomedusids. In pelomedusids and all other living pleurodires the ribs are relatively flat and more closely sutured to the first costal than in Euraxemys, which has ribs that are rounded and seem to be free of the costal for a greater length. The Euraxemys rib does not have the short anterior projection seen in Pelomedusa. The posterior contact with the second thoracic is a flat ankylosis, with the first costal rib contacting both the first and second thoracic centra as in all other pleurodires.</p> <p>The scale pattern on the carapace of Euraxemys is clear around the posterior edge but is not well preserved elsewhere. There does not seem to be a cervical scale, and there is the normal set of 12 marginals as in other Pelomedusoides. Marginals 1, 2, and 8–12 are determinable and lie entirely on the peripherals. The elongate marginal 2 of the Gaffney and Meylan (1991) reconstruction was in error. This marginal is similar in size to the first. The only vertebral scales that have margins preserved are the second and the fifth. The sulci for the second vertebral are visible laterally on the right and left sides where they cross the costal 1–2 suture and anteriorly where it crosses the neural 1. The second vertebral is similar in width to that in other Pelomedusoides such as Taphrosphys. The fifth vertebral is also similar to Taphrosphys but it may be slightly wider. The new reconstruction of FR 4922 indicates wider vertebrals than in the Gaffney and Meylan (1991) figure. The pleural scales are poorly preserved, and only the pleural 1–2, 3–4, and 4–5 sulci are preserved. There are no supramarginal scales as in Proterochersis and Platychelys.</p> <p>PLASTRON</p> <p>The plastron of Euraxemys is made up of the usual 11 bones found in most Pelomedusoides. The anterior lobe is shorter than the posterior lobe, but it reaches the anterior edge of the carapace, similar to that in Dortoka. The size and shape of the entoplastron, epiplastra, and anterior lobe in Gaffney and Meylan (1991) are incorrect (fig. 254). There is a relatively short midline contact of the epiplastra, as in most Pelomedusoides. The entoplastron of Euraxemys is quadrangular, as in most pleurodires. It is slightly longer than wide, in contrast to Chedighaii and Taphrosphys in which it is slightly wider than long. The hyoplastron forms the axillary notch. The hypoplastron forms the inguinal notch, which is relatively open. Neither notch is as open as in Araripemys, however.</p> <p>Euraxemys has paired, laterally placed mesoplastra, in contrast to Araripemys, Dortoka, and chelids, which lack them, and in common with all other Pelomedusoides. Although neither mesoplastron in FR 4922 is complete, their limits can be reconstructed. The mesoplastron is slightly larger than in such forms as Bothremys, Pelomedusa, and Podocnemis. The mesoplastron does not extend farther medially than in most Pelomedusoides. There are no fontanelles in the Euraxemys plastron, and there are no foramina for musk ducts visible.</p> <p>The xiphiplastron in Euraxemys forms most of the posterior lobe, which tapers posteriorly as in Platychelys and Notoemys and in contrast to forms like Taphrosphys, which are roughly parallel-sided. The posteriorly tapering plastron of Euraxemys is nearly the only similarity it has to that of Araripemys. There is a shallow anal notch, also similar to Araripemys and Platychelys and distinct from the deeper notch commonly seen in other Pelomedusoides.</p> <p>There is the common Pelomedusoides complement of 13 scales on the plastron of Euraxemys, with no indication of axillary, inguinal, or inframarginal scales. There is a large, parallel-sided, intergular overlapping onto the entoplastron completely separating the smaller gulars and partially separating the humerals. This is essentially the same pattern seen in Pelusios, Podocnemis, and bothremydids like Cearachelys, Foxemys, Chedighaii, and Polysternon, but distinct from forms like Taphrosphys, which has a larger intergular scale completely separating the humeral scales, and Pelomedusa, which has very large humerals only slightly separated by the intergular. The gular scales in Euraxemys lie entirely on the epiplastra and are triangular.</p> <p>The humeral scales are separated anteriorly by the gulars and intergular and are in contact medially for about half their length. The humeral scales extend onto the entoplastron. The humeral-pectoral sulcus is more posterior in Euraxemys than in forms like Bothremys, so that the humeral scale dominates the anterior lobe margin. The pectoral scales do not overlap onto the posterior half of the entoplastron, in contrast to the reconstruction of Gaffney and Meylan (1991). The pectoral-abdominal sulcus runs along the posterior part of the hyoplastra onto the mesoplastra. The abdominal and femoral scales in Euraxemys are similar to those in Cearachelys and most Pelomedusoides, as these scales do not exhibit much variation. The femoral-anal sulcus runs anteromedially rather than straight transversely in Euraxemys.</p> <p>FAMILY BOTHREMYDIDAE</p> <p>TRIBE KURMADEMYDINI Kurmademys kallamedensis (figs. 255–257) MATERIAL AVAILABLE: ISIR 278, partial shell; ISIR 152A, left costal 1; ISIR 152B, left costal 4; ISIR 152C, left costal 2; ISIR 152D, right hypoplastron; ISIR 152E, hyoplastron fragment; ISIR 152F, left ninth or tenth peripheral; ISIR 152G, left tenth or eleventh peripheral; ISIR 152H, costal fragment; ISIR 152I, nuchal; ISIR 152J, right costal 3; ISIR 152K, right peripheral 3; ISIR 152L, right peripheral 8; ISIR 152M, costal; ISIR 152N, bridge peripheral; ISIR 152O, right costal 1; ISIR 152Q, left hypoplastron; ISIR 152R, left hypoplastron; ISIR 152S, right hyoplastron; ISIR 152T, right peripheral 2; ISIR 153A, left costals 1 and 2, peripherals 3 and 4; ISIR 153B, neural 3; ISIR 153C, right costal 1; ISIR 153E, right costal 1; ISIR 153F, left peripheral 7; ISIR 153G, right costal 1; ISIR 153H, right xiphiplastron; ISIR 157B, right hyoplastron; ISIR 157D, costal fragment; ISIR 157E, left costal 1; ISIR 157F, costal fragment; ISIR 157G, right? eighth peripheral; ISIR 157H, costal; ISIR 157I, buttress or peripheral; ISIR 157J, buttress; ISIR 157K, buttress; ISIR 157L, right xiphiplastron; ISIR 157M, mesoplastron; ISIR 157P, costal 5; ISIR 157Q, costal 5; ISIR 157R, right costal 1; ISIR 157U, left costal 1; ISIR 157V, costal fragment; ISIR 157W, left costal 1; ISIR 157X, costal; ISIR 157Y, peripheral; ISIR 157Z, costal; ISIR 157AA, costal; ISIR 157AB, right hypoplastron; ISIR 157AC, neural 3 or 5?; ISIR 157AD, peripheral 9 or 10?; ISIR 157AE, neural 3 or 5?; ISIR 157AF, peripheral 2; ISIR 157AG, bridge peripheral; ISIR 157AH, neural; ISIR 157AJ, neural; ISIR 157AK, peripheral; ISIR 157AL, costal; ISIR 157AM, peripheral; ISIR 157AN, costal; ISIR 157AO, left xiphiplastron; ISIR 157AP, left peripheral 6; ISIR 157AQ, left hypoplastron; ISIR 157 AS, costal 5; ISIR 157AT, bridge peripheral; ISIR 157AU, right costal 1; ISIR 157AV, costal 5; ISIR 157AW, peripheral 8; ISIR 157AX, neural; ISIR 157AY, neural; ISIR 157AZ, right costal 5; ISIR 157BA, right costal 7; ISIR 157BB, first neural; ISIR 157BC, fourth neural; ISIR 157BD, second neural; ISIR 157BE, nuchal; ISIR 157BH, left costal 5; ISIR 157BI, right peripheral 2; ISIR 157BJ, left costal 1; ISIR 157BK, right hypoplastron; ISIR 157BL, neural; ISIR 157BM, right costal 1; ISIR 157BN, left costal 5; ISIR 157BO, right xiphiplastron; ISIR 157BS, costal; ISIR 157BT, costal 1; ISIR 157BU, costal.</p> <p>CARAPACE</p> <p>The shell of Kurmademys has not previously been illustrated. The carapace is incomplete in ISIR 278; the anterior part is damaged. The reconstruction is also based on ISIR 157BE (nuchal), ISIR 157W (costal 1), ISIR 152T (peripheral 2), and ISIR 152K (peripheral 3). The carapace is oval in shape and apparently lower than in most bothremydids, although crushing may obscure its original depth. The shell surface shows the ‘‘pelomedusoid’’ pattern to some extent (Broin, 1977), at least on the bridge region.</p> <p>The carapace consists of one nuchal, six neurals, one suprapygal, one pygal, eight pairs of costals, and 11pairs of peripherals, although the first peripheral is not known. The nuchal is pentagonal in shape without nuchal emargination, and it is wider than long as in Chedighaii. The first neural is more elongated than the following neurals and is roughly rectangular in shape. It does not contact the second costal, as in most bothremydids. The second to fifth neurals are all elongated and six-sided with the short anterolateral sides. The sixth neural is five-sided and as long as wide; it does not contact the suprapygal. The first costal is about as long as the second and the third costals together. Its inner side bears the axillary buttress scar, where a rounded swelling links the scar to the first and second thoracic rib head. The fifth costal bears the inguinal buttress scar on its inner side, which extends nearly half the width of the plate along its center, as in most bothremydids. The posterior part of the sixth costal and the seventh and eighth costals meet on the midline, separating the neural series from the suprapygal. The suprapygal is triangular in shape, as in other bothremydids. The pygal is slightly longer than wide.</p> <p>The carapacial scales of Kurmademys do not differ significantly from those in Chedighaii and other bothremydids. The cervical scale is absent.</p> <p>PLASTRON</p> <p>The plastron in ISIR 278 consists of the posterior part of the left hyoplastron, left hypoplastron, left mesoplastron, and partial right hypoplastron. Other elements of this specimen are too badly broken to be recognizable. The plastron reconstruction is based mainly on ISIR 278, with information from ISIR 152S (right hyoplastron) and ISIR 157L (xiphiplastron). The entoplastron and both epiplastra are not known.</p> <p>The anterior lobe in Kurmademys is probably relatively long, as in Cearachelys, not short, as in the Bothremydini and Taphrosphyini, based on the lateral edges of the hyoplastra. The mesoplastron is equidimensional but larger than that bone in Chedighaii. The posterior lobe is wide, as in Chedighaii, with a semicircular-shaped anal notch.</p> <p>The plastral scales of Kurmademys are not well preserved. Only a lateral portion of the humeropectoral sulcus is present, and its position is very similar to that in Araiochelys, suggesting that the pectoral scale covers a small part of the epiplastron and a large part of the entoplastron. The pectoroabdominal sulcus is placed far anterior to the mesoplastron, also as in Araiochelys. The pelvic scars are similar to those in Chedighaii; the ischiac scar is triangular in shape and situated anterior to the posterior margin of the plastron.</p> <p>TRIBE CEARACHELYINI Cearachelys placidoi (fig. 258, table 22) MATERIAL AVAILABLE: THUg 1798 (Gaffney, Campos, and Hirayama, 2001: figs. 8, 9), a complete shell; BSP 1976 I 160, a complete shell; MPSC uncatalogued, type specimen (Gaffney, Campos, and Hirayama, 2001: figs. 6, 7), plastron and partial carapace.</p> <p>CARAPACE</p> <p>The carapace of Cearachelys is nearly complete in THUg 1798 and BSP 1976 I 160. Fragments of the left and right bridge peripherals are present in the MPSC specimen.</p> <p>The carapace of Cearachelys is moderately domed, much as in recent Pelomedusa. The carapace is composed of a nuchal, eight neurals, eight pairs of costals, 11 pairs of peripherals, a single suprapygal, and a single pygal. There are no fontanelles as in Araripemys, and all the bones are tightly sutured as in most pleurodires. The principal distinguishing features of the carapace in Cearachelys lie in the neural bones. The first neural in most Pelomedusoides is four-sided and contacts only the nuchal, first costals, and second neural. In Cearachelys the first neural is six-sided and has short, paired contacts with the second costals. In THUg 1798 the second neural is four-sided, rather than six-sided as in most Pelomedusoides, and as a consequence it does not contact the first costals. In Araripemys the second neural also does not contact the first costals.</p> <p>TABLE 22</p> <p>Possible Cearachelyini Shells</p> <p>However, in BSP 1976 I 160 the second neural also does not contact the first costals. However, in Munich BSP I 160 the second neural is asymmetric with five sides and a third costal contact only on the left side. The third neural in this shell is also asymmetric with five sides and a second costal contact only on the right side. Neurals 4–6 are the usual six-sided, coffin-shaped bones. Neurals 7 and 8 are smaller and more irregular, varying in the two carapaces. Neural 7 is six-sided, but the two lateral sides are nearly parallel rather than converging as in the other neurals. In both shells neurals 7 and 8 occupy the area between costals 7 and 8, but the neurals vary in size. In THUg 1798, neural 7 is much longer than neural 8 while in BSP 1976 I 160 they are nearly the same length. The triangular suprapygal contacts the last neural and is a bit wider in BSP 1976 I 160 than in THUg 1798.</p> <p>The eight costals of Cearachelys are similar to those in Chedighaii and Taphrosphys as well as Euraxemys. The 11 peripherals are also similar to the other bothremydids, being wider posteriorly. The carapacial scales of Cearachelys are quite similar to the generalized condition for Pelomedusoides seen in Chedighaii, Taphrosphys, and Podocnemis. Because of a complete neural series, the sulcus between vertebrals 4 and 5 falls on the seventh neural in THUg 1798 and nearly on the seventh-eighth neural suture in BSP 1976 I 160. As expected, the scales in Cearachelys differ from the unique condition in Araripemys in which the first vertebral enters the nuchal emargination and the first two marginals are widely separated.</p> <p>PLASTRON</p> <p>The plastron in Cearachelys is known in all three specimens. The plastron in BSP 1976 I 160 is complete, but the bone surface is damaged in some areas, precluding sulci preservation. THUg 1798 is nearly complete with all sutures and sulci preserved. The MPSC specimen is missing some of the anterior edges of the plastron, and the posterior margins of the xiphiplastra are broken off.</p> <p>The plastron of Cearachelys has a broad, semicircular anterior lobe and a tapering posterior lobe with a shallow xiphiplastral notch. The anterior lobe in Cearachelys is much broader than in Euraxemys and Araripemys. It agrees with Euraxemys and most pleurodires in being rounded and differs strongly from that in Araripemys, which is pointed. The epiplastra in Cearachelys meet on the midline for a length that is much more than in Araripemys but less than in Euraxemys. The entoplastron in Cearachelys is trapezoidal, not V-shaped as in Araripemys, and it does not have a curved posterior margin as in Euraxemys. The anterior lobe in Cearachelys is not as short as in the Taphrosphyini and Bothremydini, agreeing with Kurmademys.</p> <p>Paired, laterally placed mesoplastra are present in Cearachelys, as in Euraxemys and in contrast to Araripemys, which lacks them. The mesoplastra of Cearachelys are similar in size and shape to those in Podocnemis, Taphrosphys, and Chedighaii and are not very large as in Euraxemys. The axillary and inguinal buttress attachments are not visible in any of the specimens at their current stage of preparation. The xiphiplastron has a moderate posterior projection and a shallow xiphiplastral notch, much as in Chedighaii but in contrast to the pointed projections and C-shaped notch in Taphrosphys.</p> <p>The plastral scales in Cearachelys are much as in other Pelomedusoides. The intergular is roughly V-shaped and extends onto the entoplastron partially separating the humerals, as in Chedighaii and Podocnemis. The intergular extends onto the entoplastron slightly more than in Euraxemys but not as much as in Taphrosphys in which the intergular is large and completely separates the humerals. The humero-pectoral sulcus is behind the entoplastron, as in Euraxemys and Rosasia, but not crossing it, as in Foxemys, Polysternon, and Taphrosphys. The pectoral-abdominal sulcus crosses the anterior part of the mesoplastron, as in Chedighaii and most other Pelomedusoides. The other plastral scales are very similar to those in Chedighaii.</p> <p>TRIBE BOTHREMYDINI Foxemys mechinorum (fig. 259) MATERIAL AVAILABLE: MDEt 10, shell (figured in Tong et al., 1998: figs. 1, 2); PAM 548, shell (figured Tong et al., 1998: figs. 9, 10); MDEt 09, complete plastron; MDEt 11, right scapuloprecoracoid and several isolated plates (Tong et al., 1998); MDEt uncatalogued, nearly complete shell; MHNM uncatalogued specimen, a nearly complete shell.</p> <p>CARAPACE</p> <p>The shell morphology of Foxemys is very similar to that in Polysternon, although there are some differences (see Tong et al., 1998: table 1). The surface of the carapace and plastron in Foxemys is covered by the so-called ‘‘pelomedusoid’’ ornamentation, state 1 of character 175, that consists of fine forking and irregular vascular grooves, but the parallel striations seen in Polysternon are absent in Foxemys. The carapace outline is an elongated oval rather than more rounded, as in Polysternon and most other bothremydids, with a straight anterior margin and without a nuchal emargination. A wide posterior emargination on the carapace is present on the holotype (Tong et al., 1998), which is apparently an individual anomaly and is absent in other specimens.</p> <p>The nuchal is trapezoidal with a straight anterior margin. The anterior portions of the lateral margins of the nuchal are nearly parallel to each other in most specimens. The greatest width of the nuchal is usually about two times its anterior margin. There are seven neurals; their size and shape are similar to Polysternon, with the seventh and eighth pairs of costals meeting on the midline. The first neural is the largest and is roughly rectangular with slightly convex lateral margins. Its posterior end is usually slightly wider than the anterior end. The single, triangular suprapygal contacts the pygal and eleventh peripherals posteriorly. Eleven peripherals are present. The first one is roughly triangular with a short contact to the first costal.</p> <p>There is no cervical scale, as in all Pelomedusoides. The vertebral scales are all slightly wider than long. The first vertebral is restricted to the first peripheral in most specimens, but some shells, such as PAM 548 and the MHNM specimen, have the first vertebral extending onto the second peripheral plate. The second vertebral is as wide as the first in all Foxemys specimens, while the second vertebral is clearly narrower than the first one in the Polysternon from the Fuveau Basin. All marginal scales are restricted to the peripheral bones.</p> <p>PLASTRON</p> <p>The axillary buttress in Foxemys is large and inserts on the lateral part of the first costal plate. On the inner side of the first costal plate, a low, blunt, posteriorly convex ridge links the axillary scar to the first and second dorsal rib heads. The inguinal buttress contacts the eighth peripheral plate and the lateral third of the fifth costal.</p> <p>The plastron is slightly shorter than the carapace. The anterior lobe is short and wide at the base, as in other Bothremydini, with a nearly straight anterior margin. The bridge is longer than the posterior lobe, and the posterior lobe is longer than the anterior one. The lateral margins of the posterior lobe of Foxemys are less rounded than in Polysternon. The anal notch is large and wide, wider than in Polysternon.</p> <p>The length of the epiplastral symphysis is about one-third to one-half that of the entoplastron. The large and diamond-shaped entoplastron is wider than long in most specimens, but some of them, such as the MHNM specimen and MDEt 09, have the entoplastron as long as wide. The posterior end of the entoplastron reaches the level of the bridge, as in Polysternon, but differs from Rosasia, in which the entoplastron is more anteriorly placed. The hyoplastra and hypoplastra are about the same length. The mesoplastron is roughly semicircular in shape and longer than wide. The size of the mesoplastron varies compared to the entoplastron, from smaller (MDEt 10) to equal (MDEt 09, MNHM specimen, and PAM 548). On the inner side of the xiphiplastron, the pubic scar is an anteromedially orientat- ed, elongate oval, with an acute anterior tip. The ischiac scar is elongated and triangular in shape. Its anterior margin is transverse and its posterior tip is anterior to the anterior margin of the anal notch.</p> <p>The plastron has the usual 13 scales. The gular scales are large and triangular in shape, reaching but not crossing the anterior margin of the entoplastron. In PAM 548, MDEt 09, and most other specimens, the intergular is large, widely separating the gulars and extending for half the length of the entoplastron. In contrast, the shells in MDEt 10 and the MHNM specimen have a smaller intergular scale that reaches only the anterior third of the entoplastron. The humeral scale has a variable but short midline length, from 40 % to 8 % of the entoplastral length. The humeropectoral sulcus crosses the entoplastron posteriorly, about one-third to one-fourth of the length of the entoplastron, and then crosses the epihyoplastral suture about halfway along the length of the suture. The humeropectoral sulcus is entirely anteri- or to the epihyoplastral suture in MDEt 10. The pectoral scales cover the anterior two-thirds of the hyoplastra. The pectoroabdominal sulcus is straight and does not reach or barely reaches the mesoplastra. The abdominals are the largest plastral scales. They cover the posterior third of the hyoplastra and the anterior half of the hypoplastra and mesoplastra. The abdominofemoral sulcus is straight or slightly convex anteriorly, with the lateral ends curved posteriorly. The femoral scales cover the posterior half of the hypoplastra and the anterior part of the xiphiplastra. The femoroanal sulcus is convex anteriorly. The anal scales cover the posterior half of the xiphiplastra.</p> <p>Polysternon provinciale (fig. 260) MATERIAL AVAILABLE: Two shell fragments including an anterior portion of carapace (MHNM 1982-853), from ‘‘lignite de la grande Mène’’, Matheron collection (Matheron, 1869; Broin, 1977: fig. 1, pl. 1, fig. 3a,b; the other specimen was already lost when Broin [1977] reviewed the material); uncatalogued partial shell in the collection of the Musée Cantonal de Géologie de Lausanne (Portis, 1882); MHNM 1982-857, holotype of ‘‘ Elochelys major ’’ (Nopcsa, 1931: pl. XIII; Broin, 1977: fig. 2, pl. 1, fig. 1); MHNM 1982-855, internal cast showing the plastron with pubic and ischiac scars, collection Comte de Gérin-Ricard (Nopcsa, 1931: fig. 1; Broin, 1977: pl. 1, fig. 2, from ‘‘Valdonne’’); Costa collection, a complete shell (Buffetaut et al., 1996: fig. 4) and numerous plates.</p> <p>CARAPACE</p> <p>The shell surface ornamentation is figured by Portis (1882: pl. 28) and Broin (1977:</p> <p>pl. 1, fig. 3b). It consists of anteroposteriorly directed, thin parallel striations, along with the ‘‘pelomedusoid’’ texture pattern, consisting of fine forking and irregular vascular grooves (state 1, character 175). The parallel striations, state 3, are unique among bothremydids; they are well marked and cover the entire surface of the carapace on the Portis specimen. On the holotype and Villeveyrac specimens, they are well marked on the neurals and the medial part of the costals. They are weaker on the plastron than on the carapace and absent on the plastron. The ‘‘pelomedusoid’’ ornamentation is also visible on the peripherals and the plastron.</p> <p>The shell is low and a shortened oval in outline, different from that in Foxemys, which is an elongated oval. The nuchal emargination is present and shallow. The nuchal is trapezoidal and roughly as long as wide. There are seven neurals, with the first being the longest and having the laterally convex lateral margins as in Foxemys. The lengths of the neurals decrease from the front to the back. The second to sixth neurals are six-sided with short anterolateral sides. The seventh neural is five-sided and smaller. Eight costals are present; the first is the longest, but not as long as in Taphrosphys. The seventh and eighth pairs of costals meet on the midline. A single, triangular suprapygal contacts the pygal and the eleventh peripheral posteriorly, except in the Villeveyrac specimen, in which the suprapygal is narrower and does not contact the eleventh peripheral. There are 11 peripherals, all longer mediolaterally than anteroposteriorly in the Villeveyrac specimen, and the preserved posterior peripherals in Portis’ specimens (Portis, 1882: pl. 28). The first peripheral is roughly triangular with a short contact with the first costal, as in Foxemys but in contrast to Cearachelys, Chedighaii, and Rosasia in which the first peripheral is more rectangular with a longer contact with the first costal.</p> <p>The cervical scale is absent, as in all Pelomedusoides. The first vertebral is wider than the second one, in contrast to Foxemys, in which it is as wide as the second vertebral, and Cearachelys, Taphrosphys, Elochelys, and Rosasia, in which the first vertebral is narrower than the second one. The vertebrals 2–4 are longer than wide in the type shell, but wider than long in the Villeveyrac specimen.</p> <p>PLASTRON</p> <p>The plastron is shorter than the carapace. The anterior lobe is relatively short and wide at the base, as in other Bothremydini and Taphrosphyini. The bridge is longer than the posterior lobe; the latter is longer than the anterior lobe. The posterior lobe is wide with laterally convex lateral margins, differing from the nearly straight lateral margins of Araiochelys. The anal notch is deep and narrow. The pubic and ischiac scars are similar to those in Foxemys. The epiplastron is large with a rather long midline suture. The large entoplastron is diamond-shaped and slightly wider than long. The mesoplastron is laterally placed and smaller than the entoplastron.</p> <p>Thirteen scales cover the plastron. The intergular scale is roughly as wide as the gular scale and covers little of the entoplastron. The gular scale reaches the entoplastron but does not overlap it in the type. In the Villeveyrac locality, among seven epiplastra preserved, only one has the large gular scale reaching the entoplastron; on the others the gular scale is smaller and does not reach the entoplastron. The humeropectoral sulcus is located half to a third of the length along the entoplastron and close to the epihyoplastral suture, in contrast to Cearachelys, Galianemys, and Rosasia in which the humeropectoral sulcus is located far behind the epihyoplastral suture and posterior to the entoplastron. The pectoroabdominal sulcus barely reaches the mesoplastron or is located slightly anterior to it, in contrast to Araiochelys and Kurmademys in which this sulcus is located well anterior to the mesoplastron.</p> <p>Rosasia soutoi (fig. 261) MATERIAL AVAILABLE: Museu Minerologico e Geologico de la Faculdade de Ciencias, Universidade do Porto, uncatalogued type shell (figured in Carrington da Costa, 1940: pls. I, III); Universidade Nova de Lisboa, Portugal, MTA 1, shell (Antunes and Broin, 1988: pl. 3, figs. 1, 2), MTA 2, shell (Antunes and Broin, 1988: pl. 4, figs. 1, 2); two shells (only one figured) in the Serviços Geológicos de Portugal Lisbonne (Carrington da Costa, 1958: pls. 3, 4); one shell in the Faculdade de Ciencias e Tecnologia, Universidade de Coimbra (Carrington da Costa, 1958: pls. 5, 6).</p> <p>CARAPACE</p> <p>The present description is based on the descriptions and illustrations of Carrington da Costa (1940, 1958) and Antunes and Broin (1988). The shell surface of Rosasia is figured in detail by Carrington da Costa (1940: pl. II; 1958: pl. II). The texture is the ‘‘pelomedusoid’’ pattern, fine forking and irregular vascular grooves, as in many Pleurodira, especially bothremydids, but not as dense as in Taphrosphys (Antunes and Broin, 1988).</p> <p>The shell is low, with a rounded outline. The nuchal emargination is narrow and deep, mostly involving the nuchal. Antunes and Broin (1988) mentioned the absence of the nuchal emargination in the specimen of Coimbra; this may be due to damage of the anterior margin of the shell. The nuchal is wider than long, but the anterior margin is roughly equal to half of the maximum width. There are seven neurals: the first is four-sided, the following ones are six-sided with short anterolateral sides, and the last neural is five-sided. The seventh and eighth pairs of costals meet on the midline. The suprapygal is small and triangular in shape, with its length slightly larger than the width. The pygal is slightly longer than wide. The first costal is longer than the second and third costals together. The first peripheral is roughly rectangular in shape, with the anterior margin being only slightly longer than the posterior one, in contrast to Polysternon and Foxemys in which the first peripheral is more triangular.</p> <p>The cervical scale is absent, as in all Pelomedusoides. The second and third vertebral scales are roughly as long as wide. All marginal scales are restricted to the peripheral plates. The carapace has strong buttresses, as in podocnemidids and other bothremydids. The axillary buttress extends to the lateral half of the first costal plate and the inguinal buttress attaches to the fifth costal plate (Antunes and Broin, 1988). The pelvic girdle is sutured to the shell, as in all Pleurodira. Its contact with the carapace cannot be seen. The pubic scar is oval in shape, oblique, and relatively short and wide, not elongated, as in Taphrosphys. The ischiac scar is roughly triangular in shape and placed anterior to the anal notch.</p> <p>PLASTRON</p> <p>The anterior lobe of the plastron is short and wide at its base, as in most bothremydids, with a semicircular outline. The bridge is long, longer than the posterior lobe and longer than in other bothremydids. The posterior lobe is longer than the anterior one and has straight lateral margins convergent posteriorly. The anal notch is very shallow and wide. The entoplastron is small, diamond-shaped, and as long as wide. Its posterior end does not reach the level of the axillary notch. The mesoplastron is larger than the entoplastron and is slightly wider than it is long.</p> <p>The plastron is covered by 13 scales. The intergular scale overlaps about a third of the entoplastron. The gular scale is small and does not reach the entoplastron. The humeropectoral sulcus crosses the hyoplastron just posterior to the end of the entoplastron and is placed far behind the epihyoplastral suture, as in Cearachelys and Galianemys. The pectoroabdominal sulcus crosses the anterior part of the mesoplastron. The abdominofemoral sulcus is about midway along the hypoplastron, as in Cearachelys, Polysternon, and Foxemys, while in Araiochelys and Taphrosphys it is more anterior. The femoroanal sulcus is as in other bothremydids, crossing the xiphiplastron about midway.</p> <p>Araiochelys hirayamai (figs. 262, 263)</p> <p>MATERIAL AVAILABLE: THUg 3338, partially disarticulated shell (fig. 262), including left first and fifth costals, left third, seventh, and eighth peripherals and other fragments, nearly complete plastron and limb bones; MDEt 25, an incomplete and disarticulated shell, neurals 1–2, left costals 1–4 (the fourth is incomplete), right costals 2–5 (costals 3 and 5 are incomplete), left tenth and eleventh peripherals, one peripheral of bridge region, right hypoplastron and xiphiplastron, and other fragments. MDEt 25 is tentatively identified as Araiochelys hirayamai because of the similar size, the shape and the structure of the first and fifth costal plates, similar development of the axillary and inguinal buttress scars, the shape of the posterior lobe of the plastron, and the shape and position of the pubic and ischiac scars. Both MDEt 25 and THUg 3338 are from the Danian beds of the Ouled Abdoun Basin, Morocco. None of the plastron and only part of the carapace restoration are dependent on the identification of MDEt 25 as Araiochelys. CARAPACE</p> <p>The surface texture of the carapace and plastron is the usual network of fine furrows, the ‘‘pelomedusoid’’ texture (state 1, character 175). This pattern is less pronounced than that seen in Taphrosphys; the polygonal areas delimited by the furrows are flat rather than raised, as in Taphrosphys. The carapace is very thin in MDEt 25, measuring from 6 mm for neurals to less than 2 mm for the lateral end of the costal plates. In MDEt 25, only the first and the second neurals are preserved. The first neural is elongated and roughly rectangular in shape; it is slightly expanded at the midpoint and does not contact the second costal. The second neural is much shorter than the first and is pentagonal in shape with short anterolateral sides. It is in contact with the first neural anteriorly and the first costal anterolaterally. The following neurals are not preserved, but the complete medial margin of the second to fifth costal plates allows the reconstruction of the third to fifth neurals. The third to fifth neurals are all diamond-shaped and longer than wide, with their size decreasing from front to back. The posterior part of the second to fifth costals meets on the midline between the neurals. The sixth neural was present but not preserved, judging by the posteromedial margin of the fifth costal. It is probably smaller than the fifth neural.</p> <p>The complete left first costal is preserved in THUg 3338. In MDEt 25 the left first costal is nearly complete, but only a small fragment of the right one is preserved. The first costal is relatively long, with its length being greater than that of the second and third costals together, as in Taphrosphys sulcatus (Gaffney, 1975a). The inner surface of this plate bears a large scar for axillary buttress insertion that reaches halfway along the costal. A posteriorly convex, low ridge with an acute anterior edge links the axillary buttress scar to the first and second dorsal rib heads. This structure is present on both THUg 3338 and MDEt 25. The second to fourth costals are short, as in Taphrosphys and Chedighaii. The fifth costal is preserved in both THUg 3338 and MDEt 25, in which it widens distally; the inguinal buttress reaches its midpoint on the ventral side. The third peripheral is rectangular and longer than wide. The seventh, eighth, and tenth peripherals are roughly square in shape. The eleventh peripheral is wider than long. The posterior margin of the carapace is undulant.</p> <p>The scute sulci of the carapace are shallow but easily distinguishable. The first vertebral scale is not complete; only the posterior part of the left side is preserved. The first vertebral is clearly narrower than the second one. The second vertebral scale is very large and longer than wide. It is much larger than the third vertebral scale, with its posterolateral corner reaching the posterior margin of the third costal, which is a unique feature among bothremydids. The third vertebral scale is roughly square in shape. The intervertebral sulci cross the first neural medially, just anterior to the fourth neural and just posterior to the fifth neural.</p> <p>PLASTRON</p> <p>The plastron of THUg 3338 lacks the epiplastra and entoplastron; the anterior edge of both hyoplastra is damaged. In MDEt 25, the right hypoplastron and xiphiplastron are preserved. The hyoplastron is slightly widened at its anterior part. The mesoplastron is not completely known, but it seems to be slightly wider than long. The posterior lobe is narrow with nearly straight lateral margins. There is a shallow notch on the lateral border of the xiphiplastron at the lateral limit of the femoroanal scute sulcus in both THUg 3338 and MDEt 25. The anal notch is V-shaped, deep, and broad in THUg 3338. It has more curved borders in MDEt 25, which may be sexual dimorphism or may indicate a separate taxon. Both hypoplastron and xiphiplastron are much longer than wide. On the dorsal side of the xiphiplastron, the pubic scar is an elongated oval; it is less oblique and is placed closer to the lateral margin of the plastron than in Taphrosphys sulcatus (Gaffney, 1975a). The ischiac scar is roughly triangular in shape. It is posterior to the anterior margin of the anal notch, which differs from the condition in Foxemys, but it is not as close to the posterior margin of the plastron, as in Taphrosphys.</p> <p>The humeropectoral sulcus is preserved on the right hyoplastron of THUg 3338; it is posterior to the epihyoplastral suture, as in Taphrosphys and Chedighaii, but it probably crosses the entoplastron. The pectoroabdominal sulcus is preserved on the left hyoplastron; it is nearly straight and placed well anterior to the mesoplastron. The abdominofemoral sulcus is slightly convex anteriorly, crossing the midline at about one-third of the length of the hypoplastron. The femoroanal sulcus crosses the midline near the middle of the xiphiplastron.</p> <p>Chedighaii barberi (fig. 264, table 23)</p> <p>MATERIAL AVAILABLE: FMNH P 26055, shell (Schmidt, 1940: figs. 1–5); FMNH P2769, shell (Zangerl, 1948: fig. 3); FMNH P27372, shell (Zangerl, 1948: figs. 4, 7, 9,10); FMNH 27370, shell (Zangerl, 1948: figs. 5, 6, 11, 12, pl. 4, fig. 1); FMNH 27331, shell; FMNH P27405, shell; FMNH PR 247, shell (Gaffney and Zangerl, 1968: figs. 2, 3); ANSP 15902, shell (Gaffney and Zangerl, 1968: figs. 408); YPM 3608, shell (Gaffney and Zangerl, 1968: figs. 9–12); ALAB PV 2001.2, partial shell.</p> <p>CARAPACE</p> <p>Shell surface texture is the ‘‘pelomedusoid’’ pattern (Broin, 1977). The carapace is broadly rounded and low, as in Taphrosphys. The lateral margins converge posteriorly, with the widest point at the level of the seventh to eighth peripherals, then becoming narrower posteriorly.</p> <p>The posterior end of the carapace tapers to a blunt curve at the rear. It is wider than long (FMNH P27369, FMNH P27370, FMNH P27372, FMNH PR 247) or as long as wide (FMNH P26055). This is more like the shell of Taphrosphys (Gaffney, 1975a) but different from that of Galianemys and Cearachelys, in which the shell is an anteroposteriorly elongated oval. The nuchal emargination is present in all specimens with this part available, although its size and shape vary. In FMNH P26055, FMNH PR 247, and FMNH P27370, the nuchal emargination is narrow and deep, while FMNH P27369 and YPM 3608 have a shallower emargination.</p> <p>The carapace of Chedighaii barberi is composed of one nuchal, six or seven neurals, eight pairs of costals, 11 pairs of peripherals, one suprapygal, and one pygal, as in other Pelomedusoides. The nuchal is six-sided and short; it is clearly wider than long. Six neurals are present in FMNH P26055, FMNH P27370, FMNH P27372, FMNH P27331, and ANSP 15902, while FMNH PR 247, FMNH P27369, and YPM 3608 have seven neurals. The first neural is rectangular and only slightly longer than the second neural, except YPM 3608, which has a longer first neural. In most other bothremydids, the first neural is much longer than the second one (Cearachelys, Galianemys, Kurmademys, Foxemys, Polysternon). The second to fifth neurals are six-sided with short anterolateral sides. The sixth neural is as wide as long; it is five-sided when it is the last neural or six-sided when seven neurals are present. In both cases the sixth neural is as wide as the fifth one. The seventh neural, when present, is clearly smaller than the sixth. The first costal is longer than the second and third costals together, as in Taphrosphys. The sixth to eighth pairs of costals meet on the midline, separating the last neural from the suprapygal, when six neurals are present. In specimens with seven neurals, the seventh and eighth costals meet on the midline. The suprapygal is triangular, as in other Pelomedusoides. The first peripheral is four-sided, with the posterior margin being much shorter than the anterior one. The size of the peripherals increases from front to back, reaching the maximum size at the eighth and ninth peripherals. The tenth and eleventh peripherals are much smaller than the ninth one. The tenth and eleventh peripherals are also small in Taphrosphys, but the peripherals are generally narrower in it (Gaffney 1975a). The pygal is four-sided and nearly square, as in many Pelome-</p> <p>TABLE 23</p> <p>Comparison of Chedighaii barberi Shells dusoides, with the posterior margin being longer than the anterior one.</p> <p>The scale sulci on the carapace are preserved and figured in Schmidt (1940: fig. 2, FMNH P26055) and Zangerl (1948: pl. 4, fig. 1, AMNH P27370). They are partly visible in ANSP 15902 (Gaffney and Zangerl, 1968: fig. 4) and YPM 3608 (Gaffney and Zangerl, 1968: fig. 9). The general pattern of the scales of Chedighaii barberi agrees with that in other Pelomedusoides. The cervical scale is absent, as in all Pelomedusoides. The vertebral scales are all wider than long in FMNH P27370, FMNH P27372, and FMNH P27331, with strongly angled lateral margins. In FMNH P26055, ANSP 15902, and YPM 3608, the first to fourth vertebrals are narrower, with only slightly angled lateral margins. The first marginal is much wider than long,as in Galianemys but in contrast to Taphrosphys and Cearachelys in which it is square. All marginals are restricted to the peripherals, as in other bothremydids.</p> <p>On the inner side of the carapace, the axillary buttress scar lies on the lateral half of the first costal, near its posterior margin (Zangerl, 1948: fig. 7; Gaffney and Zangerl, 1968: figs. 5, 10). In Taphrosphys, the axillary scar is even more posteriorly placed (Gaffney, 1975a: fig. 4). The inguinal scar is less than half the width of the fifth costal, as in Taphrosphys. The iliac scar is placed on the posterior part of the seventh costal and eighth costals, overlapping slightly onto the suprapygal (Zangerl, 1948: fig. 9), as in Taphrosphys.</p> <p>PLASTRON</p> <p>The plastron in Chedighaii is shorter than the carapace, with the anterior margin posterior to that of the carapace, unlike Cearachelys and the possible Galianemys shells. The anterior lobe is short and wide, with a semicircular outline in FMNH P26055, ANSP 15902, FMNH PR 247, and FMNH P27370, in contrast to YPM 3608 and FMNH P27369, which have a more trapezoidal-shaped anterior lobe. The bridge is longer than the anterior lobe and shorter than the posterior lobe. The bridge is wide, as in Taphrosphys but in contrast to Galianemys, Foxemys, Polysternon, and Rosasia in which it is narrower. The posterior lobe is narrower than the anterior lobe, with the lateral margins tapering posteriorly, unlike Taphrosphys, which has the posterior lobe nearly as wide as the anterior one with nearly parallel lateral margins. The anal notch is deep and wide. It has an inverse V-shape in FMNH PR 247, FMNH P26055, and FMNH P27369 and a more U-shape in ANSP 15902.</p> <p>The plastron is composed of 11 plates, as in other podocnemidoids. The epiplastron is similar to Taphrosphys, with a comparatively short midline suture, except in YPM 3608 (Gaffney and Zangerl, 1968) and FMNH P26055. In Cearachelys the midline suture of the epiplastron is longer. The entoplastron is diamond-shaped and wider than long in most specimens (except ANSP 15902), as in Taphrosphys but differing from Galianemys in which it is as long as wide. The hyoplastron and hypoplastron are similar in length. The xiphiplastron is much longer than wide, as in most other bothremydids but in contrast to Taphrosphys in which this plate is equidimensional.</p> <p>On the inner side of the plastron, the pubic scar (Zangerl, 1948: fig. 11, pl. 4, fig. 2; Gaffney and Zangerl, 1968: figs. 8, 12) is oval and elongated, similar to that of Araiochelys. In Taphrosphys, the pubic scar is longer and narrower (Gaffney, 1975a: fig. 11). The ischiac scar of Chedighaii barberi is similar to that of Podocnemis. It is triangular, wider than long, and placed far anterior to the posterior margin of the plastron. In Taphrosphys, the ischiac scar is nearly rounded and is situated near the posterior margin of the plastron.</p> <p>The scale sulci on the plastron are only partly visible in FMNH P27369 (Zangerl, 1948: fig. 3), FMNH PR 247 (Gaffney and Zangerl, 1968: fig. 3), and YPM 3608 (Gaffney and Zangerl, 1968: fig. 11). There are some visible on ANSP 15902 (Gaffney and Zangerl, 1968: fig. 7) but only a few on the type specimen (although none figured, Schmidt, 1940: fig. 5). When all specimens from the Selma Formation at the Field Museum are taken together, all the scales are known for a composite reconstruction (fig. 264). The intergular scale is similar to that in Foxemys, extending about half the length of the entoplastron. The gular scale is triangular and wider than long, reaching the entoplastron but not crossing it. The humeropectoral sulcus is entirely posterior to the epihyoplastral suture, extending through the posterior third of the entoplastron. The pectoroabdominal sulcus is similar to that of Galianemys, crossing the mesoplastron. The abdominofemoral sulcus lies along the midpoint of the hypoplastron. The femoroanal sulcus is similar to that in Taphrosphys.</p> <p>TRIBE TAPHROSPHYINI Taphrosphys sulcatus (fig. 265, table 24) MATERIAL AVAILABLE: YPM PU 18706, partial shell collected by Regensburg and Dilkes, August, 1960, MFL Hornerstown Formation, Sewell, New Jersey (Gaffney, 1975a); YPM PU 18707, partial shell with associated limb and skull fragments, same data as in YPM PU 18706; YPM PU 18708, left xiphiplastron, same data as in YPM PU 18706; ANSP 15544, carapace with partial skull and limb elements, collected by Keith Madden and James Maddox from the MFL Hornerstown Formation, Inversand pits, Sewell, New Jersey (Richards and Gallagher, 1974; White, 1972); NJSM 10410, a plastron, no data; AMNH 1347, nuchal and first peripherals, ‘‘Cretaceous, New Jersey’’ (label), Cope Collection; AMNH 1470 (Hay, 1908: 119, fig. 119), neural bones, nuchal, and other shell fragments, ‘‘Barnsboro, 9/8 1870 ’’ (label), Cope Collection; AMNH 1472 (type of Taphrosphys molops Cope, figured in Cope, 1870: pl. 7, fig. 16; text-figs. 43, 44; Hay, 1908: figs. 112–116), nearly complete anterior lobe, incomplete xiphiplastron and other shell fragments, West Jersey Marl Company pits, Barnsboro, New Jersey, August 25, 1868, Cope Collection; AMNH 1474 (Hay, 1908: figs. 117, 118), partial plastron with incomplete right and left hypoplastra, complete left xiphiplastron and other fragments, Birmingham, New Jersey, Cope Collection; AMNH 1477 (Hay, 1908: fig. 120), shell fragments, West Jersey Marl Company pits, Barnsboro, New Jersey, 1855, Cope Collection; AMNH 1471 (Hay, 1908: fig. 106), anterior plastral bones, mixed with AMNH 1470 (label), Cope Collection; AMNH 1467 (type of Taphrosphys leslianus Cope, figured in Hay, 1908: figs. 103–105), partial shell, Hornerstown, New Jersey, collected by Dr. S. Lockwood, Cope Collection; AMNH 1125 (only the right first costal is labeled as 1124) (type of Taphrosphys longinuchus Cope, figured in Hay, 1908: figs. 101, 102), partial shell with limb fragments (this specimen was apparently mixed with the type of Adocus agilis Cope, AMNH 1135), David Haine’s marl pit, Medford, New (from Gaffney, 1975a). Dorsal view of carapace (left) and ventral view of plastron (right). [J. Kane, del.]</p> <p>Jersey, March 15, 1870, Cope Collection; AMNH 1468 (Cope, 1870: 166, fig. 45; not that two consecutive figures in Cope [1870] are both labeled fig. 45 but illustrate different specimens; Hay, 1908: figs. 99, 100), shell fragments, Barnsboro, New Jersey, Cope Collection; AMNH 1469, shell fragments, West Jersey Marl Company pits, Barnsboro, New Jersey, 1869, Cope Collection; AMNH 2524 (Cope, 1870: 165, fig. 45), nuchal bone, Barnsboro, New Jersey, in the Rutgers University Cook Collection until 1970; AMNH 1126, plastron fragments, incomplete ilium and humerus, and other shell fragments, type of Taphrosphys strenuous, ‘‘?Hornerstown Formation (Upper Greensand), Barnesboro, Gloucester Col, New Jersey, Cope Collection’’ (label); AMNH 1128, shell fragments, including one neural and several fragments of costals, ‘‘ Taphrosphys molops, Cope Collection’’ (label); AMNH 14754, incomplete nuchal and first peripherals, one neural, incomplete xiphiplastron, and other shell fragments; Taphrosphys sulcatus, shell fragments, MFL Hornerstown Formation, HT-1, Hornerstown type locality, Hornerstown, Monmouth Co., New Jersey, coll. E. S. Gaffney.</p> <p>CARAPACE</p> <p>The best previously published reconstructions of Taphrosphys sulcatus are those based on AMNH 1125 by Hay (1908: figs. 101, 102) and YPM PU 18706 by Gaffney (1975a). The two best preserved shells, YPM PU 18706 and YPM PU 18707, were described in Gaffney (1975a). Most of the material of Taphrosphys, particularly in the AMNH, YPM, NJSM, and ANSP collections, is fragmentary. Taphrosphys sulcatus has prominent surface texture on both carapace and plastron, consisting of irregular raised polygons separated by a network of deep furrows. This kind of sculpture (state 2, character 175) is different from the more common ‘‘pelomedusoid’’ texture (state 1) defined by Broin (1977) and found in other bothremydids. The carapace of Taphrosphys is a short oval, with a narrow anterior end and the lateral margins diverging posteriorly, reaching their widest point at the level of the seventh peripherals and then narrowing to a blunt posterior end.</p> <p>TABLE 24</p> <p>Comparison of Taphrosphyini Shells</p> <p>This shape is very similar to Chedighaii, unlike the oval carapace in Galianemys, Cearachelys, Kurmademys, and Foxemys.</p> <p>The nuchal is trapezoidal and as long as wide in AMNH 1125 and YPM PU 18706, but wider than long in ANSP 15544 (Gaffney, 1975a). Another complete nuchal is preserved in AMNH 1347 and an incomplete nuchal is preserved in AMNH 1467 and AMNH 14754. The nuchal emargination is absent in all these specimens with the nuchal preserved; the front margin of the nuchal is straight or slightly convex anteriorly. The neural series consists of seven continuous neurals, based on ANSP 15544, YPM PU 18706, and YPM PU 18707 (Gaffney, 1975a), as in Foxemys, Polysternon, and Rosasia. The first neural is clearly longer than the second one. It is four-sided with the convex lateral margins, as in Foxemys and Polysternon. The second to fifth neurals are six-sided with short anterolateral sides and are longer than wide. The sixth neural is nearly equidimensional. The seventh neural is five-sided and much smaller than the sixth neural. AMNH 1463 has the last neural preserved and the seventh and eighth costals meeting on the midline. The first costal is longer than twice the length of the second costal, as in Chedighaii and Araiochelys. The seventh and eighth costals meet on the midline, separating the neurals from the suprapygal. The suprapygal is triangular and nearly as long as wide. The pygal, preserved in YPM PU 18707, is wider than long with a convex posterior margin.</p> <p>On the visceral surface of the shell, the axillary buttress scar is on the lateral half of the first costal, near the posterior margin of the plate. The first rib head is smaller than the second one. The inguinal buttress reaches about half the width of the fifth costal. The iliac scar covers the posterior part of the seventh and eighth costals and slightly overlaps onto the suprapygal in AMNH 1468, YPM PU 18706, and YPM PU 18707, but in AMNH 1125, the iliac scar reaches the anterolateral margin of the suprapygal but does not overlap onto it.</p> <p>The cervical scale is absent, as in all Pelomedusoides. As in the reconstruction in Hay (1908: fig. 101) and Gaffney (1975a: fig. 1), the first vertebral is narrow; it is narrower than the second and third vertebrals, especially in YPM PU 18706. The second and third vertebrals are wider than long and the fourth vertebral is narrower. The marginal scales are restricted to the peripheral bones, as in all Pelomedusoides.</p> <p>PLASTRON</p> <p>The plastron of Taphrosphys sulcatus is composed of 11 plates, as in other bothremydids. The plastron is shorter than the carapace; its front margin does not reach the anterior margin of the carapace, as in Chedighaii, Polysternon, and Foxemys but in contrast to Galianemys and Cearachelys.</p> <p>The plastron of Taphrosphys sulcatus has a very short and semicircular anterior lobe, as in Chedighaii. The bridge is longer than the anterior lobe and shorter than the posterior one, also as in Chedighaii. The bridge is relatively wide, as in Chedighaii and Araiochelys, not as narrow as in most other bothremydids. The posterior lobe is relatively wide, nearly as wide as the anterior lobe, with nearly parallel lateral margins, in contrast to Chedighaii in which the posterior lobe tapers posteriorly. The anal notch is rounded and very broad.</p> <p>The epiplastron has a short midline suture, much shorter than the entoplastral length. The entoplastron is complete in AMNH 1472 and YPM PU 18706. It is diamond-shaped and clearly wider than long. The mesoplastron is not preserved in any of the specimens. The xiphiplastron is broad, being nearly as wide as long (YPM PU 18708, AMNH 1125), or slightly longer than wide (AMNH 1474 and YPM PU 18706), in contrast to Bothremydini in which it is much longer than wide.</p> <p>The plastron in Taphrosphys sulcatus is covered by 13 scales, as in all Pelomedusoides. The intergular, preserved in YPM PU 18706 (Gaffney, 1975a: fig. 2) and AMNH 1472 (Hay, 1908: fig. 116), is very large, completely separating the gulars and humerals, as in Taphrosphys congolensis and Ummulisani but in contrast to all other bothremydids (except Elochelys). The gular scale, preserved in YPM PU 18706 (Gaffney, 1975a: fig. 2) and AMNH 1471 (Hay, 1908: fig. 106), is triangular; it reaches the entoplastron but does not cross it. The humeropectoral sulcus is behind the epihyoplastral suture, crossing the entoplastron, as in Chedighaii. As in Taphrosphys congolensis and Ummulisani, T. sulcatus has a very short abdominal scale, with the pectoroabdominal sulcus lying near the hyohypoplastral suture, in contrast to all other bothremydids (except ‘‘ T.’’ olssoni and ‘‘ T.’’ ambiguous, fig. 267).</p> <p>On the inner side of the plastron, the pubic scar is long and narrow. The ischiac scar is very small and rounded, placed very near the margin of the anal notch (Gaffney, 1975a).</p> <p>Taphrosphys congolensis (fig. 266, table 24)</p> <p>MATERIAL AVAILABLE: This description is based primarily on the description and illustrations of Dollo (1913) and Wood (1975), although one of us (E.S.G.) has seen the material.</p> <p>CARAPACE</p> <p>The shell surface of T. congolensis is covered by ‘‘a network of deeply inscribed anastomosing vermiculations’’, as described by Wood (1975: 139), as in Taphrosphys sulcatus. The carapace is known only from the anterior portion and the posterior third. The preserved part is very similar to T. sulcatus. On the lectotype of T. congolensis (Dollo, 1913: pl. VII, figs. 1, 2; Wood, 1975: fig. 1), the nuchal and the first peripheral are represented only by fragments and their shapes are therefore undeterminable. The second peripheral is roughly square and the third one is longer than wide, as in T. sulcatus (YPM PU 18706 and YPM PU 18707, Gaffney, 1975a: figs. 1, 6, 8). The first costal is as long as in T. sulcatus. On the inner side, the axillary buttress attaches to the third peripheral and the lateral half of the first costal, although its position appears to be more anterior than in T. sulcatus (Gaffney, 1975a: fig. 4). A posterior portion of carapace (MRAC 4795) consists of the last neural, right fifth to eighth costals, left seventh and eighth costals, suprapygal, pygal, and right eighth to eleventh peripherals (Wood, 1975: pls. 1, 2). The preserved neural, between the sixth and seventh costals, is the seventh neural. It is therefore likely that seven neurals are present in T. congolensis, as in T. sulcatus. The last neural is small and short, as in T. sulcatus.</p> <p>On the inner surface of the carapace, the inguinal buttress attaches to the eighth peripheral and the fifth costal. The iliac scar is on the seventh and eighth costals and covers a small part of the suprapygal, all similar to T. sulcatus.</p> <p>PLASTRON</p> <p>A nearly complete plastron (MRAC 4794) and two more-or-less complete xiphiplastra are figured in Wood (1975: pls. 3, 4, 6). The general morphology of the plastron of T. congolensis is similar to that of T. sulcatus. However, the plastron of T. congolensis seems wider than that of T. sulcatus. The reconstruction by Wood (1975: fig. 2) shows a narrow bridge relative to that of T. sulcatus. The posterior lobe has the lateral margins slightly tapering posteriorly, instead of nearly parallel as in T. sulcatus. The xiphiplastron is slightly longer than wide in MRAC 4794, while the complete xiphiplastron in plate 6 (Wood, 1975) is broader. Another diagnostic feature of T. congolensis pointed out by Wood (1975) is that its intergular is hexagonal and wider than in T. sulcatus. It is nearly as broad as long; while in other Taphrosphys species, the intergular is much longer than wide. The comparison of species referred by various authors to Taphrosphys is shown in table 24.</p> <p>Ummulisani rutgersensis (figs. 268, 269)</p> <p>MATERIAL AVAILABLE: AMNH 30562, a nearly complete plastron associated with skull and jaws.</p> <p>PLASTRON</p> <p>The plastron of Ummulisani has the usual 11 bones and 13 scales and is very similar to the plastron of Taphrosphys. The epiplastra are slightly larger relatively in Ummulisani than in Taphrosphys, and the anterior plastral lobe is relatively wider. The entoplastron in Ummulisani is wider than long, as in Taphrosphys. The hyo- and hypoplastra are very similar in both genera. The mesoplastron in Ummulisani lacks the lateral edges, but it seems to be larger than the mesoplastron in Chedighaii. The xiphiplastron in Ummulisani has the narrow posterior projection and broad, semicircular anal notch of Taphrosphys, but it is slightly narrower posteriorly.</p> <p>On the visceral surface, the buttresses are mostly broken away. The pubic scar is long and narrow in Ummulisani, as in Taphrosphys. The ischiac scar is round as in Taphrosphys, but it is not right on the edge of the xiphiplastron as in Taphrosphys.</p> <p>The plastral scales of Ummulisani are similar to those in Taphrosphys. There is a large intergular that occupies most of the entoplastron, widely separating the gular and humeral scales. In contrast to Taphrosphys, the gular scales extend onto the entoplastron a short distance in Ummulisani. The abdominal scales are narrow and the femorals are large, as in Taphrosphys.</p> <p>PELOMEDUSOIDES INDETERMINATE</p> <p>? Galianemys sp. (table 22, figs. 271–274)</p> <p>MATERIAL AVAILABLE: AMNH 30550, nearly complete shell (figs. 273, 274), Cenomanian, Kem Kem, Morocco; AMNH 30551, nearly complete shell (figs. 271, 272), Cenomanian, Kem Kem, Morocco. There are differences between these two shells (table 22), and it is possible they represent two taxa (see below). The named turtles known from skulls occurring in the Kem Kem Campanian of Morocco are Galianemys emringeri, Galianemys whitei, Hamadachelys, and Dirqadim, but a phylogenetic analysis including these shells (fig. 294) places them in the tribe Cearachelyini, suggesting that they may be the shells for one or both Galianemys species.</p> <p>CARAPACE</p> <p>The two shells have an oval outline, slightly expanded posteriorly. There is no nuchal emargination. AMNH 30551 has eight neurals with costal 8 meeting on the midline. AMNH 30550 has six neurals with costals 7 and 8 meeting on the midline (see table 22). In AMNH 30551 the nuchal is</p> <p>(right). [E.S. Gaffney, del.]</p> <p>slightly wider than it is long, with a long anterior margin. The first neural is six-sided with short posterolateral sides contacting the second costal as in Cearachelys and different from all other bothremydids. The second neural is four-sided and short, as in Cearachelys. The third to fifth neurals are six-sided with short anterolateral sides and are longer than wide. The sixth and seventh neurals are wider than long and the eighth neural is reduced and pentagonal in shape; it does not contact the suprapygal. The first costal is similar to that of Cearachelys, being shorter than the length of the second and third costals together. The eighth pair of costals meets on the midline in AMNH 30551 and the seventh and eighth pairs of costals meet on the midline in AMNH 30550 between the neural series and the suprapygal, in contrast to Cearachelys in which the costals are completely separated by the neural series. The suprapygal is roughly triangular in shape, as in other Pelomedusoides; it is wider than long.</p> <p>The carapace scales are similar to the generalized scale pattern of other Pelomedusoides. The cervical is absent. The second and third vertebrals are roughly as long as wide, different from Cearachelys in which these two scales are wider than long. The marginals are restricted to the peripherals as in all Pelomedusoides.</p> <p>PLASTRON</p> <p>The plastron is sutured to the carapace. The plastron is long; its anterior margin reaches the anterior margin of the carapace, as in Cearachelys. The anterior lobe is short and wide at the base, with a semicircular outline, as in most bothremydids but different from Cearachelys, which is longer. The mesoplastron is laterally placed and longer than wide. The bridge is long, longer than the posterior lobe, in contrast to Cearachelys, in which the bridge is shorter than the posterior lobe. The anal notch is V-shaped.</p> <p>The plastron scale pattern differs between the two shells. The intergular scale is narrow</p> <p>(right). [J. Kane, del.]</p> <p>in AMNH 30551 and it covers about a third of the entoplastron. The gular scale is larger, extending onto the entoplastron, and is much wider than the intergular, a uniquecondition among bothremydids. In AMNH 30550, the intergular is wide, larger than the gular scales, which do not extend onto the entoplastron. In both, the humeropectoral sulcus is entirely posterior to the epihyoplastral suture and just behind the entoplastron, as in Cearachelys. The pectoroabdominal sulcus crosses the mesoplastron in both shells, as in Cearachelys and Euraxemys.</p> <p>Three genera of turtles have been collected in the Cenomanian Kem Kem beds: Galianemys (Bothremydidae), Hamadachelys (Podocnemididae), and Dirqadim (Euraxemydidae), all based on isolated skulls. This turtle fauna has a strong affinity with the Early Cretaceous turtle fauna of the Santana Formation. The shells from Kem Kem described above are similar to bothremydids in the shape of the anterior lobe of the plastron. The shells from Kem Kem share with Cearachelys the first neural being six-sided with short posterolateral sides contacting the second costal and the four-sided second neural. This character is not known in any other Pelomedusoides. This suggests that the shells may belong to Galianemys. The phylogenetic analysis supports this hypothesis by placing these shells in the tribe Cearachelyini. The comparisons between the shells of Galianemys and Cearachelys are shown in table 22.</p> <p>There is evidence that the? Galianemys shells are not the same taxon. AMNH 30551 has eight neurals with costal 8 meeting on the midline, and a very narrow intergular scale flanked by large gulars that extend onto the entoplastron. This is in contrast to AMNH 30550 that has six neurals with costals 7 and 8 meeting on the midline, and a wide intergular flanked by smaller gulars that do not extend onto the entoplastron. A fine kettle of fish.</p> <p>+ Fig. 275. Bairdemys venezuelensis (Wood and Díaz de Gamero, 1971). MCZ 9420. Miocene, Venezuela. Ventral view of shell. This species is in the Podocnemididae based on skull characters (Gaffney and Wood, 2002), but the plastron has strong similarities to many bothremydid plastra (see text). [J. Kane, del.]</p> <p>(right). [J. Kane, del.]</p> <p>PHYLOGENETIC ANALYSIS</p> <p>METHODOLOGY</p> <p>The phylogenetic analyses were made with PAUP* version 4.0b10 (Swofford, 2002) using the parsimony algorithm. All characters were run unweighted and unordered, although there is a good argument for ordering at least two characters (characters 20 and 94, see Character Descriptions for discussion). Characters were entered and cladograms examined using MacClade version 4.05 (Maddison and Maddison, 2000). The data matrix (appendix 3) used as the basis of this analysis has 41 taxa and 175 characters (of these, only 171 are parsimony informative for the core analysis, cladogram 1 [fig. 288], due to the presence of some shell characters that vary only in taxa absent in the core analysis; see below). The PAUP analysis of this matrix, using both heuristic and stepwise addition (random), results in one shortest cladogram (fig. 288) of 382 steps with a consistency index of 0.60, a retention index of 0.81, a rescaled consistency index of 0.49, and a homoplasy index of 0.39. Bootstrapping was run using 100 replicates. Bremer decay indices were obtained using TreeRot version 2 (Sorenson, 1999).</p> <p>One caution in using the dataset provided in appendix 3 is the amount of missing data. Taxa with large numbers of missing characters are a concern because the analytic program supplies the missing characters as most consistent with the shortest cladogram, thus ignoring the likely interference of contradictory characters commonly present. Even so, inclusion of taxa with missing data can produce useful results (Kearney and Clark, 2003). Table 25 lists the amount of missing data for each taxon.</p> <p>As shown in the decay analysis, there are some groups that lose resolution in the consensus of the 38 cladograms that are one step longer than the MPC. This consensus tree (fig. 289) shows that the Bothremydini loses resolution, with the Foxemydina becoming a multichotomy with the Taphrosphyini and remaining Bothremydini. Zolhafah and Rosasia form a multichotomy with the remaining Bothremydini. The genus Bothremys is paraphyletic with respect to Chedighaii. All the other tribes hold up, but the two species of Galianemys form a multichotomy with Cearachelys. Within the Taphrosphyini, there is a loss of resolution in the basal members, and the species in the genus Taphrosphys are paraphyletic with respect to a Phosphatochelys + Ummulisani + Rhothonemys trichotomy. Araripemys and the Pelomedusidae form a trichotomy with the remaining Pelomedusoides. All of these alternatives are quite reasonable, as they are held together by few characters. Two particular characters that seem a little more subjective than the others, at least in part, are characters 31 and 110 (see Character Descriptions for discussion). Deleting these characters produces 38 trees with the consensus cladogram seen in figure 290.</p> <p>The 40 taxa in the core analysis are all represented by good skull material; of these, 21 also have associated shells (fig. 291A) and 20 have associated lower jaws (fig. 291B). The shells are relatively well distributed taxonomically with at least one skull-shell association in each tribe of Bothremydidae (see also fig. 314, character 164). In the dataset skull characters are 70 % (122) of the 175 characters, shell characters are 21 % (38), and the remaining 9 % (14) are other postcranial characters. When all postcranial characters are deleted, the same single cladogram (fig. 288) results, showing the dominance of cranial characters in the dataset and their critical importance to the analysis. The addition of a selected group of eight shell-only taxa to the dataset (indicated by asterisk in fig. 292 and in appendix 3) also results in one cladogram, cladogram 2 (fig. 292). However, these shell-only taxa are not representative of the majority of named shell-only taxa. They have been chosen because they have few missing data and do not generate large numbers of trees. Some shell-only taxa (see section on Dubious Taxa) are represent- ed by very incomplete specimens and have been excluded from this analysis and the resulting cladograms.</p> <p>The influence of shells on the analysis can be observed by examing the results following the exclusion of all cranial characters. The basic dataset (appendix 3) was modified by</p> <p>TABLE 25 Missing Data Taxa with asterisks are shell-only specimens added to the analysis in figure 292. Taxa with two asterisks have high missing data values, are treated in figures 294 and 295, and are discussed in text.</p> <p>TABLE 25</p> <p>Continued</p> <p>dropping all cranial characters and all skull-only taxa, with the result seen in figure 293A. This restricted dataset has 28 taxa and 39 characters and produced 2704 trees in a PAUP parsimony analysis with no ordering or weighting. The Pleurodira, Megapleurodira, and Eupleurodira are resolved along with a few lower level bothremydid groups, but most Pelomedusoides form a multichotomy. Admittedly, only 39 characters for 28 taxa are too few to expect complete resolution, but we have used as many shell characters as possible in the analysis. The poor showing of shell characters here seems to be the result of the general conservatism of Pelomedusoides shells. It is possible to find shell characters for alpha-level diagnoses and differentiation in this group. However, even these characters may be questioned because individual variation is so poorly known, and more inclusive comparisons are difficult given our current knowledge of skull-shell associations. Furthermore, most descriptive work on shells emphasize the external suture and scale relations, while many characters can be found in the more complex internal morphology.</p> <p>In any case, for whatever reason, with the present state of knowledge of this group, the shell alone provides little help in resolving relationships among Pelomedusoides. However, when included with the cranial characters, shell characters do help resolve some groups (see Character Descriptions). In an effort to try squeezing something more out of the shell-only dataset, it has been reanalyzed by weighting using the rescaled consistency index option in PAUP, which is a way of reducing the weight of the more homoplastic characters in favor of the more consistent characters. The resulting consensus of 250 equally parsimonious trees (fig. 293B) is interesting in that it unites almost all bothremydids (shown by asterisks) and excludes the Podocnemididae from the bothremydids.</p> <p>In order to try to incorporate as much information as possible from the more poorly known shell-only taxa, some have been added singly to the dataset. Most of these are discussed in the Incertae Sedis section following Systematics. Nearly all of these taxa are shells or partial shells, with some lacking as much as 95 % of the characters (for effects of missing data and possible solutions, see Wilkinson, 1995, 2003; Strauss et al., 2003; and Wiens, 2003). Some of these may represent shells of named skulls used in the basic list (e.g., Galianemys and AMNH 30550, AMNH 30551). Adding these taxa to the basic list one at a time allows some resolution of their phylogenetic position and a determination of a level of incertae sedis within a higher taxon without large numbers of trees obscuring the result.</p> <p>BASIC TAXA OUTSIDE PELOMEDUSOIDES</p> <p>Although the Pelomedusoides is the focus of this paper, outgroups are significant in the phylogenetic analysis, and there are taxa that have been identified as pleurodires in the literature that are of questionable status and require discussion.</p> <p>Synapsida/ Diapsida</p> <p>In order to root the turtle taxa, the main groups of amniotes outside turtles are included as a single taxon. We consider turtles to be the sister group of diapsids, not within diapsids or within pareiasaurs/procolophonids. There are polymorphic codings for some characters, and certain characters that are turtle synapomorphies, like plastral features, are coded ‘‘?’’, so this should not be considered a useful exercise in determining turtle relationships within amniotes. For further literature on these taxa and for other analyses of amniote relationships, see Lee (1997) and Rieppel and Reisz (1999). We are not dealing with the relationships of extinct groups like pareiasaurs and procolophonids to turtles, because to do so would not alter relationships within turtles. We do not consider the hypothesis that turtles are within diapsids (e.g., Braga and Rieppel, 1997) to have merit, but even accepting this would not alter relationships within turtles as analyzed here. Proganochelys still comes out as the sister group to cryptodires plus pleurodires.</p> </div>	https://treatment.plazi.org/id/4E7B8791CEA7FD83FF58FB0B11F1896A	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	GAFFNEY, EUGENE S;TONG, HAIYAN;MEYLAN, PETER A	GAFFNEY, EUGENE S, TONG, HAIYAN, MEYLAN, PETER A (2006): EVOLUTION OF THE SIDE-NECKED TURTLES: THE FAMILIES BOTHREMYDIDAE, EURAXEMYDIDAE, AND ARARIPEMYDIDAE. Bulletin of the American Museum of Natural History 300 (300): 1-698, DOI: 10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2, URL: http://dx.doi.org/10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2
4E7B8791CD56FD83FD59FC2C16EA8C07.text	4E7B8791CD56FD83FD59FC2C16EA8C07.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Australochelys Gaffney & Kitching 1994	<div><p>Australochelys</p> <p>Gaffney and Kitching (1994 and 1995) described this form.</p></div> 	https://treatment.plazi.org/id/4E7B8791CD56FD83FD59FC2C16EA8C07	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	GAFFNEY, EUGENE S;TONG, HAIYAN;MEYLAN, PETER A	GAFFNEY, EUGENE S, TONG, HAIYAN, MEYLAN, PETER A (2006): EVOLUTION OF THE SIDE-NECKED TURTLES: THE FAMILIES BOTHREMYDIDAE, EURAXEMYDIDAE, AND ARARIPEMYDIDAE. Bulletin of the American Museum of Natural History 300 (300): 1-698, DOI: 10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2, URL: http://dx.doi.org/10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2
4E7B8791CD56FD83FD59F9FC11128ECA.text	4E7B8791CD56FD83FD59F9FC11128ECA.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Kayentachelys	<div><p>Kayentachelys</p> <p>This taxon is described in Gaffney et al. (1987), with some additions in Gaffney (1990) and Gaffney and Kitching (1995).</p></div> 	https://treatment.plazi.org/id/4E7B8791CD56FD83FD59F9FC11128ECA	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	GAFFNEY, EUGENE S;TONG, HAIYAN;MEYLAN, PETER A	GAFFNEY, EUGENE S, TONG, HAIYAN, MEYLAN, PETER A (2006): EVOLUTION OF THE SIDE-NECKED TURTLES: THE FAMILIES BOTHREMYDIDAE, EURAXEMYDIDAE, AND ARARIPEMYDIDAE. Bulletin of the American Museum of Natural History 300 (300): 1-698, DOI: 10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2, URL: http://dx.doi.org/10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2
4E7B8791CD56FD83FD59FBBA11218E42.text	4E7B8791CD56FD83FD59FBBA11218E42.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Palaeochersis	<div><p>Palaeochersis</p> <p>This form is described in Rougier et al. (1995). However, the senior author has studied this material and some undescribed specimens (kindly made available by Andrea Arcucci) and has made corrections to the character matrix used by them (Rougier et al., 1995). In particular, the possible suturing of the pelvis described by Rougier et al. (1995) is incorrect. In the opinion of the senior author, the pelvis of Palaeochersis is not sutured to the shell; rather, the appearance of this is due to dorsoventral crushing and deformation. The pelvis articulation in Palaeochersis is the same as in Proganochelys. The basicranium in Palaeochersis is fused, not an open articulation as in Proganochelys, and the cavum tympani is advanced over Proganochelys, all as described by Rougier et al. (1995).</p> </div>	https://treatment.plazi.org/id/4E7B8791CD56FD83FD59FBBA11218E42	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	GAFFNEY, EUGENE S;TONG, HAIYAN;MEYLAN, PETER A	GAFFNEY, EUGENE S, TONG, HAIYAN, MEYLAN, PETER A (2006): EVOLUTION OF THE SIDE-NECKED TURTLES: THE FAMILIES BOTHREMYDIDAE, EURAXEMYDIDAE, AND ARARIPEMYDIDAE. Bulletin of the American Museum of Natural History 300 (300): 1-698, DOI: 10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2, URL: http://dx.doi.org/10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2
4E7B8791CD56FD83FD59FE04115C8BBD.text	4E7B8791CD56FD83FD59FE04115C8BBD.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Proganochelys (Gaffney 1990)	<div><p>Proganochelys</p> <p>The principal work on this taxon is Gaffney (1990). There is abundant support that Proganochelys is the sister taxon to all other turtles.</p> <p>Kordikova (2002) has published new line drawings of the skull of Proganochelys showing sutures different from those in Gaffney (1990). In the opinion of the senior author, Kordikova has inadvertently mistaken cracks for sutures. Lucas et al. (2000) have identified a partial dermal ossicle from the Upper Triassic of New Mexico as a probable turtle, very close to Proganochelys. Although it is not clear what this fragment belongs to, the senior author thinks its identification as a turtle lacks credibility, and this potential range extension should be ignored.</p> </div>	https://treatment.plazi.org/id/4E7B8791CD56FD83FD59FE04115C8BBD	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	GAFFNEY, EUGENE S;TONG, HAIYAN;MEYLAN, PETER A	GAFFNEY, EUGENE S, TONG, HAIYAN, MEYLAN, PETER A (2006): EVOLUTION OF THE SIDE-NECKED TURTLES: THE FAMILIES BOTHREMYDIDAE, EURAXEMYDIDAE, AND ARARIPEMYDIDAE. Bulletin of the American Museum of Natural History 300 (300): 1-698, DOI: 10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2, URL: http://dx.doi.org/10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2
4E7B8791CD55FD80FF42FA15116989C1.text	4E7B8791CD55FD80FF42FA15116989C1.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Notoemys Cattoi and Freiburg 1961	<div><p>Notoemys</p> <p>Notoemys laticentralis has been described by Cattoi and Freiburg (1961), Fuente and Fernandez (1989), and Fernandez and Fuente (1994). Rueda and Gaffney (2005) have described another species, N. zapatocaensis, and have argued that ‘‘ Caribemys ’’ oxfordiensis belongs in Notoemys, a conclusion we accept. Notoemys laticentralis is known from the shell, some vertebrae, some appendicular elements, and a partial skull. Although we have been unable to examine the partial skull, we suspect that the bone anterolateral to the basisphenoid in Fernandez and Fuente (1994: fig. 2B) is the pterygoid rather than the quadrate, as in chelids and pelomedusids. Although a partial skull is known for Notoemys, we have been able to code only a few characters for it, and, at least for the present, recognize Notoemys as another shell-only taxon.</p> </div>	https://treatment.plazi.org/id/4E7B8791CD55FD80FF42FA15116989C1	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	GAFFNEY, EUGENE S;TONG, HAIYAN;MEYLAN, PETER A	GAFFNEY, EUGENE S, TONG, HAIYAN, MEYLAN, PETER A (2006): EVOLUTION OF THE SIDE-NECKED TURTLES: THE FAMILIES BOTHREMYDIDAE, EURAXEMYDIDAE, AND ARARIPEMYDIDAE. Bulletin of the American Museum of Natural History 300 (300): 1-698, DOI: 10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2, URL: http://dx.doi.org/10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2
4E7B8791CD55FD80FF42FB5117E58D78.text	4E7B8791CD55FD80FF42FB5117E58D78.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Platychelys Wagner 1853	<div><p>Platychelys</p> <p>Platychelys has been described by Lang and Rütimeyer (1866), Rütimeyer (1873), Zittel (1877), Bräm (1965), and Lapparent de Broin (2001). As another shell-only taxon, Platychelys is missing the cranial characters.</p> </div>	https://treatment.plazi.org/id/4E7B8791CD55FD80FF42FB5117E58D78	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	GAFFNEY, EUGENE S;TONG, HAIYAN;MEYLAN, PETER A	GAFFNEY, EUGENE S, TONG, HAIYAN, MEYLAN, PETER A (2006): EVOLUTION OF THE SIDE-NECKED TURTLES: THE FAMILIES BOTHREMYDIDAE, EURAXEMYDIDAE, AND ARARIPEMYDIDAE. Bulletin of the American Museum of Natural History 300 (300): 1-698, DOI: 10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2, URL: http://dx.doi.org/10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2
4E7B8791CD55FD80FF42FEC817E48CBE.text	4E7B8791CD55FD80FF42FEC817E48CBE.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Proterochersis Fraas 1913	<div><p>Proterochersis</p> <p>This genus is described by Fraas (1913), with additions and a new shell reconstruction in Gaffney (1990). Although only known from the shell, the 20 or so specimens representing this species provide important information on the earliest pleurodires.</p> <p>Karl and Tichy (2000) have named a new taxon, ‘‘ Murrhardtia staeschei ’’, from the Late Triassic of Germany. This taxon is a junior synonym of Proterochersis robusta Fraas, 1913. Karl and Tichy mistakenly used Fraas’ reconstruction of the type, SMNS 12777 (Fraas, 1913: figs. 1, 2), as a figure of the actual type specimen for comparison, and they named a more complete specimen of Proterochersis robusta (unnumbered shell in the Carl Schweizer Museum, Murhardt, Germany) as a new taxon. SMNS 12777 has only the internal mold of the carapace, plus a partial plastron, while the Karl and Tichy shell is nearly complete. However, two of us (E.S.G., P.A.M.) have studied these specimens, as well as nearly two dozen other Proterochersis shells, and have concluded that they belong to a single species. The areas of overlap of the Proterochersis robusta type specimen and the type specimen of ‘‘ Murrhardtia staeschei ’’ are nearly identical.</p> </div>	https://treatment.plazi.org/id/4E7B8791CD55FD80FF42FEC817E48CBE	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	GAFFNEY, EUGENE S;TONG, HAIYAN;MEYLAN, PETER A	GAFFNEY, EUGENE S, TONG, HAIYAN, MEYLAN, PETER A (2006): EVOLUTION OF THE SIDE-NECKED TURTLES: THE FAMILIES BOTHREMYDIDAE, EURAXEMYDIDAE, AND ARARIPEMYDIDAE. Bulletin of the American Museum of Natural History 300 (300): 1-698, DOI: 10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2, URL: http://dx.doi.org/10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2
4E7B8791CD55FD34FD7FFE7816278D13.text	4E7B8791CD55FD34FD7FFE7816278D13.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Dortoka Lapparent de Broin and Murelaga 1996	<div><p>Dortoka</p> <p>This shell taxon was described by Lapparent de Broin and Murelaga (1999).</p> <p>Chelidae</p> <p>Monophyly of the Chelidae is well corroborated. Within-group relationships based on morphology (Gaffney, 1977b; Gaffney and Meylan, 1988) and molecules (Shaffer et al., 1997; Seddon et al., 1997; Georges et al., 1998; Krenz et al., 2005; Near et al., 2005) differ significantly, and the molecular phylogenies seem to be well supported. The molecular analyses tend to recognize separate Australian and South American clades, but these relationships become less certain when all chelid genera are represented in the dataset (Georges et al., 1998). We have not adopted a within-group cladogram for chelids, and we have therefore coded some characters as variable. Note that recent discoveries of Cretaceous chelids (Fuente et al., 2001; Lapparent de Broin and Fuente, 2001; Fuente, 2003; Bona and Fuente, 2005) support the morphology-based analyses.</p> <p>CHARACTER DESCRIPTIONS</p> <p>The characters chosen here include ones not only relevant for bothremydids but for all pleurodires, outside podocnemidids, and chelids. Although characters primarily resolving Proganochelys and all other turtles are included in the analysis, they are only referenced and briefly described, having been discussed elsewhere. The same format of headings used in Gaffney (1996) is used here. The history of use of particular characters in the literature is primarily taken from papers with actual datasets (i.e., Meylan, 1996; Tong et al., 1998; Lapparent de Broin and Murelaga, 1999; Fuente and Iturralde-Vinent, 2001) which explicitly show taxon distribution, although reference is also made to literature with more extensive character descriptions (i.e., Antunes and Broin, 1988; Lapparent de Broin and Werner, 1998; Lapparent de Broin, 2000a), even though they lack character matrices.</p> <p>These descriptions are also shown in the Character List (appendix 2) and their distributions are shown in the Data Matrix (appendix 3). In the Character List, the senior author has attempted to organize the characters by bone in the same order as in the Cranial Morphology sections. In order to keep track of which bone is involved, in the Character List each character is preceded by the abbreviation of the bone followed by the character name. However, AMNH editorial policy requires that when used as text these abbreviations must be spelled out. Therefore instead of ‘‘NA, nasal bones’’ the discussion below identifies the character as the more cumbersome ‘‘Nasal, nasal bones.’’ And so on.</p> <p>1. Nasal, nasal bones: present (Emydura) 5 0; absent (Pelusios) 5 1.</p> <p>Morphology: When present (fig. 6A), nasals make up the anteriormost part of the skull roof anterior to the orbits. Skull figures showing the morphology of nasal bones in the turtles in which they occur are in Gaffney (1979a). The absent condition is seen in figures 6B and 21A. See discussion of this character in cryptodires in Gaffney (1996).</p> <p>Primitive condition: Paired nasals are present throughout amniotes and are present in Proganochelys, most chelids, and primitive cryptodires.</p> <p>Homoplasy: There is good evidence that nasals have been lost independently within the Pleurodira and Cryptodira. Within the Pleurodira they are absent in all Pelomedusoides for which this portion of the skull is known. Among chelids they are absent or fused to the frontals only in the genus Chelus (Gaffney, 1979a: fig. 144).</p> <p>Discussion: The absence of nasal bones is a synapomorphy for Pelomedusoides. This character is used in Antunes and Broin (1988), Gaffney and Meylan (1988), Gaffney et al. (1991), Meylan (1996), and Lapparent de Broin and Werner (1998).</p> <p>2. Lacrimal, lacrimal bone: present (Proganochelys) 5 0; absent (Emydura) 5 1.</p> <p>See Gaffney (1990) and Gaffney et al. (1991) (also used in Gaffney and Meylan, 1988; and Rougier et al., 1995).</p> <p>3. Lacrimal, lacrimal foramen: present (Proganochelys) 5 0; absent (Pelusios) 5 1.</p> <p>See Gaffney (1990), Gaffney et al. (1991), and Gaffney and Kitching (1995) (also used in Gaffney and Meylan, 1988; and Rougier et al., 1995).</p> <p>4. Prefrontal, prefrontals meet on midline in dorsal view: no (Proganochelys) 5 0; yes (Pelusios) 5 1.</p> <p>Morphology: When nasals are present, nasal-frontal contact typically excludes midline contact of the prefrontals (fig. 6A). However, prefrontals are not always in contact when nasals are absent (e.g., Chelus, Gaffney, 1979a: fig. 144), and on occasion prefrontals may be in midline contact although nasals are present (e.g., Hydromedusa, Gaffney, 1979a: fig. 146). State 1 is seen in figure 6B–J.</p> <p>Primitive condition: The nasal-frontal contact to the exclusion of prefrontal midline contact in Proganochelys, most chelids, and primitive cryptodires suggests that prefrontals meeting on the midline represents a derived condition.</p> <p>Homoplasy: Except for Hydromedusa (Gaffney, 1979a, 1979c), none is known within pleurodires.</p> <p>Discussion: Prefrontals meeting on the midline is a synapomorphy for the Pelomedusoides. This character is used in Gaffney and Meylan (1988) and Gaffney et al. (1991).</p> <p>5. Prefrontal, preorbital skull broad: narrow (Galianemys) 5 0; very broad (Bothremys) 5 1.</p> <p>Morphology: The snout or preorbital region of turtles generally forms a wide angle of about 70–90 °. However, in some species the snout is greatly widened anteriorly, giving the skull a very broad outline in dorsal view (figs. 7, 136, 146). Many bones make up this region; we have arbitrarily chosen to treat this character under the prefrontal.</p> <p>Primitive condition: The snout of Proganochelys forms an angle of about 80 ° and those of primitive cryptodires and chelids are similarly uninflated, and this is presumed to be the primitive condition.</p> <p>Homoplasy: Araiochelys lies within the Bothremydini and it is much narrower than other Bothremydini (fig. 7E) and is a reversal from the very broad condition seen in other Bothremydini.</p> <p>Discussion: A wide snout, in excess of 80 °, is a synapomorphy for the Bothremydini.</p> <p>6. Prefrontal, anterior margin: straight, broadly convex margin in dorsal view (Pelomedusa) 5 0; narrow midline process, at least partially dividing nares (Bothremys) 5 1.</p> <p>Morphology: The dorsal margin of the apertura narium externa forms an anterior process on the midline, partially dividing the apertura (fig. 7G, H). In some bothremydids, such as Araiochelys (fig. 125D), the process almost completely divides the apertura.</p> <p>Primitive condition: Although the anterior margin is broadly convex in pelomedusids, it is relatively straight in chelids and euraxemydids.</p> <p>Homoplasy: This character has a CI of 0.33 for this dataset and has originated or been lost multiple times elsewhere within the Pleurodira.</p> <p>Discussion: The protrusion is present in Araiochelys and Bothremys within the Bothremydini. It is present only in Labrostochelys and Ummulisani, among the Taphrosphyini, suggesting that it appeared twice within the family. It helps to define the group Araiochelys, Bothremys, and Chedighaii within the Bothremydina. There is some ambiguity in identifying the degrees of protrusion. Comparing Bothremys cooki and some Galianemys specimens shows only a slight difference. As coded, it supports the (Araiochelys, Bothremys, Chedighaii) group.</p> <p>7. Prefrontal, prefrontal-palatine contact: widely separated (Galianemys) 5 0; closely spaced or in contact (Bothremys) 5 1.</p> <p>Morphology: Cryptodires generally have a large ventral process of the prefrontal that contacts the palatine posteriorly (Gaffney, 1979a: 73). However, in most pleurodires the descending process of the prefrontal is smaller and usually not in contact with the vomer or palatine. State 1 is seen through the orbit in Labrostochelys (fig. 193). In the taxa in which the bones are close but not in contact (e.g. Bothremys cooki, fig. 130A), there is no overlap in morphology with those taxa that have these bones widely separated.</p> <p>Primitive condition: Gaffney (1990: 37) reported a wide prefrontal-palatine contact in Proganochelys, so this contact appears to be primitive for turtles. However, the contact is absent in chelids other than an occasional Emydura (Gaffney,1979a: 73) and it is absent in pelomedusids, except for an occasional Pelusios (Gaffney, 1979a: 73), Araripemys, euraxemydids, Hamadachelys, and members of the Podocnemididae. This distribution suggests that the absence of this contact is primitive for the Bothremydidae.</p> <p>Homoplasy: Among the Pleurodira this contact occurs as a variant in some individuals of Pelusios and Emydura (Gaffney, 1979a: 73). These appearances occur independently of those within the Bothremydidae. The character occurs independently in the Bothremydini (Araiochelys, Bothremys, and Chedighaii) and in the Taphrosphyini (Labrostochelys).</p> <p>Discussion: In spite of homoplasy, this character helps resolve relationships within Bothremydini.</p> <p>8. Prefrontal, prefrontal-vomer contact: absent (Proganochelys) 5 0; present (Pelusios) 5 1.</p> <p>This character is used by Gaffney and Meylan (1988), Gaffney (1990), Gaffney et al. (1991), and Rougier et al. (1995).</p> <p>9. Prefrontal, fissura ethmoidalis: very wide (Proganochelys) 5 0; narrower (Pelusios) 5 1.</p> <p>See Gaffney (1990).</p> <p>10. Prefrontal, prefrontal-parietal contact: absent (Galianemys) 5 0; present (Phosphatochelys) 5 1.</p> <p>Morphology: In most turtles the skull roof is formed by paired prefrontals, frontals, and parietals, with the frontals normally intervening between the other pairs. Prefrontal-parietal contact occurs when the frontals are reduced (fig. 196) or absent (fig. 204).</p> <p>Primitive condition: In the skull roof of Proganochelys and other outgroups this contact is absent (Gaffney, 1990: figs. 16, 114), as is the case in all cryptodires, chelids, pelomedusids, and podocnemidids. Absence of this contact is clearly primitive.</p> <p>Homoplasy: We are not aware of any homoplasy in this character. When the frontals are greatly reduced in cryptodires (i.e., Platysternon), the postorbitals intervene between the prefrontals and parietals (Gaffney, 1979a: 221).</p> <p>Discussion: This unique feature is a synapomorphy for the two genera Ummulisani and Phosphatochelys.</p> <p>11. Frontal, orbits facing upward: orbits facing more laterally (Galianemys) 5 0; orbits facing more dorsally (Bothremys) 5 1.</p> <p>Morphology: In most turtles the skull roof forms a horizontal table, with the maxillae forming nearly vertical walls and the orbits open laterally in a vertically oriented face. In Bothremys and Chedighaii (figs. 7, 127) there is very little change in slope from the roof and the face of the skull so that the orbits face dorsally and only slightly laterally.</p> <p>Primitive condition: The orbits of Proganochelys are quite vertically oriented (Gaffney, 1990: figs. 16, 114). In primitive cryptodires, chelids, pelomedusids, and podocnemidids, orientation is variable but generally more vertical than horizontal. Thus, the more vertical orientation is considered primitive.</p> <p>As coded here, the primitive condition includes a wide variety of orbital orientations. However, efforts to specify states, such as nearly vertical, laterally facing orbits as found in Phosphatochelys and Azabbaremys, were abandoned due to the difficulty of distinguishing gradational conditions in other Taphrosphyini and Cearachelyini.</p> <p>Homoplasy: Within the Bothremydidae no forms other than Bothremys and Chedighaii have dorsally facing orbital openings. However, Araripemys has the closest approach to this condition, and within chelids the tribe Chelini of Gaffney (1977b) has dorsally facing orbits.</p> <p>Discussion: The horizontal orbits of Bothremys and its friends are presumably related to the great anterior expansion and flattened shape of the skull. This character is a synapomorphy for Bothremys + Chedighaii.</p> <p>12. Frontal, foramen interorbitale: high (Galianemys) 5 0; low (Bothremys) 5 1.</p> <p>Morphology: The foramen interorbitale is the opening medial to the orbit defined by the sulcus olfactorius dorsally, the descending process of the parietal posteriorly, and the vomer and dorsal surface of the palatal elements ventrally (fig. 21). In most turtles this opening is round or oval in shape (Gaffney, 1979a). In the Bothremydini the foramen interorbitale is low and reduced in height by a high palate and low sulcus olfactorius (fig. 144).</p> <p>Primitive condition: The foramen interorbitale is quite tall and rounded in Proganochelys (Gaffney, 1990). It is generally broadly rounded in cryptodires and all pleurodires other than Chelus and members of the Bothremydini.</p> <p>Homoplasy: Independent acquisition of this character has occurred in Chelus; it has no homoplasy within Pelomedusoides.</p> <p>Discussion: Although the low foramen interorbitale is diagnostic of the Bothremydini, the character is indeterminable in some Bothremydini (Polysternon, Zolhafah, Bothremys arabicus, and Chedighaii barberi). Examination of the endocast (YPM PU 12951) of a presumed C. barberi shows that it was low.</p> <p>13. Parietal, quadratojugal-parietal contact: absent (Proganochelys) 5 0; present, quadratojugal large and anterior to quadrate (Euraxemys) 5 1; present, quadratojugal small and dorsal to quadrate (Phosphatochelys) 5 2.</p> <p>Morphology: In the skull roof of turtles, the parietal is normally separated from the jugal and quadratojugal by an elongate postorbital that reaches the temporal margin of the skull. In some forms, contact of the quadratojugal and parietal prevents posterior exposure of the postorbital on the temporal margin. This can occur due to a very large quadratojugal that reaches the cheek emargination and extends posteromedially over the quadrate and meets the parietal medially (state 1, figs. 42, 47), or by a laterally enlarged parietal that meets a small quadratojugal that lies dorsal to the quadrate and does not reach the cheek emargination (state 2, figs. 178, 183, 185). We treat these two morphologies as independent states of the same character.</p> <p>Primitive condition: It is clear that the primitive condition for the turtle skull roof is to have the postorbital separating the parietal and quadratojugal. The postorbital either reaches the squamosal (Proganochelys, Kayentachelys, Pleurosternon, and other primitive cryptodires; Gaffney, 1990) or the temporal margin of the skull (Polycryptodira, Pelomedusidae, Araripemys). A parietal-quadratojugal contact is clearly a derived condition.</p> <p>Homoplasy: The presence of a quadratojugal-parietal contact with a large quadratojugal (state 1) occurs in Euraxemydidae and Podocnemididae + Hamadachelys. The most parsimonious cladogram shows these as independent acquisitions.</p> <p>Discussion: State 1 supports Euraxemydidae and, independently, Podocnemididae + Hamadachelys. State 2, quadratojugal-parietal contact with a large parietal and small quadratojugal, occurs in Taphrosphys, Ummulisani, Labrostochelys, and Phosphatochelys and is without homoplasy in the subgroup of Taphrosphyini that it defines.</p> <p>This character is used in Gaffney and Meylan (1988) and Lapparent de Broin (2000a).</p> <p>14. Parietal, temporal emargination: absent, slight (Proganochelys) 5 0; extreme (Kurmademys) 5 1; intermediate (Galianemys) 5 2.</p> <p>Morphology: The fossa temporalis superi- or of turtles contains the adductor mandibulae and is primitively roofed over by the skull roof elements, particularly the parietal, squamosal, postorbital, and quadratojugal. Emargination of this skull roof both posteriorly (temporal emargination) and laterally (cheek emargination) is a common theme in turtle evolution (Gaffney, 1979a: 83–86).</p> <p>In Pelomedusoides the temporal emargination varies a great deal, and dividing this variation into a suite of characters that have a good chance of being homologous is difficult due to the simple morphology involved. We have chosen to identify three conditions in order to obtain some information from this morphologic area. The most extreme emargination, state 1, is relatively easy to recognize. In state 1 only a narrow bridge of bone is present between the orbit and the temporal margin, as found in pelomedusids, Araripemys (fig. 26), and the tribe Kurmademydini (figs. 5, 54, 65). Although it is somewhat subjective, the degree of emargination seen in the tribe Cearachelyini (fig. 81), state 2, is defined as intermediate between state 1 and the remaining bothremydids. In state 2 the otic chamber is fully exposed and the bone (postorbital) between the temporal margin and orbit is at least twice as long as in state 1. The principal ambiguity is differentiating state 0 from state 2 in some Bothremydini (such as Bothremys maghrebiana and Chedighaii, which have most but not all of the otic chamber exposed), and the degree is partially dependent on how the skull is oriented.</p> <p>Primitive condition: Proganochelys (Gaffney, 1990) has a complete skull roof with no emargination. In the Chelidae (Gaffney, 1979c) temporal emargination is slight or absent except in those cases where cheek emargination appears to have joined with temporal emargination. In other outgroups to the Bothremydidae, temporal emargination is extreme (Pelomedusidae, Araripemys), moderate (Hamadachelys), or variable (Podocnemididae). The extensive skull roof of the Bothremydini and the Taphrosphyini is interpreted as a reversal.</p> <p>Homoplasy: This is a character in which there is a great deal of homoplasy within cryptodires, both in the form of independent acquisition of states and as reversals. The presence of extensive skull roofs in primitive cryptodires such as Kayentachelys, Pleurosternon, Glyptops, and most baenids (Gaffney, 1979b) also suggests that well-developed emargination has occurred independently in pleurodires and cryptodires. Similarly, the presence of well-roofed forms in the Meiolaniidae, Chelonioidea, Chelydridae, Podocnemididae, and Bothremydidae suggests that secondary redevelopment of the skull roof has occurred on multiple occasions.</p> <p>The emargination states as scored here show homoplasy in state 1, but none in state 2. The extreme temporal emargination of state 1 has arisen three times in the MPC. The conditions in Kurmademys and Sankuchemys are very similar, but the skulls of Araripemys and pelomedusids are not, and the emargination is not identical.</p> <p>State 2, intermediate or moderate emargination, is not as subjective as it sounds and is recognizable within the Pelomedusoides. The degree of emargination is very similar in Cearachelys and Galianemys, supporting the monophyly of the Cearachelyini.</p> <p>Discussion: The principal difficulty with this character is the primitive condition, state 0, a well-roofed skull. The morphology of Proganochelys and the Taphrosphyini, for example, is not even similar and is questionably homologous on morphological grounds alone. Yet the well-roofed skulls of the Taphrosphyini and the Bothremydini are similar and probably homologous considering that the two immediate outgroups, the tribes Cearachelyini and Kurmademydini, have distinctly greater degrees of temporal emargination.</p> <p>This character is used in many papers (see Gaffney and Meylan, 1988; Lapparent de Broin and Werner, 1998; Lapparent de Broin and Murelaga, 1999; Lapparent de Broin, 2000a).</p> <p>15. Parietal, parietal-squamosal contact: present (Proganochelys) 5 0; absent (Pelusios) 5 1.</p> <p>Morphology: This condition (state 1) is related to the degree of posterior skull roof (temporal) emargination, and it is seen in most Pelomedusoides (figs. 6–8).</p> <p>Primitive condition: The contact is present (state 0) in Proganochelys, Kayentachelys and other primitive cryptodires, and chelids and is considered the primitive condition.</p> <p>Homoplasy: Skull roof emargination is homoplastic in this analysis (see character 14), but the widespread loss of the squamosal-parietal contact in Pelomedusoides suggests that at least the development of temporal emargination to the point of parietal-squamosal separation is synapomorphic for the group. Dirqadim is the only reversal.</p> <p>Discussion: It is possible to put this character as a state in character 14, temporal emargination. However, that character seeks to identify the most emarginate extremes, while this one deals with the other end of the spectrum, the most minimal emargination.</p> <p>This character is used in Gaffney et al. (1991).</p> <p>16. Parietal, parietal contacts pterygoid at base of processus trochlearis pterygoidei: absent (Pelusios) 5 0; ventral process of parietal reaches pterygoid on lateral side of sulcus palatinopterygoideus (Bothremys) 5 1.</p> <p>Morphology: A ventral process of the parietal contacts the pterygoid lateral to the sulcus palatinopterygoideus near the base of the processus trochlearis pterygoidei (fig. 62).</p> <p>Primitive condition: In Proganochelys and in all of the pleurodiran outgroups to the Bothremydidae, parietal-pterygoid contact is restricted to the processus inferior parietalis.</p> <p>Homoplasy: This contact is not known to occur outside of the Bothremydidae. However, within the Bothremydidae it has arisen three times in the MPC. There is no indication of different morphologies for the separate occurrences.</p> <p>Discussion: Unfortunately this character requires a well-preserved and well-prepared skull for its determination, and the inadequate preservation among the Taphrosphyini in particular limits its use. As known, however, it supports Bothremys + Chedighaii.</p> <p>17. Parietal, sulcus palatinopterygoideus: absent (Proganochelys) 5 0; present and high (Galianemys) 5 1; present and low due to thick parietal and postorbital roof (Bothremys) 5 2.</p> <p>Morphology: The sulcus palatinopterygoideus (figs. 23, 25, 62, 78) is the space found only in pleurodires between the fossa orbitalis and the fossa temporalis, with its medial wall formed by the processus inferior parietalis plus crista pterygoidea and its lateral wall formed by the processus trochlearis pterygoidei. We adopt the term ‘‘sulcus palatinopterygoideus’’ following Antunes and Broin (1988: figs. 3, 4, 8). However, they also used a synonym ‘‘gouttière ptérgoidienne’’. In Lapparent de Broin and Werner (1998) they used ‘‘pterygoid sulcus’’ as well as ‘‘sulcus palatinopterygoideus’’. Schumacher (1954: fig. 25; 1955a: figs. 1, 3) used the broader term ‘‘orbitale Pterygoideusrinne’’ or ‘‘orbitaler Pterygoideuskanalrinne’’ for this space in pleurodires. However, he also used the term for the dorsal surface of the pterygoid in cryptodires (Schumacher, 1955a: fig. 6), so it is clearly not the restricted usage we employ here. The sulcus palatinopterygoideus is defined laterally by the processus trochlearis pterygoidei and is therefore found only in taxa with this structure, that is, pleurodires.</p> <p>The two conditions of the sulcus recognized here are the more common: the relatively high sulcus (state 1, fig. 78) and the more restricted, relatively low condition (state 2, figs. 130, 279), formed by a thicker and lower parietal, with some participation of postorbital, as seen in Bothremys and Chedighaii hutchisoni.</p> <p>Primitive condition: For turtles, the absence of this structure is primitive. Within the Pleurodira, the higher condition of the sulcus palatinopterygoideus is present in chelids, pelomedusids, and euraxemydids and can be considered primitive.</p> <p>Homoplasy: There is no homoplasy in the analysis for the presence of the sulcus palatinopterygoideus, which is a pleurodiran synapomorphy (fig. 297). However, a low sulcus palatinopterygoideus also occurs in some Podocnemididae as well as within the Bothremydini (fig. 297). The conditions do not appear to be distinguishable morphologically.</p> <p>Discussion: This character is not the same as simply having a low skull. Araripemys and Labrostochelys have very low skulls, but they have a relatively high sulci palatinopterygoideus. The degree of dorsal restriction of the sulcus is not clear. Rosasia could be interpreted as having a lower sulcus than that in Cearachelyini but higher than that in Bothremys. We have chosen to recognize only the more clearly identifiable extreme condition. Several key taxa, Araiochelys and Zolhafah, among Bothremydini, are not well enough preserved to code this character and that limits its usefulness.</p> <p>18. Parietal, enters orbital margin: no (Galianemys) 5 0; yes (Phosphatochelys) 5 1.</p> <p>Morphology: The dorsal plate of the parietal enters the posteromedial margin of the orbit in Rhothonemys, Ummulisani, and Phosphatochelys (figs. 196, 204, 208). In ventral view, the parietal forms part of the fossa nasalis roof.</p> <p>Primitive condition: In all outgroups and in Euraxemydidae and Cearachelyini, the parietal does not enter the orbital margin.</p> <p>Homoplasy: No homoplasy seen in the MPC.</p> <p>Discussion: This character occurs only in three taxa in Pelomedusoides: Rhothonemys, Ummulisani, and Phosphatochelys. The shape of the parietal itself is very similar in the three taxa, but some of the surrounding elements differ. In Phosphatochelys and Ummulisani the frontal is very small (or absent) and does not enter the orbital margin due to a prefrontal-parietal contact. In Rhothonemys the frontal is larger, widely enters the orbital margin, and there is no prefrontal-parietal contact. However, the parietals of all three taxa also agree in being relatively farther forward in the skull roof than in any other Pelomedusoides, so that they form a significant part of the fossa orbitalis roof, also in contrast to other Pelomedusoides.</p> <p>19. Supratemporal, supratemporal bone: present (Proganochelys) 5 0; absent (Pelusios) 5 1.</p> <p>See Gaffney (1990), Gaffney et al. (1991), and Rougier et al. (1995).</p> <p>20. Jugal, jugal retracted from orbital margin: jugal enters orbit (Pelusios) 5 0; jugal slightly retracted (Cearachelys) 5 1; jugal widely retracted (Galianemys) 5 2.</p> <p>Morphology: In Cearachelys (figs. 71E, 78) the postorbital has a long ventral process extending along the orbital margin that nearly meets the maxilla (Cearachelys, Postorbital). There is some variation in degree and preservation, but this condition (state 1) occurs in all three Cearachelys skulls. In the two species of Galianemys (figs. 81, 89), the postorbital and maxilla widely meet, completely separating the jugal from the orbital margin (state 2).</p> <p>Primitive condition: Substantial jugal exposure in the orbital margin is clearly the primitive condition, as seen in Proganochelys (Gaffney, 1990: fig. 16) and nearly all pleurodires.</p> <p>Homoplasy: This feature appears to have occurred independently in several lineages of cryptodires, but there is no indication of homoplasy within the Pleurodira (fig. 298).</p> <p>Discussion: This character is run ordered in the preferred analysis, with state 1, partial retraction, the primitive state relative to state 2, complete retraction. The additive nature of this character could also be expressed as two states only: no retraction, and at least partial jugal retraction present. When the analysis is run with the three states ordered, the character unites the Cearachelyini (with the partial condition) and the genus Galianemys (with full retraction). When the character is run unordered, the same MPC results (fig. 298).</p> <p>21. Jugal, jugal narrow dorsoventrally: absent (Bothremys) 5 0; present (Taphrosphys, Labrostochelys) 5 1.</p> <p>Morphology: In Taphrosphys and Labrostochelys (figs. 178, 185, 190) the lateral exposure of the jugal is long horizontally and short vertically. Although there is a contribution to the orbital margin, the height of the bone is significantly less than in other Taphrosphyini and in turtles in general.</p> <p>Primitive condition: The jugal in Proganochelys, most chelids, pelomedusids, Araripemys, euraxemydids, and podocnemidids has a large exposure on the cheek.</p> <p>Homoplasy: Reduced jugal exposure on the cheek also occurs in some chelids with well-developed cheek emargination, such as Hydromedusa and Platemys, and in some testudinoids (Cuora, Melanochelys, Rhinoclemmys, Terrapene, Gopherus, Kinixys, and Psammobates). Within the Pelomedusoides, there is no evidence of homoplasy. In the MPC, the character occurs independently in Labrostochelys and Taphrosphys.</p> <p>Discussion: The character occurs only in members of the Taphrosphyini. It unites two species of Taphrosphys, T. ippolitoi and T. congolensis; it is not known in T. sulcatus.</p> <p>22. Jugal, jugal-quadrate contact: absent (Bothremys) 5 0; present (Azabbaremys) 5 1.</p> <p>Morphology: In the Taphrosphyini the cheek is relatively short with a dorsally retracted quadratojugal, allowing the jugal to contact the large quadrate (figs. 178, 185, 196).</p> <p>Primitive condition: Although the sutures in this area are not definite in Proganochelys, contacts observed in most Casichelydia, including primitive cryptodires and pleurodires, show that separation of these elements by the quadratojugal is the primitive condition for Pleurodira.</p> <p>Homoplasy: Although there is no homoplasy in the Bothremydidae, this feature occurs within the Podocnemididae in Peltocephalus and Erymnochelys. It occurs with a large jugal crossing the area where cheek emargination normally occurs; the quadratojugal is not reduced in size. In the Taphrosphyini with this contact, the quadratojugal is small and dorsally located. Jugal-quadrate contact also occurs in the cryptodire Archelon.</p> <p>Discussion: The jugal-quadrate contact is a diagnostic character of the Taphrosphyini in the MPC, but the character is determinable with certainty in only 5 of 11 taxa, although Labrostochelys probably has it. The contact also differs among the known taxa. In Azabbaremys it is a wide contact with both bones relatively thick. In Phosphatochelys the bones are very thin and the contact could almost be kinetic.</p> <p>23. Jugal, exposure on triturating surface: none (Pelusios) 5 0; large exposure visible in ventral view (Bothremys) 5 1.</p> <p>Morphology: The upper triturating surface in turtles is made up mostly by the maxilla with an anterior contribution by the premaxilla. In many forms there is also some contribution posteriorly or posteromedially from the palatine. However, contribution by the jugals to the triturating surface is rare. Character state 1 is the ventral exposure of the jugal on the triturating surface in palatal view (figs. 10, 130). A small amount of jugal may be exposed, as in Cearachelys (fig. 77), but this is not the character as delimited here.</p> <p>Primitive condition: In Proganochelys, all primitive cryptodires, chelids, pelomedusids, euraxemydids, and podocnemidids the jugals are excluded from the triturating surface.</p> <p>Homoplasy: The MPC shows this character as a synapomorphy of the Bothremydina, with a reversal in Chedighaii. The character also occurs independently in the Taphrosphyini in CNRST-SUNY 199, an undescribed form from Mali.</p> <p>The only taxon outside of the Bothremydidae in which jugal participation in the triturating surface is known is Sandownia (Meylan et al., 2000) and a probably related undescribed form from the Paleocene of Morocco. In Sandownia jugal participation is long and narrow and lateral to the maxilla and pterygoid. There is no jugal-palatine contact on the triturating surface as in bothremydids.</p> <p>Discussion: Within the Cearachelyini, a slightly exposed jugal occurs in Cearachelys and one species of Galianemys, G. whitei, but not in the other species, G. emringeri. The three skulls of Cearachelys (fig. 77) show some variation in the degree of jugal exposure, suggesting that this character is one of degree rather than the all or none used in the character coding. Nonetheless, we have coded the small exposure as ‘‘0’’ and only recognized the more extreme condition as the character.</p> <p>This character is used in Meylan (1996), Lapparent de Broin and Werner (1998), and Tong et al. (1998).</p> <p>24. Squamosal, posterior projection: absent (Galianemys) 5 0; present, projecting posteriorly, forming distinct process (Bothremys) 5 1.</p> <p>Morphology: In the Bothremydini and some Taphrosphyini, the squamosal forms a posterior process that extends well posteri- or to the opisthotic (figs. 7, 101, 102, 122, 123).</p> <p>Primitive condition: In the outgroups, either there is no projection (Proganochelys, euraxemydids) or the opisthotic projects no farther than the squamosal (chelids, pelomedusids). In most Bothremydidae (except Bothremydini and Labrostochelys and CNRST-SUNY 199), the squamosal is even with or projects only a short distance beyond the opisthotic.</p> <p>Homoplasy: This character occurs in Labrostochelys and CNRST-SUNY 199 outside the Bothremydini, although it is longer and deeper in Labrostochelys, consistent with the hypothesis that it is nonhomologous.</p> <p>Discussion: The character is a synapomorphy for the Bothremydini but remains uncertain in several taxa for which this part of the skull is poorly known.</p> <p>Another character, character 102, processus paroccipitalis not projecting beyond squamosal, is distinct from this one. In the opisthotic character, the processus paroccipitalis is very similar in all Bothremydidae; it is relatively small compared to those in outgroups like pelomedusids. The squamosal projection is present with a small opisthotic.</p> <p>25. Squamosal, posteroventral vertical flange: absent (Galianemys) 5 0; present (Labrostochelys) 5 1.</p> <p>Morphology: The squamosal forms the posterolateral corner of the skull posterior to the quadrate. It is generally a cone-shaped bone with the hollow of the cone contributing to the antrum postoticum if one is present. In Proganochelys the antrum postoticum is absent and the squamosal is a simple curved plate with a nearly flat ventral surface. When the character is present, the flange (figs. 168, 169, 172, 177–209, 287) is a thin sheet of bone running anteroposteriorly on the ventral surface of the squamosal. It appears to be related to the attachment of the depressor mandibulae musculature.</p> <p>Primitive condition: The squamosal flange is absent in Proganochelys and all outgroups.</p> <p>Homoplasy: None observed (fig. 299).</p> <p>Discussion: The ventral flange developed as a vertical plate on the squamosal is unique to a monophyletic group (fig. 299) within the subtribe Taphrosphyina: Taphrosphys, Labrostochelys, Ummulisani, Rhothonemys, and Phosphatochelys.</p> <p>26. Squamosal, lateral tubercle: absent (Galianemys) 5 0; present (Labrostochelys) 5 1.</p> <p>Morphology: At the posterodorsal edge of the cavum tympani in Taphrosphys, Labrostochelys, Ummulisani, and Phosphatochelys is a small tubercle produced by the squamosal that is directed laterally and ventrally along the suture with the quadrate (fig. 287). The tubercle may be at the posterior edge of the scale covering the cavum tympani. Posterior and ventral to the tubercle, the bone trends medially and was presumably covered by some part of the depressor mandibulae.</p> <p>Primitive condition: The tubercle is absent in all outgroups.</p> <p>Homoplasy: None apparent.</p> <p>Discussion: The function of this peculiar structure is unknown. It appears to mark the division between the scaled surface and the muscular covering.</p> <p>27. Postorbital, fossa orbitalis posterior enlargement: absent (Galianemys) 5 0; present (Bothremys) 5 1.</p> <p>Morphology: The fossa orbitalis of bothremydids is well defined by bone: the postorbital and jugal posteriorly, the postorbital and parietal dorsally, and the maxilla and palatine ventrally. In many bothremydids, the internal fossa is much larger than the orbital rim, and some of the bones form pockets or concavities that seem to be significantly larger than a spherical eyeball would require (fig. 144). Although there is some variation in the extent of this enlargement and which bones form it, we use a single character state to treat it. All of the taxa that have the character have a postorbital forming the septum orbitotemporale distinctly posterior to the orbital rim (figs. 211, 278), and some have a more pronounced ventral concavity formed by the maxilla (fig. 211) as well. Even those Taphrosphyini that have a small or mostly absent septum orbitotemporale have ridges on the parietal (fig. 211), which indicate the position of the posterior limits of the fossa orbitalis.</p> <p>Primitive condition: The pelomedusids (fig. 25) and chelids (Gaffney, 1979a: fig. 55) show the primitive condition of a fossa orbitalis close to the size of the orbital rim.</p> <p>Homoplasy: The condition may be a synapomorphy for the Bothremydidae with loss in Cearachelys, and within the Taphrosphyini in the MPC.</p> <p>Discussion: The identification of this character in Chedighaii barberi is based on the whole skull endocast YPM PU 12951 (figs. 166, 167), also described by Gaffney (1977b).</p> <p>The principal difficulty with this character is that it may be related to relative skull/orbit size. Skulls with relatively small orbital openings (e.g., Bothremys) may have a larger fossa orbitalis than skulls with relatively large orbits (e.g., Phosphatochelys). Nonetheless, identification of the character is based on the position of the ridges, particularly parietal and postorbital. Therefore, both Phosphatochelys and Bothremys are identified as having this character.</p> <p>28. Postorbital, septum orbitotemporale: absent (Proganochelys) 5 0; postorbital wall present (Galianemys) 5 1; postorbital wall at least partially open (Phosphatochelys) 5 2.</p> <p>Morphology: In pleurodires the posterior wall of the fossa orbitalis formed mostly by the jugal, palatine, and postorbital is a distinct structure (state 1), the septum orbitotemporale (figs. 23, 25, 43, 78). Proganochelys and cryptodires lack this wall (state 0). In some Taphrosphyini (T. congolensis, Phosphatochelys, Azabbaremys) this wall is reduced and mostly open (state 2; fig. 300). In this state (fig. 279), the ventral part of the postorbital is missing, lacking the palatine contact, and much of the jugal vertical component is reduced. The sulcus palatinopterygoideus is not defined laterally except for the pterygoid portion of the processus trochlearis pterygoidei. The partially open condition of this wall in the Taphrosphyini is a different condition from that in Proganochelys and cryptodires, as a portion of the postorbital wall and the sulcus palatinopterygoideus is still determinable in every pleurodire.</p> <p>Primitive condition: For pleurodires, a well-developed septum orbitotemporale is primitive (fig. 300). The septum orbitotemporale is part of the complex forming the processus trochlearis pterygoidei and the sulcus palatinopterygoideus (figs. 23, 25), all pleurodiran synapomorphies.</p> <p>Homoplasy: None known. Some cryptodires (e.g., trionychids; Gaffney, 1979a: fig. 144) may develop a partial wall along the posterior orbital rim, but it is clearly morphologically distinct from the pleurodiran condition.</p> <p>29. Postorbital, size: relatively short (Euraxemys) 5 0; relatively long (Galianemys) 5 1.</p> <p>Morphology: Considering the simple nature of the character definitions and the relatively large amount of variation in pleurodire skull roofs, this character may seem at first to be useless. However, there is an objective kernel in all this corn. The short postorbital, either entering the temporal margin (fig. 6B, F) or being bordered by the quadratojugal-parietal contact (fig. 6D, E), appears qualitatively distinguishable from the long, narrow postorbital of the Cearachelyini, Bothremydini, and Azabbaremys (figs. 6H–J, 7A, B, E, H–J, 8J).</p> <p>Primitive condition: The short postorbital occurs in the outgroups Proganochelys, chelids, pelomedusids, and Araripemys. Primitively, the postorbital was both short and not exposed by emargination. Exposure due to temporal emargination is treated elsewhere.</p> <p>Homoplasy: The longer than wide postorbital (state 1) appears only once within the Bothremydidae, but it is reversed within the Taphrosphyini for the Taphrosphys -Labrostochelys-Ummulisani-Phosphatochelys group. However, it also occurs in the Cryptodira.</p> <p>Discussion: Interestingly, the long, narrow postorbital within Bothremydidae occurs along with a well-roofed skull lacking an extensive temporal emargination. The Kurmademydini have a short postorbital, because they are extensively emarginated. One might speculate that this was the primitive Bothremydidae condition and that the elongate postorbital is correlated with the presumably re-evolved roofed skull found in all other bothremydids.</p> <p>This character is used in Meylan (1996), Tong et al. (1998), and Lapparent de Broin (2000b).</p> <p>30. Premaxilla, protrudes anteriorly beyond labial ridge: no, or slightly (Galianemys) 5 0; yes, in ventral view projects anteriorly (Bothremys) 5 1</p> <p>Morphology: The premaxilla, seen in ventral view, projects anteriorly beyond the labial ridge (figs. 10E, G–I, 11F, G, J).</p> <p>Primitive condition: A vertical or slightly inclined wall of the premaxilla between the labial ridge and the apertura narium externa is present in Proganochelys (Gaffney, 1990: fig. 27) and nearly all turtles and represents the primitive condition.</p> <p>Homoplasy: This character has a CI of 0.20, showing that it has a lot of homoplasy. However, there are three independent origins within the Taphrosphyini alone and only one in the Bothremydini. In the Bothremydini the premaxilla and maxillae have similar anterior protrusions beyond the labial ridge of the triturating surface. In Labrostochelys there is a long triangular projection of the premaxilla that is unlike any morphology known in any fossil or living turtle. Other Taphrosphyini have thick premaxillae, different from those in the Bothremydini. What is treated as one character could be argued to be different character states rather than one.</p> <p>Discussion: Although Chedighaii hutchisoni completely lacks the premaxillae, the receded prefrontals and inclined maxillae strongly suggest that the premaxilla was protruding. We have coded this taxon as ‘‘?’’ anyway, but it is nice to see that the MPC has decided Chedighaii should have a protruded premaxilla.</p> <p>31. Premaxilla, midline depression: absent, shallow, or indistinct (Euraxemys) 5 0; distinct and wide (Bothremys kellyi) 5 1; distinct and narrow (Rosasia) 5 2.</p> <p>Morphology: When the lingual ridge of the triturating surface is well defined and extends onto the premaxillae, a midline depression or concavity between the pair of ridges is sometimes formed on the triturating surface of the premaxilla. In Bothremydidae this depression is usually deep and well defined. It may be very broad, widening posteriorly as in Kurmademys, Zolhafah, Bothremys kellyi, and B. arabicus (state 1, figs. 9F, 10C, F, I) or it may be narrow, with essentially parallel sides as in Bothremys cooki, B. maghrebiana, Rosasia, and Araiochelys (state 2, fig. 10D, E, G, H).</p> <p>Primitive condition: In Proganochelys the lingual ridge does not extend up onto the triturating surface of the premaxilla. This is also the case in many pleurodires, including chelids, pelomedusids, Araripemys, euraxemydids, and most podocnemidids (a lingual ridge is present in Erymnochelys and Peltocephalus). These premaxillary depressions are generally absent in cryptodires. Similar depressions are seen only in cryptodires with multiple ridges on the triturating surface (e.g., Meiolania, Geochelone, Kachuga) in which they are formed at least in part by lateral accessory ridges of the triturating surface.</p> <p>Homoplasy: In the MPC the deep, wide midline concavity (state 1) occurs as a synapomorphy for Bothremydidae, but there are a number of reversals. State 1 is lost within the Bothremydini, but re-evolves in Chedighaii and in Bothremys arabicus and B. kellyi. There is also a reversal of the wide condition within Taphrosphyini where Azabbaremys loses the concavity (state 0) and Labrostochelys acquires a narrow one (state 2).</p> <p>Discussion: The extremes of this character, states 1 and 2, are easily recognized, but because it is a gradational character, intermediate stages are a problem. As with a number of these more subjective, gradational characters, the senior author has chosen to try recognizing just the most extreme conditions as states and to ignore the variation between them. However, this can be considered too subjective in some cases. Deleting this character from the analysis has a significant effect on the MPC, so this issue is important. When this character is deleted, the result is a loss of resolution for the four species in Bothremys, which become a multichotomy with Chedighaii, and a loss of resolution for Zolhafah and Rosasia, which become a multichotomy with the remaining Bothremydina. These are obviously poorly supported nodes and it is worth looking at the character in more detail. The taxa that it resolves in Bothremys have the character states clearly recognized. B. kellyi and B. arabicus have distinctly wide median depressions, and B. cooki and B. maghrebiana do have distinctly narrow ones. It is outside the Bothremydina that coding the depressions becomes more subjective. Rather than delete the character entirely from the dataset, it seems better to use it in the analysis and present the alternative cladogram (fig. 290).</p> <p>The midline space between the lateral triturating surfaces seen in state 1 is reduced in state 2, perhaps by increasing durophagy within the clades in which state 2 occurs.</p> <p>This character is used in Antunes and Broin (1988) and is probably equivalent to the ‘‘anterior palatine sulcus’’ of Lapparent de Broin and Werner (1998).</p> <p>32. Premaxilla, midline dorsal process: present, meeting nasals (Proganochelys) 5 0; absent or low (Galianemys) 5 1; present, at least partially separating nares (Araiochelys) 5 2.</p> <p>Morphology: In Bothremys, Araiochelys, Rhothonemys, and Labrostochelys the apertura narium externa is at least partially divided by a dorsal process, half formed by each premaxilla, which rises from the lower margin of the apertura (figs. 130, 141, 143). In Araiochelys (fig. 125D) this almost completely divides the apertura.</p> <p>Primitive condition: Proganochelys has a dorsal premaxillary process, as in many other amniotes, which completely divides the apertura narium externa. However, chelids, pelomedusids, euraxemydids, Araripemys, podocnemidids, Cearachelyini, and Kurmademydini all lack one, and this is the presumed primitive condition for Pleurodira.</p> <p>Homoplasy: The dorsal premaxillary process is lost once in the MPC, at the Casichelydia node, and reversed twice, within the tribes Bothremydini and within Taphrosphyini.</p> <p>Discussion: An earlier version of this character was ‘‘figure eight shaped apertura narium externa’’, but this version may be a little more objective. There are many stories in the nose of pleurodires, and this is just one of them.</p> <p>This character is used in Gaffney and Kitching (1995) and Rougier et al. (1995).</p> <p>33. Premaxilla, dorsal sulcus: smooth surface (Bothremys) 5 0; sulcus parallel to margin of apertura narium externa (Phosphatochelys) 5 1.</p> <p>Morphology: A narrow, parallel-sided trough occurs along the anterior edge of the apertura narium externa on the dorsal surface of the premaxilla in Taphrosphys congolensis, T. ippolitoi, and Phosphatochelys (fig. 279). The sulcus has a variable number of foramina in its floor that extend ventrally into the premaxilla. The sulcus presumably held an artery or vein.</p> <p>Primitive condition: Neither Proganochelys nor any of the pleurodiran outgroups have this sulcus. The floor of the fossa nasalis in this area in various pleurodires may have a lip and scattered foramina, but not this well-defined sulcus.</p> <p>Homoplasy: None known.</p> <p>Discussion: This is a fairly ‘‘minor’’ character that intuitively seems particularly liable to individual variation, but it occurs only once in the MPC and does help define a group within the Taphrosphyina.</p> <p>34. Maxilla, triturating surfaces: relatively narrow, parallel sides (Taphrosphys) 5 0; triangular, wider posteriorly than anteriorly (Galianemys) 5 1: triangular, very wide posteriorly (Bothremys) 5 2.</p> <p>Morphology: The bothremydid tribes Cearachelyini, Kurmademydini, and Bothremydini all have wide triturating surfaces formed by maxilla, premaxilla, palatine, and sometimes jugal. They are expanded posteriorly to form a roughly triangular shape in ventral view in which the lingual ridge converges anteriorly toward the labial ridge. In state 1 the triangle is narrow posteriorly (figs. 9F, H–J, 10B, E). In state 2, the triangle is broader and the midline depression (Character 32) is narrower (fig. 10A, C, D, F, G, I, K). Some Taphrosphyini have relatively wide triturating surfaces (Azabbaremys, Nigeremys), but the lingual and labial ridges are parallel.</p> <p>Primitive condition: Although there is some variation in triturating surface shape in the outgroups, all are narrower and more parallel-sided in comparison to bothremydids.</p> <p>Homoplasy: With a CI of 0.33, this character has homoplasy problems. In the MPC (fig. 301), the derived condition of a wide triturating surface of any sort originates once at Bothremydidae and reverses once at Taphrosphyini. Within the Bothremydini, the very wide condition (state 2) is reversed three times or originates twice and is lost twice. Triangular, or at least very wide, triturating surfaces occur within Podocnemididae and in many cryptodire groups.</p> <p>Discussion: It is possible to subdivide the wide condition into two states, because some Bothremydini have significantly wider palates (Foxemys, Zolhafah, Rosasia, Bothremys, and Chedighaii hutchisoni) than do other bothremydids. Comparing these widths using the width of posterior triturating surface/skull length as a ratio produces two possible ranges: 16–28 for state 1 and 31–40 for state 2. However, within Cearachelys the ratio for two specimens shows a fairly wide range of 21–28, suggesting that the role of individual variation could be considerable. The range of variation in recent broad-jawed taxa (some chelids show a wide range within one species) supports the suggestion that without a larger sample, subtle differences in triturating surface width would best be ignored. We thereforeadopt a fairly simplistic view of what is undoubtedly a more complex character (see also discussion under Araiochelys in the Systematics section for maxilla width in Araiochelys compared with Bothremys maghrebiana). It might also be argued that these states should be ordered, and the MPC is consistent with this, given a few not unreasonable reversals (fig. 301). If ordered, the same MPC results.</p> <p>This character, or a similar version of it, is used by Antunes and Broin (1988), Lapparent de Broin and Werner (1998), and Tong et al. (1998).</p> <p>35. Maxilla, triturating surface pits: absent (Kurmademys) 5 0; present (Bothremys) 5 1.</p> <p>Morphology: The paired conical depressions in the triturating surface are known in Bothremys, Zolhafah, Rosasia, and Araiochelys (figs.123, 128, 133, 137; see also text under Maxilla and Jugal for these taxa). The pit is formed mostly by the maxilla with a widely varying contribution from the jugal.</p> <p>Primitive condition: The absence of triturating pits is primitive, as all pleurodires outside bothremydids lack them.</p> <p>Homoplasy: A shallow pit is present in CNRST-SUNY 199 (fig. 302), an undescribed Taphrosphyini skull. Its morphology, however, is different from the pits in Bothremydini. Some Cearachelys have a shallow pit.</p> <p>Outside pleurodires, a very similar paired set of triturating pits occurs in an undescribed cryptodire from the Paleocene of Morocco, represented by a series of skulls: AMNH 30001, AMNH 30558, and AMNH 30554.</p> <p>Discussion: This character (fig. 302) is a synapomorphy for the subfamily Bothremydini, being absent in Chedighaii. Character 23 (jugal exposed in triturating surface) overlaps with this character in that the formation of the pit exposes the jugal overlying the maxilla in the cheek. This exposure, however, varies widely in extent. The overlap is incomplete in that Cearachelys has some jugal exposure but no deep pit. In any case, deleting this character results in the same MPC.</p> <p>36. Maxilla, accessory ridge on triturating surface: absent (Galianemys) 5 0; present (Euraxemys) 5 1.</p> <p>Morphology: A ridge on the triturating surface between the lingual and labial ridges can be seen in the Euraxemydidae (figs. 42, 47). It also occurs in Sankuchemys (fig. 65). The ridge lies parallel to the lingual and labial ridges.</p> <p>Primitive condition: Proganochelys, basal cryptodires, and most chelids and pelomedusids lack accessory ridges. Within chelids and pelomedusids, accessory ridges do pop up so to speak, but it is unlikely that this is primitive for these groups.</p> <p>Homoplasy: Accessory ridges are frequent within the Podocnemididae (especially Podocnemis), chelids, and pelomedusids, and they are also common within several groups of cryptodires. However, in the MPC accessory ridges are a synapomorphy for the Euraxemydidae. Within the Bothremydidae only Sankuchemys, one Foxemys, and the undescribed CNRST-SUNY 199 have one.</p> <p>Discussion: The triturating surface of turtles has produced accessory ridges on multiple occasions within turtles. However, within the Pelomedusoides, distribution of this character proves useful and it is included in the dataset.</p> <p>37. Maxilla, labial ridge depth below orbit: relatively shallow (roughly equal to or less than orbital diameter) (Galianemys) 5 0; very deep (greater than orbital diameter) (Bothremys) 5 1.</p> <p>Morphology: In Bothremys and Chedighaii hutchisoni the maxilla ventral to the orbit is very deep (figs. 127, 130, 136, 146, 149) compared to Kurmademydini, Cearachelyini, and other Bothremydini.</p> <p>Primitive condition: All outgroups have a relatively shallow labial ridge.</p> <p>Homoplasy: In the MPC, this character has evolved independently within the Bothremydini and the Taphrosphyini. There is morphologic support for this in that the Taphrosphyini maxilla is a very thin sheet of maxilla in contrast to the thick, wedge-shaped maxilla of the Bothremydini.</p> <p>Discussion: Chedighaii barberi is scored as ‘‘?’’ because the orbit is broken along most of the edges in Alabama 2001.2; however, the endocast YPM PU 12951 shows that the orbits were small, as in C. hutchisoni. The labial ridge in C. barberi is shallower than in C. hutchisoni, but it is still deep compared to other Bothremydini.</p> <p>38. Maxilla, maxilla-quadratojugal contact: absent (quadratojugal present) (Euraxemys) 5 0; present (Galianemys) 5 1; absent (quadratojugal absent, chelids only) (Emydura) 5 2.</p> <p>Morphology: The lateral face of the turtle skull is made up by the maxilla anteriorly, the jugal and postorbital posterior to the orbit, and the quadratojugal, quadrate, and squamosal posteriorly. In most turtles the jugal is positioned posteroventrally to the orbit and reaches the cheek margin (Gaffney, 1990: fig. 16). In this position it prevents maxilla-quadratojugal contact. If the jugal is retracted from the cheek margin, the quadratojugal may meet the maxilla ventral to the jugal. This is the condition seen in the tribes Kurmademydini, Cearachelyini, and Bothremydini (figs. 3, 4). In the Taphrosphyini the quadratojugal is small and dorsal (fig. 5).</p> <p>Primitive condition: Separation of the maxilla and quadratojugal by the jugal occurs in all the relevant outgroups (fig. 3).</p> <p>Homoplasy: Maxilla-quadratojugal contact occurs in some cryptodires independently. Within the Bothremydidae the absence of a maxilla-quadratojugal contact is a Taphrosphyini synapomorphy. In this tribe the quadratojugal is retracted dorsally and lacks the ventral portion (see character 13), typically present in other Pelomedusoides. Therefore, there is morphological support for the nonhomology of the primitive condition in Taphrosphyini versus the pleurodiran outgroups outside Bothremydidae.</p> <p>Discussion: Although the character is not determinable in a number of bothremydids, its distribution in the MPC shows it as a synapomorphy for Bothremydidae and its reversal as a synapomorphy for Taphrosphyini.</p> <p>39. Maxilla, maxilla-quadrate contact, cheek emargination: absent, little or no emargination (Galianemys) 5 0; present, no emargination (Azabbaremys) 5 1; absent, barely separated by narrow fissure (Phosphatochelys) 5 2; absent, deep emargination, quadratojugal present (Euraxemys) 5 3; absent, deep emargination, quadratojugal absent (Emydura) 5 4.</p> <p>Morphology: The lateral surface of the turtle skull is made up of the maxilla anteriorly, the jugal and postorbital posterior to the orbit, and the quadratojugal, quadrate, and squamosal posteriorly (Gaffney, 1979a). In most turtles both the jugal and the quadratojugal reach the cheek margin (Gaffney, 1990: fig. 16). In this position they prevent maxilla-quadrate contact. If both the jugal and quadratojugal are placed dorsally from the cheek margin, then the maxilla may contact the quadrate, and this is state 1 (fig. 4D, H). Within the Bothremydidae, an anteriorly elongate quadrate and an elongate maxilla meet to prevent jugal and quadratojugal exposure on the cheek margin. This contact is present in most Taphrosphyini, but there is some variation in form. In Azabbaremys (figs. 5J, 215) the contact results from a broad, posterior process of the maxilla. In Labrostochelys and Taphrosphys there is a narrow quadrate-maxilla contact, with an anterior process of the quadrate not seen in Azabbaremys or Phosphatochelys. Within the Bothremydini, Rosasia, Araiochelys, and Bothremys have a broad quadrate-maxilla contact.</p> <p>State 2 (fig. 5D) is the narrow fissure present in Phosphatochelys and Ummulisani, which separates the quadrate and maxilla. This does not seem to be homologous with the deep emargination condition with the quadratojugal present, state 3 (fig. 3D). State 4 (fig. 3A) is the condition of a deep emargination with the quadratojugal entirely missing, known only in chelids.</p> <p>Primitive condition: Intervention of the jugal and quadratojugal between the maxilla and quadrate occurs in all outgroups.</p> <p>Homoplasy: We are unaware of any turtles outside of the Bothremydidae in which contact between the maxilla and quadrate occurs. The MPC shows the quadrate-maxilla contact occurring within the Taphrosphyini and within the Bothremydini (fig. 296A). Foxemys and Polysternon lack the contact and have the primitive condition for the quadratojugal, so it can be interpreted that the presence of the quadrate-maxilla contact is not primitive for Bothremydini. However, a large quadratojugal is present in Chedighaii hutchisoni, although not well preserved (and not determinable in C. barberi), so presence of a maxilla-quadrate contact in the other Bothremydini is equivocal. The MPC is still consistent with a single origin of a maxilla-quadrate contact for the Bothremydodda (Taphrosphyini + Bothremydini) with reversals in the Foxemydina and Nigeremydina (see below).</p> <p>Discussion: Character state 1 may not be homologous between the Taphrosphyini and the Bothremydini, due to different morphologies as well as ambiguity in the MPC (fig. 296A). Alternatively, it may be a synapomorphy for the tribes Bothremydini + Taphrosphyini and may be reversed in Foxemys, Polysternon, and Chedighaii. Character state 3 is a synapomorphy for Pelomedusoides and is lost in the subfamily Bothremydinae (tribes Cearchelyini + Bothremydini + Taphrosphyini).</p> <p>This character or a version of it is used in Antunes and Broin (1988).</p> <p>40. Maxilla, orbitonarial bar width: roughly equal to or slightly less than diameter of orbit (Galianemys) 5 0; wider than orbit (Bothremys) 5 1; more than twice orbital diameter (Labrostochelys) 5 2; very narrow, much less than diameter of orbit (Phosphatochelys) 5 3.</p> <p>Morphology: The bone between the orbit and the lateral margin of the apertura narium externa, the orbitonarial bar, is formed by the maxilla and prefrontal, but usually the maxilla forms most of it. The width of this bar varies, and this character is an attempt to use the extremes of this variation. The extremely narrow orbitonarial bar (state 3, fig. 5D) present in Phosphatochelys, Ummulisani, and Rhothonemys is unique in pleurodires. The Bothremydini have a wider bar than in most pleurodires, and Bothremys is the widest (state 1, fig. 4H). The Bothremys arabicus condition is unknown, however. Labrostochelys is unique among pleurodires in its extremely long snout and very wide orbitonarial bar (state 2, fig. 5G).</p> <p>Primitive condition: The intermediate state (state 0) is fairly consistent among the outgroups, Proganochelys, chelids, and pelomedusids, but it is unlikely that all the intermediate states identified here are actually homologous.</p> <p>Homoplasy: As restricted here, the states are not homoplastic in the MPC, but variation of the orbitonarial width is considerable throughout turtles.</p> <p>Discussion: Although this character is not defined with precision, it seems to be the best way to obtain information from this morphology. Measuring some parameters might enhance the use of the character and allow more states to be distinguished, but there is a great deal of variation of this character in turtles and a very restricted usage seems best. Nonetheless, this is a relatively subjective character set and must be used with caution.</p> <p>41. Maxilla, dorsal process onto skull roof: maxilla more lateral and ventral (Galianemys) 5 0; maxilla extending dorsomedially onto skull roof, restricting lateral extent of prefrontal (Bothremys cooki) 5 1.</p> <p>Morphology: The dorsal process of the maxilla extends onto the skull roof in two Bothremys species, B. maghrebiana and B. cooki, restricting the prefrontal exposure in dorsal view (fig. 7G, H). The maxilla is more extensive medially in B. cooki than in B. maghrebiana, and in both species the prefrontal is more L-shaped in contrast to the more rectangular prefrontal of other pleurodires.</p> <p>Primitive condition: Rectangular prefrontals and no dorsal extension of the maxilla are found throughout all outgroups.</p> <p>Homoplasy: None apparent.</p> <p>Discussion: Presumably the wide orbitonarial bar and very short snout in Bothremys are related to the dorsal extent of the maxilla.</p> <p>42. Maxilla, ventral rim of orbit: rim with distinct margin (Galianemys) 5 0; rim absent, continuous slope (Bothremys) 5 1.</p> <p>Morphology: In most turtles, the floor of the fossa orbitalis is nearly horizontal and the lateral surface of the maxilla is nearly vertical, with the two surfaces meeting at a distinct edge, often forming a ridge. In Bothremys cooki and B. maghrebiana the two surfaces are continuous without a distinct edge or break in slope, state 1 (figs. 129, 138).</p> <p>Primitive condition: The outgroups, Proganochelys, chelids, pelomedusids, euraxemydids, and Cearachelyini, all have a low ridge marking the change in slope between the fossa orbitalis floor and the external surface of the maxilla.</p> <p>Homoplasy: The absent rim of Bothremys cooki and B. maghrebiana is closely approached by Foxemys, which is coded as having this character. However, Foxemys does have more of a rim than does Bothremys, although the distinction is somewhat subjective. One specimen of B. maghrebiana, MHNL 20-268370, has a low rim (see discussion under Systematics, B. maghrebiana), showing that there is some intraspecific variation of this character.</p> <p>Discussion: Although it would seem likely that this character should be related to size of the fossa orbitalis, all Bothremys have a large fossa and only two of the species lack the rim.</p> <p>43. Maxilla, exposure in orbital floor: maxilla broadly exposed (Galianemys) 5 0; maxilla narrowly or not exposed (Azabbaremys) 5 1.</p> <p>Morphology: In most turtles the maxilla forms the major part of the floor of the fossa orbitalis. In Taphrosphys ippolitoi, Labrostochelys, CNRST-SUNY 199, and Azabbaremys the maxilla does not have an extensive medial process as in other turtles (fig. 280). The orbital floor in these forms is formed mostly by the palatine.</p> <p>Primitive condition: The wide occurrence of a medial maxillary process in the outgroups shows it to be primitive for pleurodires.</p> <p>Homoplasy: The character must be lost in Phosphatochelys, Arenila, and Ummulisani.</p> <p>Discussion: As the character is only determinable in one of three Taphrosphys species, a new discovery could alter this distribution; as it is, this character is a subtribe Taphrosphyina synapomorphy.</p> <p>44. Vomer, maxilla-vomer contact: present (Proganochelys) 5 0; absent (Azabbaremys) 5 1.</p> <p>Morphology: The vomer is restricted to the premaxilla and allows premaxilla exposure on the apertura narium interna (fig. 215B). The premaxilla may be exposed on the apertura narium interna if there is no vomer-maxilla contact (figs. 65, 155) or if the vomer is simply absent (fig. 21). The character could be coded with a third state for this latter condition. This also has the effect of counting the vomer absent condition (character 45) twice. We have combined both conditions as one state.</p> <p>Primitive condition: A vomer with a narrow anterolateral maxillary contact is present in Proganochelys, early cryptodires, and chelids, and it is presumed to be primitive for pleurodires. The absence of a contact would then be the derived state.</p> <p>Homoplasy: This is a highly variable character with a CI of 0.16. Keeping this character demonstrates the complete objectivity of this work, and any decent amount of cooking would remove it. The loss and subsequent reappearance of the vomer is suspected within the Podocnemididae.</p> <p>Discussion: The Kurmademydini and podocnemidids have this character, so it may be primitive at the level of the superfamily Podocnemidoidea within Pelomedusoides, although with multiple reversals. It also unites Azabbaremys and CNRST-SUNY 199. Due to the fragile nature of the vomer area, there are many missing data for taxa that otherwise have well-preserved skulls. Better material may eventually clarify the distribution of this character.</p> <p>45. Vomer: present, paired (Proganochelys) 5 0; present, single (Galianemys) 5 1; absent (Pelusios) 5 2.</p> <p>Morphology: The living Pelomedusoides are unusual among living turtles for lacking a vomer (its apparent presence in some living podocnemidids is interpreted here as a neomorph). However, the fossil record shows that the vomer was widely present in extinct Pelomedusoides. Pelusios and Pelomedusa lack a vomer but the condition in Araripemys is indeterminate, although it probably lacked a large, ‘‘normal’’ vomer. Hamadachelys, based on two specimens, has a vomer, and some extinct podocnemidids have well-developed vomers. Where determinable, all bothremydids have vomers.</p> <p>Primitive condition: A vomer is primitive for pleurodires.</p> <p>Homoplasy: Within Podocnemididae the vomer may be lost twice. It is lost independently in Pelomedusidae.</p> <p>Discussion: In the MPC, the vomer loss does not define any groups, other than Pelomedusidae. It is very easy for the small, loosely attached vomer to be missing in fossil skulls and to fall out of recent ones. Nonetheless, representation within the Bothremydidae is good, and there is no indication of loss within the group.</p> <p>This character is used in Gaffney et al. (1991), Lapparent de Broin and Werner (1998), Meylan (1996), and Rougier et al. (1995).</p> <p>46. Vomer, vomerine teeth: present (Proganochelys) 5 0; absent (Pelusios) 5 1.</p> <p>See Gaffney (1990), Gaffney et al. (1991), Gaffney and Kitching (1995), and Rougier et al. (1995).</p> <p>47. Vomer, central bar: thin, sutured at both ends (Proganochelys) 5 0; thin, attached anteriorly only (Azabbaremys) 5 1; vomer absent (Emydura) 5 2.</p> <p>Morphology: In Azabbaremys and CNRST-SUNY 199 the vomer tapers posteriorly and ends before reaching the palatine attachment (fig. 216).</p> <p>Primitive condition: A narrow vomer, attached at both ends, occurs in the outgroups (fig. 9).</p> <p>Homoplasy: None known.</p> <p>Discussion: When first seen in Azabbaremys, the senior author thought this was due to preservational damage, but there is no indication of that, and CNRST-SUNY 199 has a very similar morphology with a clearly well-preserved vomer that is sutured anteriorly only.</p> <p>48. Palatine, foramen palatinum posterius: in floor of orbit (Chelydra) 5 0; behind orbit, in floor of sulcus palatinopterygoideus (Pelusios) 5 1.</p> <p>Morphology: The foramen palatinum posterius is described and figured in Gaffney (1979a: figs. 53–65) for a number of turtles. In cryptodires, the foramen lies in the floor of the fossa orbitalis, but in pleurodires it is separated from the fossa due to the presence of the septum orbitotemporale and the sulcus palatinopterygoideus (figs. 23. 24). The foramen is usually in the floor of the sulcus palatinopterygoideus.</p> <p>Primitive condition: Proganochelys and cryptodires lack this character.</p> <p>Homoplasy: None known.</p> <p>Discussion: This character is synapomorphic at least for Eupleurodira, being unknown for shell-only taxa. A decently preserved skull is necessary for determining the character. The orbit or sulcus palatinopterygoideus needs to be visible; a ventral view of the foramen palatinum posterius is insufficient.</p> <p>This character is used by Gaffney and Meylan (1988), Gaffney et al. (1991), and Fuente and Iturralde-Vinent (2001).</p> <p>49. Palatine, dorsally arched palate: absent (Galianemys) 5 0; present (Azabbaremys) 5 1.</p> <p>Morphology: The area between the lingual ridges of the triturating surfaces forms the roof of the mouth and the choanal passages. In Azabbaremys, CNRST-SUNY 199, Nigeremys, Phosphatochelys, and probably Rhothonemys, this area, particularly the part formed by the palatines posterior to the apertura narium interna, is an anterodorsally sloping surface that rises well above the level of the maxillary triturating surfaces (fig. 215C). The anterolateral margins of the apertura narium interna are relatively low, so the result is an apertura that is deeper than in other bothremydids.</p> <p>Primitive condition: Although the outgroups and other pleurodires have many different shapes to the central palatal surface, all are shallower than in these taxa. A relatively flat palate is found in most relevant outgroups.</p> <p>Homoplasy: There is a reversal in Labrostochelys; otherwise, all Taphrosphyini that can be determined (only 5 out of 11) have the character present.</p> <p>Discussion: Arenila is scored as ‘‘?’’ because the area is damaged, but the MPC suggests that it should have the deep choanal passage/ arched palate, based on the morphology that is present. The best skull of Taphrosphys, the type of T. ippolitoi, is damaged in this region, but the palatines as preserved have an anterodorsal slope, suggesting that it also has an arched palate. If this proves to be the case, this character will be a Taphrosphyini synapomorphy with one reversal.</p> <p>50. Palatine, palatine contribution to triturating surface: little or none (Euraxemys) 5 0; moderate to extensive (Bothremys) 5 1.</p> <p>Morphology: The upper triturating surface of turtles is usually made up mostly by the maxilla with a smaller contribution by the premaxilla anteromedially. The palatine is typically present just medial to the triturating surface and may also provide a small contribution. In many bothremydids, the palatine forms a significant part of the posteromedial part of the triturating surface (figs. 9F, 10H), and the maxilla-palatine suture is more anterolateral than in the primitive condition.</p> <p>Primitive condition: The outgroups have little or no palatine contribution to the triturating surface.</p> <p>Homoplasy: The character is a Bothremydidae synapomorphy, lost in the Taphrosphyini. The occurrence in Araripemys is probably independent on morphological grounds, as the triturating surface is narrow. The character is unclear in Sankuchemys; it may be present but the specimen is ambiguous and has been coded ‘‘?’’.</p> <p>Discussion: Although there is a gradational aspect to this character, we have tried to restrict it to the most extreme condition, particularly as seen in the Bothremydini. Nonetheless, some decisions about scoring are subjective. This character is generally correlated with the wide triturating surface in many bothremydids, but it is not a consistent correlation (Araiochelys and Araripemys are exceptions).</p> <p>This character is used in Meylan (1996) and Tong et al. (1998).</p> <p>51. Quadrate, antrum postoticum: absent, open incisura columellae auris (Proganochelys) 5 0; small (Bothremys) 5 1; absent, closed incisura columellae auris (Azabbaremys) 5 2; moderate to large (Galianemys) 5 3.</p> <p>Morphology: The antrum postoticum shows a wide range of variation in Pelomedusoides (figs. 176, 281–286). The antrum postoticum is smaller in many bothremydids than it is in other pleurodires. In Azabbaremys, Nigeremys, Ummulisani, and Arenila, it is completely filled with bone and no indication of the antrum is present in the cavum tympani (state 2, fig. 281C). This condition is clearly identifiable. The remaining taxa have a varying size for the antrum postoticum, and we have identified the small extreme (state 1, fig. 286D) and the moderate to large (state 3, fig. 281A, 282, 284) as character states. It is useful to compare figure 284C with figure 286D; both are broken, exposing the internal shape of the antrum postoticum.</p> <p>The small condition, state 1, is found in Labrostochelys, Araiochelys, Bothremys maghrebiana, and Chedighaii barberi (it is indeterminate for the other species of Bothremys and Chedighaii). However, within state 3 (moderate to large), Taphrosphys (fig. 176), for example, has an antrum that is larger than that in Labrostochelys but smaller than those in the Kurmademydini and Cearachelyini (figs. 283, 284). We have been unable to distinguish this degree of gradation because it seems to be too subjective.</p> <p>Primitive condition: Proganochelys lacks an antrum postoticum, but a large antrum is apparently primitive for pleurodires as it occurs in chelids, pelomedusids (fig. 282A), and Araripemys (fig. 282C). However, euraxemydids and podocnemidids have a smaller antrum, as do the Kurmademydini and Cearachelyini. All these are coded within the ‘‘moderate to large’’ character state 3.</p> <p>Homoplasy: Although the CI is a respectable 0.5, there is actually more homoplasy within bothremydids, which is hidden by the lumping of a lot of size variation into the ‘‘moderate to large’’ character state 3. It is difficult to divide this continuous variation objectively (except for absence) and is therefore hard to identify independent acquisitions morphologically. As defined here, the small condition (state 1) is acquired twice, once for Araiochelys + Bothremys + Chedighaii within the Bothremydini and once in the Taphrosphyini in Labrostochelys. The absent condition, state 2, appears independently three times, in Ummulisani, Azabbaremys, and Nigeremys.</p> <p>Discussion: Although the size of the antrum postoticum varies widely in pleurodires, from very large to completely absent, it has been difficult to objectively divide this variation into discrete character states. The difference between ‘‘moderate’’ and ‘‘small’’ is subjective and based on what we perceive as a gap in antrum size. More specimens may alter this division. Attempts to measure the variation have been unsatisfactory but could be worth future efforts.</p> <p>This character is used in Gaffney and Meylan (1988), Meylan (1996), and Tong et al. (1998).</p> <p>52. Quadrate, incisura columellae auris: no posterior bony restrictions (Euraxemys) 5 0; eustachian tube and stapes separated by bone or a narrow fissure (Foxemys) 5 1; eustachian tube and stapes enclosed together by bone (Podocnemis) 5 2.</p> <p>Morphology: The incisura columellae auris can be open to a varying degree (state 0, fig. f281A) or it can be closed by a meeting or near meeting of dorsal and ventral processes of the quadrate. In state 1, the incisura is closed, or nearly closed, separating the stapes and eustachian tube (fig. f281B, C). In state 2, the dorsal and ventral processes meet or nearly meet, posterior to the eustachian tube, enclosing both stapes and eustachian tube in the same oval opening (Gaffney, 1979a: figs. 134, 140).</p> <p>Primitive condition: The open incisura columellae auris of euraxemydids, early cryptodires, and Proganochelys is the presumed primitive condition for pleurodires. However, the apparently independent occurrence of state 2 in chelids and pelomedusids, as well as podocnemidids in the MPC (fig. 303), suggests an alternative that the enclosure of stapes and eustachian tube may be primitive for eupleurodires and lost in euraxemydids, Brasilemys, Araripemys, and Teneremys.</p> <p>Homoplasy: None for state 1, but state 2 occurs three times independently (see above) in the MPC (fig. 303).</p> <p>Discussion: The main objection to this character is that state 1 might be interpreted as redundant with character 53, incisura columellae auris completely closed to form a canal containing the stapes. The decision to make two characters using different morphologic criteria in this area is based on the open, but slitlike condition of the incisura in a few bothremydids, Cearachelys (fig. 283), Foxemys (fig. 281B), and Polysternon. Therefore, the two characters are not strictly redundant, and we use state 1 to try to reflect another aspect of the cavum tympani morphology.</p> <p>The position of the eustachian tube in a fossil turtle is not, strictly speaking, determinable. The position of this soft tissue structure may not be indicated in bone. However, examination of thin sections and dissections of recent turtles by the senior author shows that its position and structure are relatively consistent in all turtles, particularly pleurodires. Although the eustachian tube in recent pleurodires does tend to take the shape of surrounding bones, it is unlikely that it would be thin and narrow enough to fit into the fissure or slitlike incisura columellae auris found in Cearachelys, Foxemys, and Polysternon. Its position in forms like the Euraxemydidae, with a wide incisura, is not determinable, but a distinct groove (the sulcus eustachii) showing its position is present on the posterior surface of the quadrate in bothremydids. Therefore, it is possible to argue that in bothremydids, the stapes and eustachian tube were separated by bone, either completely by bone or with a narrow fissure in the bone remaining, in contrast to all other pleurodires.</p> <p>Although Araripemys is open posteriorly and we have coded it as ‘‘0’’, there is a small dorsal and ventral process (fig. 282) that almost completely closes the incisura. In euraxemydids the incisura is more open than in Araripemys: however, there is a partial restriction with small dorsal and ventral processes. Thus, euraxemydids (also coded as ‘‘0’’) could be coded separately from Araripemys as a different state, or Araripemys could be coded as ‘‘2’’. Using this approach, however, does not change the MPC.</p> <p>A version of this character is used in Antunes and Broin (1988), Meylan (1996), Lapparent de Broin and Werner (1998), and Tong et al. (1998).</p> <p>53. Quadrate, stapes contained in bony canal: stapes not completely contained in bone (Euraxemys) 5 0; stapes completely enclosed by bony incisura columellae auris (Bothremys) 5 1.</p> <p>Morphology: The quadrate of most bothremydids completely surrounds the stapes, causing the incisura columellae auris to be a bony canal. This character is easily determined; that is, there are no cases of ambiguity. As can be seen in figures 176, 281, and 286, the canal is encased by bone on all sides, even in the Kurmademydini (fig. 282B) and Galianemys (fig. 284), which are more generalized in most characters than in other bothremydids. The narrow fissure condition seen in Foxemys (fig. 281B), Polysternon, and Cearachelys (fig. 283) is exclud- ed from this character.</p> <p>Primitive condition: An open quadrate, with the incisura columellae auris only partially surrounding the stapes and not forming a canal, is found in all the relevant outgroups (fig. 282).</p> <p>Homoplasy: Two reversals of this character occur in Cearachelys and the Foxemydina (fig. 304). The reversal is a synapomorphy for Foxemys + Polysternon. The morphology of the open incisura columellae auris in these bothremydids does differ from the open condition in outgroups like podocnemidids, pelomedusids, euraxemydids, and chelids (see character 52 for discussion). Lapparent de Broin (2000b) considered the Polysternon- Foxemys condition a reversal as well. A number of cryptodires have a completely closed incisura columellae auris (Gaffney, 1979a, 1996), but they do not develop the bony canal as seen in bothremydids.</p> <p>Discussion: The bony canal for the stapes in bothremydids is an unusual feature, synapomorphic at the level of Bothremydidae (fig. 304), and it is not found in any other pleurodires.</p> <p>This character is used in Gaffney and Meylan (1988), Lapparent de Broin and Werner (1998), Tong et al. (1998), and Lapparent de Broin (2000b).</p> <p>54. Quadrate, sulcus eustachii: without ventral process (Bothremys) 5 0; with ventral process overhanging dorsal margin (Labrostochelys) 5 1.</p> <p>Morphology: The groove on the posterior surface of the quadrate, presumably marking the position of the eustachian tube (the sulcus eustachii), forms an indentation on the posterior margin of the cavum tympani. In Taphrosphys, Labrostochelys, and Phosphatochelys, the anterodorsal margin of the notch has a small, ventrally dependent process. In Labrostochelys (fig. 287) the process is narrow, but in Phosphatochelys (fig. 199) and Taphrosphys it is wider, forming a small, anteroposteriorly broad flange.</p> <p>Primitive condition: All outgroups and other pleurodire taxa lack this process.</p> <p>Homoplasy: None known. We know of no other turtle with this process.</p> <p>Discussion: The small ventral process at the posterior edge of the cavum tympani, above the sulcus eustachii, seems to be related to some soft structure, probably the attachment of the eustachian tube, which enters the cavum tympani at this edge. The process is broken off in the Taphrosphys specimens, but its presence is determinable from the broken base.</p> <p>55. Quadrate, trough on incisura columellae auris ridge: absent (Bothremys) 5 0; present (Galianemys) 5 1.</p> <p>Morphology: When the incisura columellae auris is completely closed by bone, as in most bothremydids, there may be a ridge in the position across the surface of the cavum tympani, extending from the remnant of the incisura (the bony stapedial canal) to the sulcus eustachii. In Kurmademys (fig. 282B) and Galianemys (fig. 284) this ridge has a shallow groove along its lateral surface. This is thought to be a suture in Lapparent de Broin (2000b), but it is only a surface feature.</p> <p>Primitive condition: A closed incisura columellae auris is absent in all the pleurodire outgroups, so none has a ridge or a trough. In the other bothremydids, there may be a low, poorly defined trough (Labrostochelys) but no distinct ridge.</p> <p>Homoplasy: In the MPC, the character evolves once in Kurmademys and independently in Galianemys. However, the incisura is open in Cearachelys, and the character may be primitive for Bothremydidae and lost in Cearachelys and in the infrafamily Bothremydodda (the tribes Bothremydini + Taphrosphyini).</p> <p>Discussion: This character is a distinctive one for Galianemys. Although similar to the condition in Kurmademys, Galianemys has the distal ends of the groove separating, making it different from Kurmademys.</p> <p>56. Quadrate, fossa precolumellaris: very small to absent (Galianemys) 5 0; present but shallow (Euraxemys) 5 1; deep and well defined (Pelusios) 5 2.</p> <p>Morphology: Just anterior to the incisura columellae auris, where the quadrate forms the medial wall of the cavum tympani, many pleurodires have a depression, the fossa precolumellaris. Described and figured by Williams (1954b) in Podocnemididae (also in Gaffney, 1979a) as the precolumellar fossa, we have formalized it as the fossa precolumellaris. The distinction between shallow (state 1, fig. 281A) and deep (state 2, fig. 282A, B) is not as arbitrary as it might seem. The euraxemydid condition (state 1) shows a small dimple, which we think should be differentiated from the deep condition (state 2) seen in pelomedusids, chelids, Araripemys, and Hamadachelys.</p> <p>Within Podocnemididae, the fossa varies in size, as described by Williams (1954b). All bothremydids except Kurmademys (it is indeterminate for Sankuchemys) lack a fossa precolumellaris, so that the cavum tympani anterior to the incisura columellae auris is smooth (fig. 281B, C).</p> <p>Primitive condition: The fossa precolumellaris is absent in Proganochelys and cryptodires, but a deep one is present in chelids and pelomedusids, the presumed primitive condition for pleurodires (a variable one is present in podocnemidids).</p> <p>Homoplasy: Most bothremydids lack a fossa precolumellaris, and this is the primitive condition for turtles; however, this is a reversal and must have originated independently within bothremydids, as pleurodiran outgroups have a deep fossa.</p> <p>Discussion: Kurmademys has a deep fossa precolumellaris, as in pleurodire outgroups Pelomedusidae and Chelidae. All other bothremydids lack the fossa, which is a synapomorphy for the subfamily Bothremydinae (the tribes Taphrosphyini + Bothremydini + Cearachelyini).</p> <p>This character, or one like it, is used by Meylan (1996), Lapparent de Broin and Werner (1998), Tong et al. (1998), and Lapparent de Broin (2000b).</p> <p>57. Quadrate, shelf below cavum tympani: absent (Galianemys) 5 0; present, lower portion of cavum tympani unusually deep (Bothremys) 5 1.</p> <p>Morphology: In the bothremydid tribes Bothremydini and Taphrosphyini the cavum tympani is recessed deeply into the quadrate, and its lower edge is deep, forming a sloping shelf along the ventral margin of the cavum (figs. 285, 286). In Labrostochelys and Phosphatochelys the cavum is not recessed, but the shelf persists as a ventrally sloping surface.</p> <p>Primitive condition: All outgroups lack a ventral shelf on the quadrate.</p> <p>Homoplasy: None known.</p> <p>Discussion: The principal problem with this character is variation in the slope of the shelf within the tribe Taphrosphyini; howev- er, scoring Labrostochelys and Phosphatochelys as absent produces the same MPC.</p> <p>58. Quadrate, medial process contacting braincase elements and underlying cranioquadrate space: absent (Chelydra) 5 0; present (Pelusios) 5 1.</p> <p>Morphology: This character is figured and described in Gaffney (1975 b, 1979a). The quadrate of pleurodires has a medial process that contacts the prootic and basisphenoid, although on the ventrally exposed surface, these contacts are not always exposed. The basisphenoid itself may cover the prootic or the prootic may contact the pterygoid. The medial process underlies the cranioquadrate space, which in the adult is the canalis cavernosus.</p> <p>Primitive condition: The character is absent in Proganochelys and Cryptodira.</p> <p>Homoplasy: None known.</p> <p>Discussion: This character is a synapomorphy for Pleurodira. This character is used in Gaffney and Meylan (1988), Gaffney et al. (1991), and Fuente and Iturralde-Vinent (2001).</p> <p>59. Quadrate, quadrate-basioccipital contact: absent (Euraxemys) 5 0; present (Galianemys) 5 1.</p> <p>Morphology: The medial process of the quadrate in the Podocnemididae and Bothremydidae is larger and more extensive posteromedially than in other pleurodires (fig. 9H–J). The shape of the basioccipital is not very different in pleurodires with respect to this character; it is primarily a difference in quadrate shape that causes the contact. The quadrate covers the processus interfenestralis of the opisthotic and the prootic ventrally, resulting in a significant difference in the basicranium between podocnemidoids (podocnemidids + bothremydids) and all other pleurodires.</p> <p>Primitive condition: Proganochelys and cryptodires completely lack the medial process of the quadrate (Gaffney, 1975 b, 1979a). Within pleurodires, a smaller medial quadrate process is present in chelids, pelomedusids, and Araripemys; as they lack a basioccipital-quadrate contact, the prootic is exposed. This appears to be the primitive condition for pleurodires.</p> <p>Homoplasy: None known.</p> <p>Discussion: This character supports the monophyly of the families Podocnemididae + Bothremydidae as the superfamily Podocnemidoidea and represents a major difference between their basicrania and those in all other pleurodires.</p> <p>This character is in Antunes and Broin (1988), Meylan (1996), Lapparent de Broin and Werner (1998), and Tong et al. (1998).</p> <p>60. Quadrate, condylus mandibularis position: near or in line with the basioccipital-basisphenoid suture (Galianemys) 5 0; distinctly anterior to plane of basioccipital-basisphenoid suture (Pelusios) 5 1; distinctly posterior to condylus occipitalis (Nigeremys) 5 2.</p> <p>Morphology: This character is an attempt to use the variation in position of the condylus mandibularis relative to the elements of the basicranium. Although this variation is somewhat continuous, it is apparent that most bothremydids, compared to other pleurodires, have the condylus mandibularis far posterior, relative to the condylus occipitalis. This may also be described as a shortened or telescoped basicranial and otic region (Lapparent de Broin and Werner, 1998). The character has been determined by drawing a line between each condylus mandibularis and seeing where the basioccipital-basisphenoid suture falls with respect to this line. If the line falls slightly behind, on, or slightly anterior to the suture, it is character state ‘‘0’’ (fig. 9H). If the line is well anterior to the basioccipital-basisphenoid suture, that is, well onto or anterior to the basisphenoid, it is character state ‘‘1’’ (fig. 9B). In Nigeremys and Arenila the line across the condylus mandibularis falls so far behind the basioccipital-basisphenoid suture that it is posterior to the condylus occipitalis, and this is character state ‘‘2’’ (fig. 11H, I).</p> <p>Primitive condition: Proganochelys and early cryptodires have state ‘‘0’’, the primitive state at the level of all turtles. However, as all the pleurodire outgroups have state ‘‘1’’, this seems to be primitive for pleurodires.</p> <p>Homoplasy: This character has a CI of 0.33, showing that there is a lot of homoplasy. Bothremydids are characterized by a reversal to state ‘‘0’’ at the level of the subfamily Bothremydinae (consisting of the tribes Cearachelyini, Bothremydini, and Taphrosphyini). Within this group a number of the Taphrosphyini have a reversal to state ‘‘1’’ independently of Polysternon, which is also coded ‘‘1’’. However, this character is a relatively simplified summary of a lot of complex morphology, making more detailed comparisons to test homoplasy inconclusive.</p> <p>Discussion: The difficulty with this character is scoring intermediate taxa (e.g., Azabbaremys and Labrostochelys) that have a condylus mandibularis just anterior to the basioccipital-basisphenoid suture. We have scored both as ‘‘0’’ because the condylus mandibularis line falls close to the suture, although they could be scored ‘‘1’’ because the line is just anterior to the suture. We have run the dataset both ways with the same MPC resulting.</p> <p>A similar character is used in Lapparent de Broin and Werner (1998).</p> <p>61. Quadrate, fully formed cavum tympani: no (Proganochelys) 5 0; yes (Pelusios) 5 1.</p> <p>See Gaffney (1990), Gaffney and Kitching (1995), and Rougier et al. (1995).</p> <p>62. Quadrate, cavum tympani with acute posterior edge: no (Proganochelys) 5 0; acute edge, also enclosing stapes (Pelusios) 5 1.</p> <p>See Gaffney (1990), Gaffney and Kitching (1995), and Rougier et al. (1995).</p> <p>63. Quadrate, middle ear with complete lateral wall: no (Proganochelys) 5 0; yes (Pelusios) 5 1.</p> <p>See Gaffney (1990), Gaffney et al. (1991), Gaffney and Kitching (1995), and Rougier et al. (1995).</p> <p>64. Quadrate, cavum tympani curved dorsally: no (Proganochelys) 5 0; yes (Palaeochersis) 5 1.</p> <p>See Gaffney (1990), Gaffney and Kitching (1995), and Rougier et al. (1995).</p> <p>65. Quadrate, covers opisthotic laterally: no (Proganochelys) 5 0; yes (Australochelys) 5 1.</p> <p>See Gaffney (1990), Gaffney et al. (1991), Gaffney and Kitching (1995), and Rougier et al. (1995).</p> <p>66. Quadrate, pocket for stapes articulation: present (Proganochelys) 5 0; absent (Australochelys) 5 1.</p> <p>See Gaffney (1990), Gaffney and Kitching (1995), and Rougier et al. (1995).</p> <p>67. Quadrate, cranioquadrate space: relatively open (Proganochelys) 5 0; well-defined canal (Australochelys) 5 1.</p> <p>See Gaffney (1990), Gaffney and Kitching (1995), and Rougier et al. (1995).</p> <p>68. Pterygoid, fossa pterygoidea: absent or small (Pelusios) 5 0; moderate (Galianemys whitei) 5 1; deep and narrow (Foxemys) 5 2.</p> <p>Morphology: The fossa pterygoidea in bothremydids is an anteromedial–posterolaterally elongate depression formed by the pterygoid, quadrate, and basisphenoid (figs. 101, 102). The foramen posterius canalis carotici interni, the foramen nervi facialis, and the foramen nervi vidiani may open within this depression. The prootic may be exposed in the deepest part of the depression in some forms (Kurmademys, fig. 276E; Galianemys emringeri, fig. 277E).</p> <p>The distinction between the two states of fossa development is not arbitrary because there is a gap in the size variation. Kurmademys (fig. 55), Cearachelys (two of three specimens) (fig. 74), Galianemys emringeri (fig. 82), and Rosasia (fig. 119) have a fossa pterygoidea that is not as deep as it is wide. The margin is recessed and the center is relatively shallow (state 1). In Foxemys (fig. 102), Polysternon (fig. 109), Nigeremys, and Arenila (fig. 225), the fossa pterygoidea is about as deep as it is wide, particularly at its center (state 2).</p> <p>Lapparent de Broin and Werner (1998) and Lapparent de Broin (2000b) treated this structure as homologous to what we call the cavum pterygoidei (here restricted to the epifamily Podocnemidinura, which is the</p> <p>Podocnemididae + Hamadachelys + Brasilemys) and referred to this depression as the ‘‘podocnemidid fossa’’. They asserted that it becomes enlarged to form ‘‘the true enlarged carotid canal of the Podocnemididae’’ (Lapparent de Broin, 2000b: 69). However, unlike the cavum pterygoidei of podocnemidids, there is no bony covering beneath the fossa pterygoidea and it never ends anteriorly in a single large opening, both features of the cavum pterygoidei. Thus, we treat the fossa pterygoidea as an independent structure from the cavum pterygoidei. Furthermore, the cladogram shows no homologous relationship between these concavities; they are both derived independently.</p> <p>Primitive condition: Depressions of this kind are absent in the pterygoids of chelids, pelomedusids, Araripemys and euraxemydids. The absence of a fossa pterygoidea is the primitive condition.</p> <p>Homoplasy: Lapparent de Broin (2000b) argued that the cavum pterygoidei of podocnemidids is homologous to the fossa pterygoidea of bothremydids and that the two are derived from the ‘‘podocnemidoid fossa’’ of Brasilemys. If this is correct, then the depression has occurred one time in the Pelomedusoides and been enlarged in the Podocnemididae and reduced and lost within most of the Bothremydidae. However, the distribution of the fossa in the MPC (fig. 305) shows that the fossa has originated five times within the Bothremydidae, all independently of the Podocnemididae. A similar but groovelike fossa occurs on the pterygoid of cheloniids (Gaffney, 1979a: fig. 210).</p> <p>The CI of this character in the MPC is 0.33, reflecting the high degree of homoplasy present in this character. A moderately developed fossa pterygoidea (state 1) originated three times and the deep fossa (state 2) three times within the Bothremydidae. There is no evidence from the cladogram (fig. 305) that the two states should be treated as additive, even though this might be expected from the morphology, that is, moderate (state 1) and deep (state 2).</p> <p>Discussion: Although the fossa pterygoidea is a prominent feature of the palate, it is too sporadic in distribution to be of much phylogenetic significance. The deep fossa unites (Foxemys, Polysternon) with (Nigeremys, Arenila), but the moderate condition seems to have arisen independently in each case. The fossa seems to be the attachment site of a portion of the pterygoideus muscle.</p> <p>A form of this character is used in Antunes and Broin (1988), Meylan (1996), Lapparent de Broin and Werner (1998), Tong et al. (1998), and Lapparent de Broin (2000b).</p> <p>69. Pterygoid, cavum pterygoidei: absent (Pelusios) 5 0; present (Podocnemis) 5 1.</p> <p>Morphology: Used by many previous authors, the cavum pterygoidei is a more formalized name for the ‘‘pterygoideus muscle chamber’’ or ‘‘enlarged carotid channel’’ of Gaffney (1979a: fig. 86). This is a relatively large opening from the palate into the braincase located at the posterior end of the pterygoid that contains a subdivision of the pterygoideus muscle (Schumacher, 1954, 1955a, 1955b, 1973). It is differentiated from the fossa pterygoidea, character 68, by having at least a partial covering ventrally and an anteromedial opening into the braincase.</p> <p>Primitive condition: All outgroups lack this character.</p> <p>Homoplasy: None known, but see Quadrate, fossa pterygoidea (character 68).</p> <p>Discussion: The two sister groups of the Podocnemididae, Brasilemys (Lapparent de Broin, 2000b) and Hamadachelys (Tong and Buffetaut, 1996), have a cavum pterygoidei that is hidden anteromedially by the underlapping basisphenoid medially and the pterygoid laterally. In these taxa the cavum is not as deep as in all other Podocnemididae, but the cavum pterygoidei is interpreted here as homologous in Hamadachelys, Brasilemys, and Podocnemididae.</p> <p>This character is used by Gaffney and Meylan (1988), Meylan (1996), Lapparent de Broin and Werner (1998), and Lapparent de Broin (2000b).</p> <p>70. Pterygoid, processus trochlearis pterygoidei: absent (Proganochelys) 5 0; present (Pelusios) 5 1.</p> <p>Morphology: The processus trochlearis pterygoidei (figs. 23, 24) is an important pleurodire synapomorphy described in Schumacher (1954, 1955a, 1955b, 1956) and Gaffney (1975 b, 1979a).</p> <p>Primitive condition: All turtles outside Pleurodira lack the processus entirely.</p> <p>Homoplasy: None known.</p> <p>Discussion: This is a synapomorphy for Pleurodira.</p> <p>This character is used in Gaffney and Meylan (1988), Gaffney et al. (1991), Rougier et al. (1995), Lapparent de Broin and Werner (1998), and Fuente and Iturralde-Vinent (2001).</p> <p>71. Pterygoid, posteroventral flange along lateral edge, medial to processus trochlearis pterygoidei: absent (Chelydra) 5 0; present (Pelusios) 5 1.</p> <p>Morphology: In pleurodires, the pterygoid forms a very thin sheet of bone, just medial to the processus trochlearis pterygoidei, which extends ventrally below the level of the rest of the pterygoid. These are figured in Gaffney (1979a: figs. 134, 142) and in figure 136B. Antunes and Broin (1988) Lapparent de Broin and Werner (1998) referred to this flange as a ‘‘pterygoid wing’’.</p> <p>Primitive condition: Proganochelys and cryptodires lack these.</p> <p>Homoplasy: None known.</p> <p>Discussion: Lapparent de Broin and Werner (1998) argued that the flange or wing is found in most pleurodires, but that bothremydids and Araripemys lack them. We have concluded, however, that the flange is present in all pleurodires and that its supposed absence in some is a consequence of preservation. The flange or wing is very thin and fragile, often being damaged or broken off entirely in recent pleurodire specimens. The flange does occur in better preserved specimens of Araripemys (THUg 1907, fig. 33B) and in a number of bothremydids: Bothremys maghrebiana (fig. 141B), Labrostochelys (fig. 193B), and Cearachelys (fig. 71B).</p> <p>72. Pterygoid, processus pterygoideus externus: without vertical plate (Pelusios) 5 0; with vertical plate (Chelydra) 5 1.</p> <p>See Gaffney et al. (1987), Gaffney et al. (1991), Rougier et al. (1995), and Gaffney (1996).</p> <p>73. Pterygoid, trigeminal ridge: absent (Galianemys) 5 0; ridge extending posteroventrally from foramen nervi trigemini to condylus mandibularis (Phosphatochelys) 51.</p> <p>Morphology: In Taphrosphys, Ummulisani, and Phosphatochelys a thin ridge extends from the ventral margin of the foramen nervi trigemini posteroventrally along the quadrate process of the pterygoid, to the vicinity of the condylus mandibularis (fig. 202). This ridge may be an attachment area for a part of the pterygoideus muscle.</p> <p>Primitive condition: All outgroups lack this character.</p> <p>Homoplasy: This character occurs only in Taphrosphys and Phosphatochelys.</p> <p>Discussion: This character supports the subgroup of Taphrosphyina consisting of Taphrosphys, Ummulisani, and Phosphatochelys.</p> <p>74. Pterygoid, position of the foramen posterius canalis carotici interni: in ventral surface of basisphenoid (Proganochelys) 5 0; in pterygoid-quadrate suture (Araiochelys) 5 1; in medial wall of basisphenoid (Kurmademys) 5 2; in prootic (Pelusios) 5 3; in pterygoid-basisphenoid (also prootic in some cases) suture (Euraxemys) 5 4; in pterygoidbasisphenoid-quadrate suture (Taphrosphys) 5 5; in quadrate only (Labrostochelys) 5 6.</p> <p>Morphology: The internal carotid artery of turtles enters the skull through the foramen posterius canalis carotici interni (Albrecht, 1967, 1976; Gaffney, 1979a), which may be located in the basisphenoid, adjacent palatoquadrate elements, or in sutures between these elements. In Proganochelys and Kayentachelys, the internal carotid enters the skull via the ventral surface of the basisphenoid (state 0; Gaffney, 1990: fig. 20). Pleurodires modify this direct entry by interposing other elements (see figs. 276 and 277 for all states of the foramen posterius canalis carotici interni in pleurodires). Phylogenetically, based on the MPC (fig. 296B), the first element to contain the foramen was the prootic. In chelids, pelomedusids, and Araripemys, the carotid enters the prootic before entering the basisphenoid so that the foramen posterius canalis carotici interni is formed in the prootic (state 3). This character is synapomorphic for Pleurodira in the MPC; of course it is not known in the shell-only taxa. In all pleurodires (except possibly Kurmademys), the carotid goes through the prootic, even though this may be covered ventrally by other bones.</p> <p>The formation of the foramen posterius canalis carotici interni by the basisphenoid and pterygoid (fig. 277A, state 4) occurs in Euraxemydidae, Podocnemididae, Sankuchemys, Cearachelyini, Arenila, and some Bothremydini, so that in the MPC this condition is primitive for Bothremydidae and a synapomorphy for the magnafamily Podocnemidera (fig. 296B). This makes morphologic sense as well because the large medial process of the quadrate seen in many Bothremydini and Taphrosphyini may be interpreted as a modification of state 4, with the quadrate covering some of the basisphenoid to produce a foramen posterius canalis carotici interni formed by the quadrate and pterygoid, recognized here as a different condition, state 1 (fig. 277B).</p> <p>In podocnemidids (Gaffney, 1979a: fig.86), Hamadachelys, and Brasilemys, the carotid enters the skull at the anterior margin of the cavum pterygoidei. The foramen posterius canalis carotici interni is formed mostly by the basisphenoid, but the pterygoid and prootic are close. This character could be interpreted as unique to this group, but we have included it in state 4 because the bones involved in it are the same as in other taxa with state 4.</p> <p>The three species of Taphrosphys, Bothremys kellyi, and Zolhafah have the foramen posterius canalis carotici interni formed at the junction of three bones: pterygoid, quadrate, and basisphenoid (fig. 277D, state 5).</p> <p>Kurmademys is unique in having the carotid enter the basisphenoid on a laterally facing surface that forms the anteromedial edge of a moderate fossa pterygoidea (state 2, fig. 63). This is morphologically distinct from the primitive chelonian condition (state 0) in being more laterally placed on a much wider basisphenoid. Scoring it as state 0, however, does not change the MPC.</p> <p>Labrostochelys (fig. 277F) (and one specimen of Ummulisani) is unique in having only the quadrate form the foramen posterius canalis carotici interni. Nonetheless, it is not very different morphologically from state 1, formation by pterygoid and quadrate, as the pterygoid is not far from the foramen in Labrostochelys. The quadrate has a suture extending from the foramen posterius canalis carotici interni to the pterygoid, suggesting that the canal is only barely covered by quadrate. A separate state, state 6, is created for the quadrate only. However, the condition in Labrostochelys is morphologically so similar to state 1, pterygoid plus quadrate, that Labrostochelys is scored as polymorphic. This decision does make a difference in the cladogram, however. Scoring both Labrostochelys and Ummulisani as state 6 makes the three species of Taphrosphys a multichotomy with the Ummulisani-Rhothonemys-Labrostochelys clade, reflecting the low support for the species of Taphrosphys.</p> <p>Teneremys (Broin, 1980: pl. 2) seems to have a foramen posterius canalis carotici interni formed by both basisphenoid and pterygoid (although this has not been substantiated), but it is unique in having the foramen at the anterior end of the basisphenoid.</p> <p>Primitive condition: The formation of the foramen posterius canalis carotici interni by a narrow basisphenoid as described in Gaffney (1990) is presumed to be primitive for turtles. Within Pleurodira, state 3, formation of the foramen by the prootic, is interpreted as primitive within this group.</p> <p>Homoplasy: Although this is a complex character (fig. 296B) with seven states, its CI is a respectable 0.5. None of the states reverses back to state 0. States 0 and 3 do not reverse at all, although they are each lost once. The more general state 4 is lost four times, possibly more. State 1 arises independently within Bothremydini and Taphrosphyini. State 5 arises three times. State 6 occurs in only Labrostochelys and one of three specimens of Ummulisani.</p> <p>Discussion: The formation of the internal carotid entry and its canal is more complex in pleurodires than in cryptodires (Gaffney, 1979a, 1996), and this character is only one way of coding this variation. The formation of a fossa pterygoidea or a cavum pterygoidei alters the bones around the foramen posterius canalis carotici interni, obscuring a more general similarity. Combining the quadrate plus pterygoid with prootic plus quadrate plus pterygoid condition into one state was done because the prootic is exposed when the fossa pterygoidea is present (see character 68, fossa pterygoidea).</p> <p>Some aspect of this character is used in Meylan (1996), Lapparent de Broin and Werner (1998), Tong et al. (1998), and Lapparent de Broin (2000b).</p> <p>75. Pterygoid, posterior margin of pterygoid forms part of foramen posterius canalis carotici interni: no, pterygoid does not enter foramen (Pelusios) 5 0; yes, pterygoid enters anterior margin of foramen (Galianemys) 5 1.</p> <p>Morphology: The pterygoid enters the anterior margin of the foramen posterius canalis carotici interni, apparently correlated with a posterior extension of the pterygoid (figs. 276, 277). Even in podocnemidids (Gaffney, 1979a: fig.86), the pterygoid enters into the formation of the foramen.</p> <p>Primitive condition: In chelids, pelomedusids, and Araripemys, the foramen posterius canalis carotici interni lies almost entirely within the prootic, sometimes with the basisphenoid entering it. In nearly all bothremydids the pterygoid is slightly more posterior and covers part of the foramen posterius canalis carotici interni. The more anterior position of the pterygoid posterior edge is primitive based on comparisons with Proganochelys.</p> <p>Homoplasy: Kurmademys and Labrostochelys have unique conditions of the foramen posterius canalis carotici interni and lack a pterygoid contribution.</p> <p>Discussion: In this analysis, this character is considered distinct from the preceding character 74, which also deals with the formation of the foramen posterius canalis carotici interni, because there are multiple patterns involving the foramen that are not expressed with only one character, even with multiple states. This character seeks to use the pattern that occurs in Euraxemydidae, Podocnemididae, and most Bothremydidae (fig. 306), that is, a slight posterior extension of the pterygoid reaching the foramen posterius canalis carotici interni. This condition seems to be a more general one (fig. 306) than the states identified in character 74 (fig. 296B); the other attempts to codify carotid variation. There are many carotid stories, and this is only one of them.</p> <p>76. Pterygoid, foramen caroticum laterale: present (Emydura) 5 0; absent (Pelusios) 5 1.</p> <p>Morphology: The foramen caroticum laterale is the anterior opening of the canalis caroticus lateralis (a lateral branch of the canalis caroticus internus) into the sulcus cavernosus that is usually just lateral to the foramen anterius canalis carotici interni and just medial to the foramen cavernosum (Gaffney, 1979a: 101; see also Albrecht, 1967, 1976). It is an opening in the dorsal surface of the pterygoid adjacent to the basisphenoid. This opening usually transmits the palatine artery. Its presence seems to be primitive for Pelomedusoides, as it is found in chelids and Araripemys (fig. 34); however, this is not well supported because of its absence in pelomedusids.</p> <p>Primitive condition: Proganochelys has a partially open cranioquadrate space, so the foramen caroticum laterale is not defined by bone (Gaffney, 1990). It is present in many casichelydians (Gaffney, 1979a: 101, figs. 54–65). Among pleurodires, it has been identified in Podocnemis, Peltocephalus, Erymnochelys, and all chelids except Chelus. It is considered to be absent in Pelusios and Pelomedusa (Albrecht, 1976).</p> <p>Homoplasy: The foramen caroticum laterale appears to have been lost at least three times within the Pleurodira: once in the genus Chelus, once in the Pelomedusidae, and at least once for the Bothremydidae.</p> <p>Discussion: This character can be scored only in specimens in which the braincase is very well preserved and has been prepared in detail. Thus, although the foramen caroticum laterale has yet to be found in bothremydids, its absence can be confirmed in only six species. Nonetheless, these six (Kurmademys, Cearachelys, Galianemys, Bothremys cooki, B. maghrebiana, and Taphrosphys sulcatus) include taxa in each tribe and are well distributed taxonomically.</p> <p>77. Pterygoid, midline contact: midline contact of pterygoids relatively long (Galianemys) 5 0; midline contact very short (Dirqadim) 5 1.</p> <p>Morphology: The pterygoids meet on the midline at their anterior end, anterior to the basisphenoid. In some taxa, the contact is very short (Labrostochelys, fig. 11G) and the basisphenoid is close to the palatines.</p> <p>Primitive condition: Most outgroups have a longer midline contact.</p> <p>Homoplasy: Rampant, with a CI of 0.14. Within pleurodires, the character arises independently six times in the MPC.</p> <p>Discussion: The only group this noisy feature supports is Nigeremys + Arenila.</p> <p>This character is used in Meylan (1996) and Lapparent de Broin (2000b).</p> <p>78. Epipterygoid, absent: present (Chelydra) 5 0; absent (Pelusios) 5 1.</p> <p>Morphology: Described and figured by Gaffney (1975a, 1975 b, 1979a, 1979b), this bone is absent in pleurodires and some cryptodires.</p> <p>Primitive condition: The bone is present in Proganochelys.</p> <p>Homoplasy: Epipterygoid loss or fusion occurs within cryptodires in baenids and Dermochelys, but apparently only once in pleurodires.</p> <p>Discussion: This character is a Pleurodira synapomorphy, but it is known only for taxa with good skulls, so it could be present from Pleurodira to Eupleurodira.</p> <p>This character is used by Gaffney and Meylan (1988) and Gaffney et al. (1991).</p> <p>79. Supraoccipital, supraoccipital-quadrate contact: absent (Pelusios) 5 0; present on dorsal surface of otic chamber (Bothremys) 5 1.</p> <p>Morphology: The otic region of turtles in dorsal view can be seen to be made up of contributions of four elements: the quadrate laterally, the prootic anteriorly, the supraoccipital medially, and the opisthotic posteriorly. Although there is variation in the contributions made by these elements, in nearly all turtles the prootic and opisthotic make contact and thus intervene between the supraoccipital and quadrate. In most bothremydids (fig. 143A) the supraoccipital and quadrate meet on the dorsal surface of the otic region, preventing contact of the prootic and opisthotic.</p> <p>The contacts of the otic chamber bones as seen on the dorsal surface do not necessarily reflect underlying contacts. As might be expected, the prootic-opisthotic contact is still present in some broken specimens, beneath the supraoccipital-quadrate contact.</p> <p>Primitive condition: Prootic-opisthotic contact occurs in Proganochelys and all relevant outgroups.</p> <p>Homoplasy: Although this is an important character in Bothremydidae (fig. 307), it has a low CI of 0.25. All bothremydids have a supraoccipital-quadrate contact except for Zolhafah and the Taphrosphyini, which represent reversals. Within the tribe Taphrosphyini, the undescribed skull CNRST-SUNY 199 is reversed to acquire the supraoccipital contact. No other pleurodires have the contact. However, some baenids (Gaffney, 1979a: fig. 56) have a supraoccipital-quadrate contact.</p> <p>Discussion: This character is a synapomorphy for the Bothremydidae, and its reversal is a synapomorphy for the Taphrosphyini (fig. 307).</p> <p>This character is used in Tong et al. (1998).</p> <p>80. Supraoccipital, crista supraoccipitalis: low to absent (Proganochelys) 5 0; a distinct sagittally oriented plate (Pelusios) 5 1.</p> <p>See Gaffney (1990), Gaffney and Kitching (1995), and Rougier et al. (1995).</p> <p>81. Supraoccipital, wide occipital plate: wide occipital plate with posteriorly concave depression (Proganochelys) 5 0; narrower occiput (Pelusios) 5 1.</p> <p>See Gaffney (1990), Gaffney and Kitching (1995), and Rougier et al. (1995).</p> <p>82. Exoccipital, foramen jugulare posterius: not formed in bone (Proganochelys) 5 0; formed by bone and open or partially closed (Galianemys) 5 1; completely closed by bone (Azabbaremys) 5 2.</p> <p>Morphology: The foramen jugulare posterius is an opening surrounded mostly by the exoccipital that leads into the recessus scalae tympani. When completely closed (state 2, fig. 195), the lateral margin of this foramen is usually formed by the exoccipital but sometimes by the opisthotic (fig. 203). The foramen may be open laterally and continuous with the fenestra postotica (figs. 46, 98).</p> <p>Primitive condition: The foramen jugulare posterius does not exist in bone in Proganochelys (Gaffney, 1990: 80). In most cryptodires it is enclosed by the exoccipital alone or by the exoccipital in combination with the opisthotic or pterygoid; in other cryptodires, it is continuous laterally with the fenestra postotica. Among living pleurodires it is closed laterally in Pelusios, Podocnemis, and in chelids other than Pseudemydura (Gaffney, 1979a). In Araripemys it is both open (fig. 36) and closed (fig. 37). In Euraxemys (fig. 46), it is open laterally. The fact that this opening is not defined by bone in Proganochelys has led us to score the open condition as primitive for turtles, but the closed condition seems to be primitive for pleurodires.</p> <p>Homoplasy: This is a variable character with a CI of 0.33, and it has undoubtedly undergone multiple reversals and/or multiple acquisitions. Morphologically, it would be expected that the open or less complete condition would be primitive to the closed, more ossified condition, and this seems to be the case for Cryptodira (Gaffney, 1996). However, the closed condition in chelids and pelomedusids, as well as in podocnemidids, Kurmademys, and some Araripemys, suggests that the reverse is true. The open condition occurs independently three times in Pleurodira: Euraxemydidae, Cearachelyini, and Foxemydina.</p> <p>Discussion: The open or reversed condition supports three groups in pleurodires (see above).</p> <p>This character is used in Lapparent de Broin and Werner (1998) and Lapparent de Broin (2000b).</p> <p>83. Exoccipital, recessus scalae tympani: not formed in bone (Proganochelys) 5 0; formed by bone, also forming fenestra perilymphatica (Pelusios) 5 1.</p> <p>See Gaffney (1990), Gaffney and Kitching (1995), and Rougier et al. (1995).</p> <p>84. Exoccipital, condylus occipitalis: basioccipital plus both exoccipitals (Euraxemys) 5 0; exoccipitals only (Pelusios) 5 1.</p> <p>Morphology: The occipital condyle in the tribes Taphrosphyini and Bothremydini is unusual in being made up of only the two exoccipitals (fig. 203) rather than the three bones in nearly all cryptodires (except Carettochelys) and most other pleurodires (except pelomedusids and Cearachelys). The bothremydid condyle often has a vertical cleft down its center marking the suture.</p> <p>Primitive condition: The outgroups Cryptodira, Chelidae, Araripemys, Euraxemydidae, Podocnemididae, and Kurmademys have three bones in the condylus occipitalis, the presumed primitive condition.</p> <p>Homoplasy: The CI of this character is 0.33. The complete exclusion of the basioccipital from the condylus occipitalis neck must originate three times in the MPC: in the Pelomedusidae, Cearachelys, and the infrafamily Bothremydodda (the tribes Taphrosphyini and Bothremydini). Galianemys has a wedge-shaped part of the basioccipital extending into the neck of the condylus occipitalis, almost to the articulating surface.</p> <p>Discussion: This character is used in Gaffney and Meylan (1988), Meylan (1996), and Tong et al. (1998), Lapparent de Broin and Murelaga (1999), and Lapparent de Broin (2000b).</p> <p>85. Exoccipital, exoccipital-quadrate contact: absent (Pelusios) 5 0; extensive, prootic absent (Galianemys) 5 1; narrow, prootic present (Euraxemys) 5 2; narrow, prootic absent (Brasilemys) 5 3.</p> <p>Morphology: In most pleurodires the quadrate does not extend all the way to the occipital region so that the prootic and opisthotic prevent contact between the quadrate and exoccipital. In bothremydids the quadrate does extend medially to reach the occipital elements and has broad contact with the basioccipital (character 59) and the exoccipital (state 1, fig. 88). There is also contact between the quadrate and exoccipital in Euraxemydidae (state 2, figs. 44, 53), but the morphology differs from that in bothremydids in that the prootic is exposed ventrally, the exoccipital has a unique ventral process (see character 86), and the quadrate-exoccipital contact is very narrow. Brasilemys has a third condition (state 3) in which the contact is narrow and the prootic is absent (Lapparent de Broin, 2000b).</p> <p>Primitive condition: Quadrate-exoccipital contact is absent in Proganochelys (Gaffney, 1990) and relevant outgroups, and thus this contact between these elements is considered derived.</p> <p>Homoplasy: If the state for Euraxemydidae is considered distinct from that in the bothremydids, there is no known homoplasy for the states in this character (fig. 308).</p> <p>Discussion: State 2 is synapomorphic for the Euraxemydidae and state 1 is synapomorphic for the Bothremydidae (fig. 308). Even though both states have ‘‘exoccipital-quadrate contact present’’, the differing morphologies suggest that these should not be ordered because the contact alone does not seem to be homologous.</p> <p>A version of this character is used in Lapparent de Broin (2000b).</p> <p>86. Exoccipital, ventral process: absent (Pelusios) 5 0; present (Euraxemys) 5 1.</p> <p>Morphology: In most turtles the exoccipital forms the lateral margins of the foramen magnum, the dorsolateral part of the occipital condyle, and the posteroventral part of the cavum cranii. It does not normally form part of the ventral surface of the skull. In Euraxemys and Dirqadim there is a unique condition in which a process of the exoccipital extends ventrally between the opisthotic and basioccipital and is exposed on the ventral surface lateral to the basioccipital (figs. 44, 46, 53).</p> <p>Primitive condition: The exoccipital of Proganochelys is excluded from participation in the ventral surface of the skull by prooticopisthotic contact ventral to the exoccipital. In most cryptodires, the basioccipital or pterygoid excludes the exoccipital from ventral exposure (but see Baena arenosa, Gaffney, 1979a: fig. 153), and in pleurodires some combination of contacts between the quadrate, basioccipital, prootic, and opisthotic prevents contribution of the exoccipital to the ventral surface. Thus, exclusion of the exoccipital from the ventral surface is clearly the primitive condition.</p> <p>Homoplasy: Some baenids (Gaffney, 1972a, 1979a) have a ventral exposure of the exoccipital, but its position and shape differ from euraxemydids. Brasilemys (Lapparent de Broin, 2000b) has apparently independently acquired this character. It also occurs as a variation in some chelids (Phrynops gibba PAM 2051, FMNH 45669 in fig. 147; Gaffney, 1979c). Araripemys (fig. 26) has a widely exposed exoccipital on the ventral surface correlated with a very narrow basioccipital.</p> <p>Discussion: This feature is a synapomorphy for Euraxemydidae.</p> <p>87. Basioccipital, basioccipital short: long, length/width of 0.60 or higher (Pelusios) 5 0; short, length/width of 0.59 or lower (Bothremys) 5 1.</p> <p>Morphology: The basioccipital of turtles is variable in shape but always makes up the posteriormost part of the ventral surface of the braincase. In most turtles it is approximately as long as wide. In bothremydids the basioccipital is comparatively short relative to its width (figs. 9–11), a clear difference from chelids, for example. However, this character could be judged as continuously variable with the distinction between ‘‘long’’ and ‘‘short’’ being subjective and perhaps arbitrary. A ratio of basioccipital length over width reveals a short gap so that ‘‘long’’ could be considered 0.60 and higher, with ‘‘short’’ being 0.59 and lower. Using this slight gap to differentiate the two states, podocnemidids and bothremydids are long. With one exception (Taphrosphys sulcatus), the Bothremydidae ratio varies from 0.31 (Chedighaii) to 0.57 (Cearachelys, Phosphatochelys). Podocnemidids (including Hamadachelys) are 0.59 or lower. The chelids,which are variable (we have chosen Emydura), are 0.64, but pelomedusids are higher at 0.70– 0.78. Euraxemydids are 0.73–0.77 and Araripemys is the highest at 1.2. Therefore, the closest ratios for the two states are podocnemidids at 0.59 and chelids at 0.64.</p> <p>Primitive condition: The pleurodiran outgroups are long in the basioccipital.</p> <p>Homoplasy: A simple character like this is difficult to test for homology, but the only reversal in the MPC is the relatively long basioccipital of Taphrosphys sulcatus at 0.68. Interestingly, the other two Taphrosphys species are 0.47 (T. congolensis) and 0.57 (T. ippolitoi), suggesting that this condition evolved within this genus.</p> <p>Discussion: Although a continuous character like this one could be divided into a number of states, we have chosen only two to try to reflect the short basioccipital of bothremydids. As a result, it seems that this feature is shared with podocnemidids, although choosing another division point could change that.</p> <p>This character or a version of it (‘‘telescoped occiput’’) is used in Antunes and Broin (1988), Lapparent de Broin and Werner (1998), and Lapparent de Broin (2000b).</p> <p>88. Basioccipital, basioccipital thick: basioccipital and basisphenoid relatively thick in cross section (Proganochelys) 5 0; thinner (Pelusios) 5 1.</p> <p>See Gaffney (1990) and Gaffney and Kitching (1995).</p> <p>89. Basioccipital, basioccipital-opisthotic contact: absent (Galianemys) 5 0; present (Pelomedusa) 5 1.</p> <p>Morphology: In most casichelydians, the opisthotic is excluded from contact with the basioccipital except in cases where the processus interfenestralis is well ossified ventrally (Gaffney, 1979a: 135–136). In certain pleurodires, there is a ventral process of the opisthotic that is posterior to the processus interfenestralis that makes a strong, sutured contact with the basioccipital between the foramen jugulare posterius and the fenestra postotica (Gaffney, 1979a: figs. 85, 86). Among pleurodires, this contact is present in most but not all Chelidae (Gaffney, 1979a: fig. 88), but not in Phrynops gibba PAM 2051 or in Chelodina (Gaffney, 1979a: 136) in which the exoccipital intervenes. It is present in the Pelomedusidae (fig. 21) and Podocnemididae as well as Hamadachelys. The contact is absent in all Bothremydidae.</p> <p>Primitive condition: In Proganochelys the opisthotic makes a ventromedial contact with the basioccipital. Although the exact position of the suture is unclear (Gaffney, 1990: 86), it is posterior to the processus interfenestralis and may be homologous to the contact seen in several pleurodiran groups. Whether the condition in Proganochelys is homologous (we have scored it as questionable), this sutured posterior contact in members of the Chelidae, Pelomedusidae, and Podocnemididae (plus Hamadachelys) suggests that the presence of this contact may be primitive for pleurodires, although this is equivocal.</p> <p>Homoplasy: Opisthotic–basioccipital contact between the foramen jugulare posterius and the fenestra postotica occurs in some cryptodires. It has arisen independently in podocnemidids. The CI is 0.5.</p> <p>Discussion: The distribution of this character among the Pleurodira suggests that it has been gained twice or lost three times. In either case, it is uniformly absent in the Bothremydidae although it is present in the sister group, the Podocnemidinura.</p> <p>A version of this character is used in Lapparent de Broin (2000b).</p> <p>90. Prootic, hyomandibular branch of facial nerve lies in its own canal: no (Chelydra) 5 0; yes (Podocnemis) 5 1.</p> <p>Morphology: Described and figured in Gaffney (1975 b, 1979a), determining this character requires access to the canalis cavernosus and the internal morphology of the prootic. A short canal contains the hyomandibular nerve, separating it from the canalis cavernosus.</p> <p>Primitive condition: The absence of a canal is the condition in Proganochelys and Cryptodira.</p> <p>Homoplasy: None known.</p> <p>Discussion: This character is a synapomorphy for the Pleurodira. Despite the fact that it can only be seen in well-preserved and partially disarticulated skulls, it is included. It is determinable in some fossils; Galianemys and Dirqadim are known from CT scans.</p> <p>This character is used by Gaffney and Meylan (1988) and Gaffney et al. (1991).</p> <p>91. Prootic, foramen stapedio-temporale: not a canal (Proganochelys) 5 0; a distinct foramen and canal (Pelusios) 5 1.</p> <p>See Gaffney et al. (1987), Gaffney et al. (1991), and Gaffney (1996).</p> <p>92. Prootic, foramen stapedio-temporale opens anteriorly: no (Pelusios) 5 0; yes (Galianemys) 5 1.</p> <p>Morphology: The foramen stapedio-temporale lies on the anterior surface of the otic chamber in most bothremydids. Compared with the outgroups, the foramen is placed more anteroventrally in the prootic-quadrate suture. When the skull is seen in dorsal view, there is either no sign of the foramen or only a narrow part of the margin (figs. 7,8). This depends to a certain extent on how the skull is oriented, but unless the skull is strongly tilted, the foramen margins usually cannot be seen. If an extensive skull roof covers the otic chamber, some rotation of the skull must be done to see the position of the foramen stapedio-temporale.</p> <p>Primitive condition: In the pleurodire outgroups Chelidae, Pelomedusidae (fig. 21A), Euraxemydidae (fig. 45), and Podocnemididae, the foramen stapedio-temporale is visible in dorsal view because it is in a more posterodorsal position than in the Bothremydidae.</p> <p>Homoplasy: The subfamily Bothremydinae (consisting of the tribes Cearachelyini, Taphrosphyini, and Bothremydini) has this character (fig. 309). Kurmademys has the primitive condition, but Sankuchemys may have the derived condition. Unfortunately, Sankuchemys is badly crushed and the presence or absence of the foramen is ambiguous. However, the otic chamber is crushed directly dorsoventrally, and there is no sign of the foramen stapedio-temporale on either side. In the character set Sankuchemys is coded as missing for this character.</p> <p>Discussion: Despite the ambiguity in Kurmademydini, this character is definitely found only in the subfamily Bothremydinae (fig. 309) and is a synapomorphy for it.</p> <p>This character is used in Meylan (1996) and Tong et al. (1998).</p> <p>93. Prootic, foramen stapedio-temporale and foramen nervi trigemini: separated by most of prootic (Pelusios) 5 0; separated by narrow bar of prootic (Bothremys) 5 1.</p> <p>Morphology: In the bothremydid tribes of Bothremydini and Taphrosphyini, the foramen stapedio-temporale lies on the anterior surface of the otic chamber, separated from the foramen nervi trigemini by a thin bar of prootic (fig. 132F). In these taxa, the foramen stapedio-temporale is mostly formed by the prootic, with a narrow part of quadrate entering the margin. The foramen itself is usually close to the center of the prootic along its ventral edge. In many specimens the prootic bar is broken away, but the position of the foramen is still determinable.</p> <p>Primitive condition: The pleurodiran outgroups show a foramen stapedio-temporale and foramen nervi trigemini separated by most of the prootic to be the primitive condition.</p> <p>Homoplasy: None known.</p> <p>Discussion: As this character requires the foramen stapedio-temporale to be on the anterior surface of the otic chamber, it could be coded as a third state in the preceding character: foramen stapedio-temporale not visible in dorsal view. When the character states are ordered, it produces the same MPC.</p> <p>94. Prootic, ventral exposure: most of prootic exposed ventrally (Emydura) 5 0; prootic about half covered by quadrate and basisphenoid (Euraxemys) 5 1; nearly all of prootic covered by quadrate, basisphenoid, and pterygoid (Taphrosphys) 5 2.</p> <p>Morphology: In euraxemydids the basisphenoid and quadrate cover most of the prootic, leaving only a narrow exposure of prootic (state 1, fig. 44). In podocnemidids and bothremydids the prootic is completely covered (except for a small exposure described as another character, Prootic, ventral exposure 2). This is state 2 (fig. 277).</p> <p>Primitive condition: Proganochelys has a completely exposed prootic (Gaffney, 1990). Chelids and pelomedusids (figs. 21, 276) also have this condition, although other bones encroach on the prootic.</p> <p>Homoplasy: None. Cryptodires also cover the prootic ventrally, but it is done entirely by the pterygoid and appears to be nonhomologous (Gaffney, 1975 b, 1979a).</p> <p>Discussion: The partial covering of the prootic in euraxemydids is very similar to the complete covering in other pleurodires, as it involves a lateral extension of the basisphenoid and a medial extension of the quadrate. This character could be run ordered because state 1 is additive with respect to state 2 (fig. 310). All taxa that have state 2 also have state 1, so to run them as separate characters would lose this information. However, running this character unordered results in the same MPC (fig. 310).</p> <p>This character is used in Antunes and Broin (1988), Meylan (1996), Lapparent de Broin and Werner (1998), and Tong et al. (1998).</p> <p>95. Prootic, quadrate-pterygoid-basisphenoid exposure: complete exposure of prootic or no exposure of prootic (Pelusios) 5 0; exposure of prootic small, surrounded by pterygoid, basisphenoid, and quadrate, with foramen nervi facialis exposed (Kurmademys) 5 1.</p> <p>Morphology: In the bothremydids Kurmademys, Sankuchemys, Cearachelys (not all specimens, see Cearachelys), and Galianemys emringeri, there is a small, irregular exposure of the prootic at or near the junction of the pterygoid, basisphenoid, and quadrate (fig. 277E). This exposure surrounds or nearly surrounds the foramen nervi facialis, which is therefore visible in ventral view in these forms, in contrast to other bothremydids.</p> <p>Primitive condition: The primitive condition for prootic exposure is widely exposed, as in chelids and pelomedusids, but in this character we identify as primitive all other prootic conditions that lack the character as specified.</p> <p>Homoplasy: In the MPC (fig. 311), this character appears at least three and possibly four times independently, and it has a CI of 0.33. Elsewhere (character 68, fossa pterygoidea, fig. 305) we argue that at least in some cases the exposure of the prootic is the result of a deep fossa pterygoidea that has eroded the basisphenoid, pterygoid, and quadrate, exposing the underlying prootic.</p> <p>Discussion: The high degree of homoplasy and the frequent (but not exclusive) association of the prootic exposure with a deep fossa pterygoidea suggest it may not be homologous everywhere it appears. However, Kurmademys has a moderate fossa and a prootic exposure, and Sankuchemys has the exposure but no evidence of a fossa (although the only known skull is crushed). In the MPC the small exposure is a synapomorphy for the tribe Kurmademydini (fig. 311).</p> <p>96. Prootic, processus trochlearis oticum: absent (Proganochelys) 5 0; present (Chelydra) 5 1.</p> <p>See Gaffney et al. (1987), Gaffney et al. (1991), Gaffney (1996), and Rougier et al. (1995).</p> <p>97. Prootic, plane of fenestra ovalis: inclined from the vertical (Proganochelys) 5 0; very close to vertical (Chelydra) 5 1.</p> <p>See Gaffney (1990), Gaffney and Kitching (1995), and Rougier et al. (1995).</p> <p>98. Opisthotic, processus interfenestralis expanded ventrally: narrow ventrally (Proganochelys) 5 0; expanded ventrally (Pelusios) 51.</p> <p>See Gaffney (1990).</p> <p>99. Opisthotic, processus interfenestralis covered in ventral view: exposed ventrally (Emydura) 5 0; covered by bone (Bothremys) 51.</p> <p>Morphology: The processus interfenestralis (Gaffney, 1972 b, 1979a) of the opisthotic is visible in ventral view in chelids, pelomedusids, and Araripemys (fig. 276). This is correlated with portions of the cavum labyrinthicum, fenestra ovalis, and recessus scalae tympani also being open ventrally. In life, this area is filled with cartilage in chelids and pelomedusids (Gaffney, 1979a). In euraxemydids, podocnemidids, and bothremydids, a medially large quadrate and posterolaterally large basisphenoid cover this area with bony ossification (figs. 276, 277).</p> <p>Primitive condition: The exposed condition of chelids and pelomedusids is closest to the completely open condition in Proganochelys and is presumed to be primitive for pleurodires.</p> <p>Homoplasy: None known, except for within Selmacryptodira.</p> <p>Discussion: It might be possible to break the derived state into two states, including one for euraxemydids, which can be interpreted as having a smaller medial quadrate process than do podocnemidids and bothremydids. If ordered, no information would be lost. However, judging the difference in size of the medial quadrate process seems too subjective, even for me.</p> <p>This character is used in Lapparent de Broin and Werner (1998), Lapparent de Broin and Murelaga (1999), and Lapparent de Broin (2000b).</p> <p>100. Opisthotic, fenestra postotica closed medially: open medially (Euraxemys) 5 0; closed medially by opisthotic-quadrate contact (Taphrosphys) 5 1.</p> <p>Morphology: The fenestra postotica (Gaffney, 1972 b, 1979a) is limited laterally and ventrally by the quadrate and dorsally by the opisthotic. When the opisthotic and quadrate meet medial to the fenestra postotica, it is closed (figs. 132D, 218). Only the Cearachelyini (figs. 87, 88, 98–100) among bothremydids have a medially open fenestra postotica.</p> <p>Primitive condition: All the pleurodiran outgroups have a medially open fenestra postotica.</p> <p>Homoplasy: In the MPC, the closed condition evolved twice, once in Kurmademys (Sankuchemys is unknown) and once in the infrafamily Bothremydodda (the tribes Taphrosphyini and Bothremydini), or it was lost once in the tribe Cearachelyini.</p> <p>Discussion: This character is independent of a laterally closed foramen jugulare posterius. Chelids and pelomedusids have a laterally closed foramen jugulare posterius with an open fenestra postotica.</p> <p>This character or a version of it was used in Lapparent de Broin and Werner (1998) and Lapparent de Broin (2000b).</p> <p>101. Opisthotic, fenestra postotica short horizontal slit: more open dorsoventrally (Euraxemys) 5 0; short slit (Galianemys) 5 1.</p> <p>Morphology: The Cearachelyini have a uniquely shaped fenestra postotica. The fenestra postotica is open medially, and it is dorsoventrally compressed in comparison to other pleurodires. The result appears as a short slit (figs. 87, 88, 98–100), in contrast to the round or oval opening of other bothremydids.</p> <p>Primitive condition: A more open condition is in all relevant outgroups and is presumed primitive.</p> <p>Homoplasy: None known.</p> <p>Discussion: This character is a synapomorphy for the tribe Cearachelyini. This character could be a state within the closed fenestra postotica character, but it would be confusing, at least to me.</p> <p>102. Opisthotic, processus paroccipitalis: projects posteriorly beyond squamosal (Euraxemys) 5 0; smaller, does not project beyond squamosal (Galianemys) 5 1.</p> <p>Morphology: The variation in shape of the opisthotic-squamosal area of the occiput in pleurodires is a source of characters, but some are hard to define. This character is an attempt to reflect the small size of the processus paroccipitalis (Gaffney, 1972 b, 1979a) in bothremydids as a character. It is compared to the size of the squamosal, although this is not entirely satisfactory as some taxa (e.g., Labrostochelys) have very long squamosals. The character is best seen in figures 9–11.</p> <p>Primitive condition: The condition in Proganochelys (Gaffney, 1990) is presumed to be primitive, with the processus paroccipitalis projecting posteriorly. However, Proganochelys has a unique morphology (among turtles), and the squamosal is very small. Cryptodires and chelids have a larger squamosal with a smaller processus paroccipitalis, and this may be primitive for pleurodires. Nonetheless, pelomedusids, Araripemys, euraxemydids, and podocnemidids have a long, projecting processus paroccipitalis, and it is possible that this is the primitive condition.</p> <p>Homoplasy: The small processus paroccipitalis has originated twice in the MPC, once (possibly twice) within cryptodires and in chelids and once in bothremydids, being reversed in all other pleurodires. However, the reversed condition in pleurodires is morphologically distinct from the Proganochelys condition.</p> <p>Discussion: Although it gets a little fuzzy around cryptodires, chelids, and Proganochelys, this character is a bothremydid synapomorphy.</p> <p>103. Opisthotic, thin horizontal flange: absent (Galianemys) 5 0; thin horizontal flange present on posterior edge of opisthotic just dorsal to fenestra postotica (Chedighaii hutchisoni) 5 1.</p> <p>Morphology: Best seen in Chedighaii hutchisoni (fig. 159), KUVP 14765, this thin flange lies ventral to the distinct curve or ‘‘step’’ as the opisthotic curves from a horizontal surface ventrally to a vertical surface. The flange is so distinct in Chedighaii that it has a shallow, horizontal groove above it. Below the flange is the fenestra postotica. In C. barberi, Alabama 2001.2, the flange is broken off on both sides but its base is clear and is nearly identical to that in KUVP 14765.</p> <p>Primitive condition: All other pleurodires and Proganochelys lack this flange.</p> <p>Homoplasy: None known, except that among the five skulls of Bothremys maghrebiana the flange is variable.</p> <p>Discussion: Chelids and pelomedusids may have a narrow posterior margin to the processus paroccipitalis of the opisthotic, but this condition is distinct from the Chedighaii / Bothremys condition.</p> <p>104. Basisphenoid, basisphenoid-quadrate contact: absent 5 0; present and wide, as in Galianemys 5 1; present and narrow, as in Azabbaremys 5 2.</p> <p>Morphology: The basisphenoid-quadrate contact is a Podocnemidoidea (Podocnemididae + Bothremydidae) synapomorphy, known for some time (Lapparent de Broin and Werner, 1998; Lapparent de Broin, 2000b). Examination of its distribution in the Bothremydidae (figs. 9–11) suggests that two states can be distinguished, a broader contact (as in Galianemys, fig. 81B) and a narrower contact (as in Azabbaremys, fig. 212B). As in all of these more subjective states, there is an arbitrary element to determining which state is present.</p> <p>Primitive condition: The absence of a contact in nearly all of the relevant outgroups indicates that this is the primitive state. Some Pelusios may have the contact as an individual variation.</p> <p>Homoplasy: None known for the presence of a contact (except some Pelusios). However, the two states in the MPC (fig. 312) show two origins and a loss for state 2, the narrow contact, once in Bothremys + Chedighaii and once for Taphrosphyini, with a reversal in Taphrosphys + Ummulisani + Phosphatochelys. However, Phosphatochelys shows variation in this feature and it has been coded with both states. The CI is 0.5.</p> <p>Discussion: There may be some ambiguity in discriminating a few taxa, such as Phosphatochelys, regarding the two derived states, but it still seems worthwhile to extract this information and reflect it in the datasets. The character can also be run as a simple presence or absence of the contact; this is a synapomorphy for Bothremydidae (fig. 312).</p> <p>This character is used in Lapparent de Broin and Werner (1998) and Lapparent de Broin (2000b).</p> <p>105. Basisphenoid, interpterygoid vacuity: large and open (Proganochelys) 5 0; small or absent (Pelusios) 5 1.</p> <p>See Gaffney (1990), Gaffney et al. (1991), Gaffney and Kitching (1995), and Rougier et al. (1995).</p> <p>106. Basisphenoid, ventral outline: elongate, basisphenoid not sutured to pterygoids (Proganochelys) 5 0; more triangular (baenids) 5 1; more pentagonal (Taphrosphys) 5 2; very elongate (Araripemys) 5 3; V-shaped pointing anteriorly (Arenila) 5 4.</p> <p>Morphology: The shape of the basisphenoid as seen in ventral view varies, and this character set is an attempt to identify some of this variation. In most bothremydids (figs. 9– 11) the basisphenoid is triangular, with the base and the anterolateral contacts with the pterygoid being dominant (state 1, 9H). The shape can also be more pentagonal (state 2, fig. 11B), with the quadrate contact being much longer and the pterygoid contact shorter. The pentagonal (state 2) occurs in chelids, pelomedusids, podocnemidids, the Kurmademydini, Foxemys + Polysternon, and Taphrosphys. Araripemys is unique in having a very elongate basisphenoid (state 3, fig. 9C). In Nigeremys and Arenila, the basisphenoid is V-shaped or arrow-shaped (state 4, fig. 11I), with its posterior margin embayed, concave posteriorly.</p> <p>Primitive condition: Although not exactly comparable to casichelydians due to the absence of a sutured pterygoid, Proganochelys has a roughly triangular shape, but it lacks the flat ventral surface and contacts of other turtles and is coded as a separate state. Cryptodires are scored triangular, and this is the outgroup for the pleurodires. However, the pentagonal shape (state 2) is in chelids and pelomedusids.</p> <p>Homoplasy: The CI is 0.44 and there is a fair amount of homoplasy within bothremydids.</p> <p>The V-shaped state 4 is unique to Nigeremys + Arenila, and state 3 is unique to Araripemys. The pentagonal state 1, however, is more complex. In the MPC, it is primitive for pleurodires and lost or reversed in Araripemys, euraxemydids, and Cearachelyini + Bothremydini + Taphrosphyini. It appears independently in Foxemys + Polysternon and the genus Taphrosphys.</p> <p>Discussion: The pentagonal basisphenoid is a way of wresting information from the extent of quadrate-basisphenoid contact. Such a simple character is hard to homologize and is somewhat subjective. Phosphatochelys has a more irregularly shaped basisphenoid that could be considered pentagonal, but we have scored it triangular. Thus, there are some ambiguities in this state. The V-shaped basisphenoid of Arenila and Nigeremys is quite different from other taxa.</p> <p>107. Basisphenoid, processus clinoideus: present, with abducens canal (Pelusios) 5 0; processus clinoideus absent, canal is a groove (Bothremys) 5 1.</p> <p>Morphology: In Bothremys and Chedighaii barberi the small, spurlike processus clinoideus (Gaffney, 1972 b, 1979a) is not ossified and the rim of the sella turcica and the dorsum sellae is a smooth edge (fig. 134). Just lateral to the dorsum sellae is a shallow groove that seems to be for the abducens nerve. This condition is visible in Bothremys cooki, AMNH 2521; B. maghrebiana, AMNH 30041; and in the endocast of a presumed Chedighaii barberi, YPM PU 12951.</p> <p>Primitive condition: The processus clinoideus and foramen nervi abducentis are found in all other pleurodires and Proganochelys.</p> <p>Homoplasy: None known at present, given the current MPC. However, the dorsal surface of the basisphenoid is determinable only in eight other bothremydid species.</p> <p>Discussion: The dorsal surface of the basisphenoid is not visible in Bothremys arabicus, Chedighaii hutchisoni, and Araiochelys, which makes this character known in only about half of the important taxa, so there are many missing data.</p> <p>108. Basisphenoid, skull akinetic: no, basipterygoid articulation present (Proganochelys) 5 0; yes, basipterygoid articulation sutured (Australochelys) 5 1.</p> <p>See Gaffney (1990), Gaffney et al. (1991), Gaffney and Kitching (1995), and Rougier et al. (1995).</p> <p>109. Basisphenoid, cultriform process: rodlike, thin (Proganochelys) 5 0; broad, flat, covered ventrally (Australochelys) 5 1.</p> <p>See Gaffney (1990) and Gaffney and Kitching (1995).</p> <p>110. Basisphenoid, sella turcicałdorsum sellae: deep, well-defined margins (Bothremys) 5 0; very shallow, low margins (Taphrosphys sulcatus) 5 1.</p> <p>Morphology: Nearly all pleurodires have a well-defined and relatively deep sella turcica concavity with a distinct dorsum sellae at its posterior margin (Gaffney, 1979a). In two species of Taphrosphys, T. sulcatus and T. ippolitoi, the sella is very low, being barely recognizable, and the dorsum sellae is not significantly above the floor of the sella turcica (fig. 174).</p> <p>Primitive condition: The deep, well-defined sella turcica occurs in chelids, pelomedusids, and other outgroups and is the presumed primitive condition.</p> <p>Homoplasy: None known.</p> <p>Discussion: Although this character resolves the three species of Taphrosphys, the few bothremydid taxa for which it is known, particularly among the other Taphrosphyini, make its use questionable and it has been deleted in some of the analyses. When deleted, the three species are a multichotomy.</p> <p>111. Basisphenoid, ventral tubercle: single tubercle formed by basisphenoid and basioccipital (Proganochelys) 5 0; paired tubercles (Australochelys) 5 1; no tubercle (Pelusios) 5 2.</p> <p>See Gaffney (1990) and Rougier et al. (1995).</p> <p>112. Columella auris, footplate: footplate absent, stapes thick (Proganochelys) 5 0; wide footplate present, stapes thin (Pelusios) 5 1.</p> <p>See Gaffney (1990) and Gaffney and Kitching (1995).</p> <p>113. Splenial: present (Proganochelys) 5 0; absent (Pelusios) 5 1.</p> <p>Morphology: The splenial bone (Gaffney, 1979a) lies on the medial surface of the lower jaw, anterior to and slightly separating the prearticular and angular. It is missing in all pleurodires except Chelidae. In these forms, the angular and prearticular tend to extend anteriorly, filling the space occupied by the splenial in chelids (fig. 241).</p> <p>Primitive condition: A large splenial is present in Proganochelys (Gaffney, 1990), the presumed primitive condition.</p> <p>Homoplasy: None known within pleurodires.</p> <p>Discussion: Due to lack of lower jaws and the need of a well-preserved specimen to determine the absence of a splenial, the character can be scored in only four bothremydids. Nonetheless, it remains as a Pelomedusoides synapomorphy.</p> <p>This character is used in Gaffney and Meylan (1988), Meylan (1996), and Lapparent de Broin (2000b).</p> <p>114. Dentary, high lingual ridge: absent (Pelusios) 5 0; present (Bothremys) 5 1.</p> <p>Morphology: The lingual ridge in bothremydids like Bothremys, Kurmademys, Cearachelys, and Foxemys is higher and deeper than the labial ridge (fig. 241). It is about the same height (or even lower) anteriorly, and it rises posteriorly to be wedge-shaped in lateral view.</p> <p>Primitive condition: All the outgroups have both lingual and labial ridges of equal size or have a higher labial ridge. We have not distinguished these conditions.</p> <p>Homoplasy: A high lingual ridge is present in the Cearachelyini, Kurmademydini, and Bothremydini, but it is reversed in Taphrosphyini. The living podocnemidids also have a larger lingual ridge, but fossil taxa vary. Hamadachelys has a lower jaw with both ridges nearly the same, but the lingual is slightly higher than the labial, an appropriate primitive condition. It is possible that a higher lingual ridge is primitive for Podocnemididae and could be argued as primitive for Podocnemididae + Bothremydidae, but at present, it is more likely to have appeared independently within Podocnemididae and Bothremydidae.</p> <p>Discussion: The principal difficulty with this character is the few lower jaws available for bothremydids and other pleurodires. Nonetheless, the known jaws are representative of the bothremydid tribes.</p> <p>115. Dentary, dentary pits: absent (Euraxemys) 5 0; present (Bothremys) 5 1.</p> <p>Morphology: The pitted lower jaws were first described by Leidy (1865) in Bothremys cooki (fig. 19), and later by Hay (1908). Gaffney and Zangerl (1968) redescribed B. cooki and added the lower jaws of ‘‘ Bothremys ’’ barberi (here referred to Chedighaii barberi). The conical pits (fig. 239) are concave anteriorly. The pits are known in Araiochelys, B. cooki (fig. 239), B. maghrebiana (fig. 241), and Chedighaii barberi.</p> <p>Primitive condition: The absence of pits is primitive.</p> <p>Homoplasy: None known.</p> <p>Discussion: In Chedighaii barberi, the lower jaw has pits but the maxilla does not. In the other forms with lower jaw pits, there are also pits in the maxilla. This lack of complete correspondence is the rationale, however dubious, for recognizing separate characters in the lower jaw and the skull.</p> <p>116. Dentary, U-shaped lingual ridges on symphysis: absent (Euraxemys) 5 0; present (Bothremys) 5 1.</p> <p>Morphology: In bothremydids the lingual ridge of the dentary is higher than the labial ridge and is strongly developed. In some, the pair of lingual ridges join to form a U-shaped ridge on the dentary at the symphysis (figs. 241, 247). The jaw edges are not parallel to the labial ridges. The U-shaped ridge may be excavated medially, as in Bothremys maghrebiana and Araiochelys, or it may be filled with bone to form a wedge, as in Bothremys cooki (see also fig. 247, a Madagascar lower jaw described in Gaffney and Forster, 2003).</p> <p>Primitive condition: The U-shaped symphyseal ridge is absent in Proganochelys, chelids, Araripemys, and Euraxemys. In the Podocnemididae there are strong lingual ridges that are taller than the labial ridges. but they form a V-shaped rather than a Ushaped ridge with a pointed apex.</p> <p>Homoplasy: A U-shaped ridge like that in most bothremydids also occurs in some Pelusios. There is a reversal within the Taphrosphyini (see Discussion).</p> <p>Discussion: A U-shaped ridge on the symphysis appears to be a synapomorphy for the Bothremydidae that is lost within the tribe Taphrosphyini. The distribution of lower jaws in the Taphrosphyini is too poorly known to be certain where this reversal occurs.</p> <p>117. Dentary, symphysis: fused (Bothremys) 5 0; sutured (Euraxemys) 5 1.</p> <p>Morphology: The symphysis between the two dentaries is normally fused in turtles with no evidence of a suture. In a few members of the Pleurodira the two dentaries are sutured in the midline instead of being fused. The symphysis is sutured in Araripemys, Euraxemys (figs. 231, 232), Pelomedusa, some Pelusios, and the chelid genera Platemys, Phrynops, Chelus, Chelodina, and Hydromedusa (Gaffney, 1979a).</p> <p>Primitive condition: The fused condition seen in Proganochelys and all cryptodires is presumably the primitive condition.</p> <p>Homoplasy: In the MPC, the character distribution is ambiguous due to polymorphism within chelids and pelomedusids. The CI is 0.5 but the character is reversed within the Chelidae and Pelomedusidae.</p> <p>Discussion: Sutured rami are found in Araripemys and Euraxemys and were used by Meylan (1996) to unite them in a family Araripemydidae. However, in the MPC this character is polymorphic in chelids and pelomedusids. The chelid distribution suggests that if Gaffney (1977b) is correct, the fused condition is primitive for chelids. In pelomedusids it is fused only in some Pelusios, so the sutured condition may be primitive for this group plus Araripemys. If this interpretation is correct, the sutured condition evolved once within chelids and once for all remaining pleurodires, being reversed for the Podocnemidoidea (the families Podocnemididae + Bothremydidae).</p> <p>This character is used in Meylan (1996) and Lapparent de Broin (2000b).</p> <p>118. Dentary, triturating surfaces: relatively narrow (Euraxemys) 5 0; wide posteriorly (Cearachelys) 5 1.</p> <p>Morphology: Many bothremydids have a lower jaw with a triangular-shaped surface that is much wider posteriorly than anteriorly (fig. 241).</p> <p>Primitive condition: Relatively narrow jaws, with labial and lingual ridges that are more nearly parallel to each other, are present in the outgroups.</p> <p>Homoplasy: Podocnemidids evolve broad lower jaws, but these do not have the same morphology as bothremydids. The CI is 0.33, and the character is reversed in Araiochelys and the Taphrosphyini, which have narrower jaws. Araiochelys, however, is still very similar to Bothremys, just narrower. The Taphrosphyini, though, do have a very narrow triturating surface that is morphologically distinct form other bothremydids to the extent they are known.</p> <p>Discussion: Although lower jaws are represented by many missing data, they are known for each major group (tribes). The triangular or wide shape is synapomorphic for the Bothremydidae, and the reversed, narrow shape is synapomorphic for the Taphrosphyini.</p> <p>119. Dentary, widely exposed on lateral surface: yes, widely exposed posteriorly (Euraxemys) 5 0; no, covered posteriorly by surangular (Bothremys) 5 1.</p> <p>Morphology: The surangular and coronoid in the tribes Bothremydini and Taphrosphyini are extensively exposed on the lateral surface of the jaw ramus (fig. 241), so that the dentary exposure is relatively small.</p> <p>Primitive condition: The outgroups have broad exposure of the dentary posteriorly.</p> <p>Homoplasy: A widely exposed dentary also occurs in the Podocnemididae (fig. 313) but not in Hamadachelys or Brasilemys.</p> <p>Discussion: This character (fig. 313) is a synapomorphy for the infrafamily Bothremydodda (the tribes Bothremydini and Taphrosphyini).</p> <p>120. Surangular, foramen nervi auriculotemporalis: absent (Proganochelys) 5 0; present (Podocnemis) 5 1.</p> <p>Morphology: The foramen nervi auriculotemporalis (fig. 232C, see also Gaffney, 1979a) lies at the posterolateral end of the lower jaw in the surangular. Its absence results in a smooth lateral surface on the surangular (fig. 241).</p> <p>Primitive condition: The foramen is widely present in pleurodire outgroups and cryptodires, but it seems to be absent in Proganochelys.</p> <p>Homoplasy: None, other than a reversal for the infrafamily Bothremydodda.</p> <p>Discussion: The absence of the foramen nervi auriculotemporalis is a synapomorphy for the infrafamily Bothremydodda (Bothremydini + Taphrosphyini).</p> <p>121. Coronoid, wide lateral exposure: no (Euraxemys) 5 0; yes (Bothremys) 5 1.</p> <p>Morphology: In the Bothremydini, the coronoid is exposed ventrolaterally and anteroventrally on the lateral surface of the jaw (fig. 241C).</p> <p>Primitive condition: The coronoid is typically not exposed widely on the lateral surface of the jaw (fig. 232C). This condition is in Proganochelys and most pleurodire outgroups.</p> <p>Homoplasy: Araripemys independently acquires a wide coronoid in the MPC.</p> <p>Discussion: Unfortunately, none of the Taphrosphyini lower jaws is well enough preserved to allow determination of this character. It only occurs in the tribe Bothremydini within the Bothremydidae.</p> <p>122. Prearticular, fossa meckelii open anteriorly: no, closed by long angular-prearticular contact (Euraxemys) 5 0; yes, short prearticular-angular contact (Bothremys) 5 1.</p> <p>Morphology: In the lower jaw of most turtles the sulcus cartilaginis meckelii is closed ventrally by the prearticular and angular, which meet in a long suture medial to the sulcus. In the tribes Bothremydini and Taphrosphyini, much of the fossa meckelii is open anteriorly, and the prearticular-angular contact is short (fig. 241D).</p> <p>Primitive condition: The condition in Proganochelys, in which the prearticular-surangular suture begins below the fossa meckelii, is also found in chelids and baenids and is assumed to be the primitive condition for pleurodires.</p> <p>Homoplasy: The Podocnemididae acquire the more open fossa meckelii independently of the infrafamily Bothremydodda (Bothremydini + Taphrosphyini).</p> <p>Discussion: This is a synapomorphy for the infrafamily Bothremydodda (Bothremydini + Taphrosphyini). The problem with this character is the few lower jaws known, particularly for the Taphrosphyini.</p> <p>123. Articular, processus retroarticularis: long and projecting posteriorly (Bothremys) 5 0; short or absent (Pelusios) 5 1; long and projecting posteroventrally (Podocnemis) 5 2.</p> <p>Morphology: The lower jaw of bothremydids has a processus retroarticularis that projects straight posteriorly (state 0, fig. 241A). It is not an extremely long processus, as in some cryptodires like trionychids, but it is distinctly longer than in chelids, pelomedusids, and euraxemydids. Unfortunately, it is known for only 7 of 29 taxa of bothremydids. In podocnemidids, Brasilemys, and Hamadachelys, there is also a distinct processus retroarticularis, but it is directed posteroventrally (state 2) and lies below the axis of the jaw ramus (Gaffney, 1979a: fig. 135).</p> <p>Primitive condition: Proganochelys has a long processus retroarticularis (Gaffney, 1990), but cryptodires generally lack one. It is also short or absent in pelomedusids, chelids, and euraxemydids. Although the presence of a processus seems to be primitive for turtles, its absence is primitive for pleurodires.</p> <p>Homoplasy: The short or absent state of this character is present in Pelomedusoides primitively, but it is reversed for bothremydids. The Proganochelys condition is a process with a dorsally open pocket, not seen in bothremydids, supporting the idea that the bothremydid condition is a nonhomologous reversal.</p> <p>This character is in Antunes and Broin (1988), Meylan (1996), and Lapparent de Broin (2000b).</p> <p>124. Vertebrae, cervical ribs: present (Proganochelys) 5 0; absent (Pelusios) 5 1.</p> <p>Morphology: Cervical vertebrae of pleurodires (Williams, 1950; Hoffstetter and Gasc, 1969) lack ribs, even in the Jurassic Platychelys.</p> <p>Primitive condition: The presence of cervical ribs is primitive for turtles as they occur in Proganochelys (Gaffney, 1990) and primitive cryptodires (Gaffney, 1996).</p> <p>Homoplasy: None within pleurodires.</p> <p>125. Vertebrae, cervical postzygapophyses fused: all separate (Proganochelys) 5 0; some fused (Podocnemis) 5 1.</p> <p>Morphology: The postzygapophyses of cervicals in some pleurodires unite to form a combined, single curved surface for the articulation of the prezygapophyses (Meylan, 1996: fig. 9).</p> <p>Primitive condition: Separate postzygapophyses occur in Proganochelys and cryptodires, but within pleurodires the primitive condition is equivocal. The one cervical of Platychelys is unfused, as are all cervicals of Pelomedusidae. Within chelids, fusion is variable but absent in Emydura and Elseya. It is likely that the unfused condition is primitive for Pleurodira.</p> <p>Homoplasy: A problem with this character is the recognition of the form of variability of postzygapophyseal fusion. All cervicals in Araripemys and Euraxemys show fusion, but in chelids and podocnemidids some cervicals in the column are fused and some are not, and this even varies among species. These are all treated as one character, but this may be too simplistic as it lumps a variety of morphologies that may not be homologous. However, to recognize more character states at this point will only make a series of autapomorphies.</p> <p>Discussion: The cervicals of Euraxemys and Araripemys are known, but within Bothremydidae only a few cervicals of Taphrosphys sulcatus, Chedighaii barberi, and Cearachelys are known. Taphrosphys and Chedighaii show fused postzygapophyses, but the two probably posterior cervicals of Cearachelys do not. Because other cervicals of Cearachelys could be fused, it has been coded as ‘‘?’’, but all of the cervicals could lack fused zygapophyses.</p> <p>This character is used in Meylan (1996) and Lapparent de Broin (2000b).</p> <p>126. Vertebrae, cervical postzygapophyses elevated: separated and relatively low (Proganochelys) 5 0; extended posterodorsally on neural spine (Podocnemis) 5 1.</p> <p>Morphology: The neural spine of the cervicals of living pleurodires (Williams, 1950; Hoffstetter and Gasc, 1969) is extended posterodorsally and bears the postzygapophyses. This also occurs in bothremydids, Euraxemys, Araripemys, and Dortoka (Lapparent de Broin and Murelaga, 1999), but it is absent in Notoemys and Platychelys.</p> <p>Primitive condition: The outgroups lack the extended neural spine.</p> <p>Homoplasy: None known.</p> <p>Discussion: Lapparent de Broin and Murelaga (1999) used this character in a dataset and figured a cervical for the skull-less taxon Dortoka. This character helps unite Dortoka with the Eupleurodira.</p> <p>127. Vertebrae, cervical centra: amphicoelous, platycoelous (Proganochelys) 5 0; formed articulation is wider than high (Platychelys) 5 1; formed articulation is higher than wide (Podocnemis) 5 2.</p> <p>Morphology: The wider than high condition (state 1) occurs in Platychelys and Notoemys (Fernandez and Fuente, 1994: fig. 3). It also occurs within Selmacryptodira, but only within Eucryptodira. Unformed articular surfaces are primitive for Selmacryptodira, so the eucryptodiran condition is not reflected in the coding. Although there are few bothremydid cervicals known, they all have cervical centra that are higher than wide (Cearachelys, Chedighaii, Taphrosphys).</p> <p>Primitive condition: Unformed central articulations are in Proganochelys, Palaeochersis, and Cryptodira, and this is the presumed primitive condition.</p> <p>Homoplasy: None in the MPC, but eucryptodires evolve wide centra independent of Platychelys and Notoemys. The higher than wide condition only evolves once, and that is within the Pleurodira.</p> <p>Discussion: State 1 is a synapomorphy for Notoemys + Platychelys. State 2 is a synapomorphy for Dortoka + Eupleurodira.</p> <p>128. Vertebrae, cervical articulation pattern: amphicoelous, platycoelous (Proganochelys) 5 0; (2))3))4))5))6))7))8) (Pelusios) 5 1; (2((3((4((5))6))7((8) (Emydura) 5 2.</p> <p>Morphology: The articulation patterns of procoelous, opithocoelous, biconvex, and biconcave cervical vertebrae developed particularly by Williams (1950) are based on the articulation surface of the cervical centrum. These are described in Vaillant (1881), Kasper (1903), Williams (1950), and Hoffstetter and Gasc (1969), who also provide an introduction to the turtle vertebral literature. The use of parentheses follows that of Williams (1950) and most authors describing vertebrae and symbolizes the shape of the central articulation.</p> <p>Primitive condition: The unformed central surface (Gaffney, 1990, 1996) is primitive for turtles, but Lapparent de Broin and Murelaga (1999) have argued that the chelid condition may be primitive for Pleurodira. According to those authors, Notoemys, Platychelys, and Dortoka all probably have state 2, the chelid articular pattern (see Lapparent de Broin and Murelaga, 1999: 153). This is based on only a few cervicals, but they do show that these taxa do not have the procoelous condition of cervicals 3–8. We have accepted the Lapparent de Broin and Murelaga (1999) hypothesis and coded Platychelys, Notoemys, and Dortoka as state 2, which then becomes the state primitive for Pleurodira, not the unformed (state 0) as used by Gaffney (1996). When the taxa lacking skull data are excluded, this issue becomes moot, as chelids are the only included taxon with the character.</p> <p>Homoplasy: None. Note, however, that a complete vertebral series is as yet unknown for any bothremydid. Cearachelys has three cervicals of unknown position, all procoelous.</p> <p>Discussion: The procoelous condition (state 1) is a synapomorphy for Pelomedusoides in the MPC, with or without shell-only taxa. It is also not affected by coding of Platychelys, Notoemys, and Dortoka with state 2 or with ‘‘?’’.</p> <p>This character is used in Antunes and Broin (1988).</p> <p>129. Vertebrae, caudal articulation pattern: platycoelous, amphicoelous (Proganochelys) 5 0; formed centra but articulations vary, opisthocoelous and procoelous (Notoemys) 5 1; all procoelous (Pelusios) 5 2.</p> <p>Morphology: The central articulations of the caudals of pleurodires are figured in Tronc and Vuillemin (1974: pl. 13, figs. 4–6, Erymnochelys), Gaffney (1990: fig. 130, Podocnemis), Meylan (1996: fig. 2, Araripemys), and Lapparent de Broin and Murelaga (1999: fig. 6, Dortoka).</p> <p>Primitive condition: As with cervicals, the presumed primitive condition is unformed: amphicoelous or platycoelous.</p> <p>Homoplasy: None in the MPC, but the sparse distribution of even partially articulated tails may mask a more complex character distribution. Procoelous caudals, as well as many other patterns, appear with Cryptodira.</p> <p>Discussion: Character state 2 is a synapomorphy for Chelidae + Pelomedusoides (Eupleurodira) and has been known for some time (it was used by Lapparent de Broin and Murelaga, 1999). Character state 1 is also from Lapparent de Broin and Murelaga (1999) and, although ambiguous, it may reflect a pattern of diverse central articulations that are at least not all procoelous. Nonetheless, this is a weak character state, known only from disarticulated caudals in Dortoka (Lapparent de Broin and Murelaga, 1999) and two from Platychelys (Bräm, 1965) that show opisthocoely as well as procoely.</p> <p>130. Shoulder girdle, coracoid foramen: present (Proganochelys) 5 0; absent (Podocnemis) 5 1.</p> <p>See Gaffney (1990) for description; also see Rougier et al. (1995).</p> <p>131. Shoulder girdle, coracoid shape: coracoid a flat plate (Proganochelys) 5 0; coracoid columnar (Podocnemis) 5 1.</p> <p>See Gaffney (1990) for description; also see Rougier et al. (1995).</p> <p>132. Pelvic girdle, tenth thoracic centrum: not incorporated into sacrum (Proganochelys) 5 0; incorporated into sacrum (Pelusios) 5 1.</p> <p>Morphology: Broin and Murelaga (1999: pl. 12, fig. 5: Peltocephalus) figured the sacrum, showing this character, but this area is not well described in the literature (see also Fraas, 1913: Proterochersis; Tronc and Vuillemin, 1974: Erymnochelys; and Fernandez and Fuente, 1994: Notoemys). The presence of the tenth thoracic rib in the sacrum can be determined by the suturing of the distal end to the ilium. The ilium itself is also sutured to the carapace.</p> <p>Primitive condition: In Proganochelys (Gaffney, 1990) the tenth thoracic rib is fused to the ninth costal, and this is presumably the primitive condition. In cryptodires, the tenth rib is usually free.</p> <p>Homoplasy: None known, but the character is not known in most bothremydids and in many other extinct pleurodires.</p> <p>Discussion: This character is a synapomorphy for Pleurodira and is presumably related to the sutured pelvis-carapace.</p> <p>133. Pelvic girdle, pelvis sutured to shell: pelvis articulates only by ligaments, no sutures (Proganochelys) 5 0; all three bones of pelvis sutured to shell (Pelusios) 5 1.</p> <p>Morphology: This character is figured in Rütimeyer (1873: pl. 8), Bräm (1965: pl. 1), Gaffney (1990: figs. 143, 144 for the pelvis alone of Podocnemis), and Lapparent de Broin and Murelaga (1999: pl. 12). Considering how widely used this character is for Pleurodira, it is not well described in the literature.</p> <p>Primitive condition: The outgroups Proganochelys and Cryptodira have a free pelvis, which is the primitive condition (Gaffney, 1990). Rougier et al. (1995) described Palaeochersis as having a sutured pelvis. Examination of this material by the senior author shows that the pelvis in Palaeochersis is not sutured to the carapace or plastron, but rather it has been crushed dorsoventrally to produce a condition that can be mistaken for suturing. The pelvis and adjacent shell surfaces show no signs of sutures, rather they are very similar to the morphology in Proganochelys.</p> <p>Homoplasy: None known.</p> <p>Discussion: This is a long-used synapomorphy for Pleurodira.</p> <p>Lapparent de Broin and Murelaga (1999: 150) added a second state, ‘‘ligamentous more firmly linked producing a true articulation scar’’, and coded it for Proterochersis in their dataset. Extensive study of the known material of Proterochersis by two of the authors (E.S.G. and P.A.M.) shows no difference in the type of attachment between pelvis and shell in Proterochersis and all other pleurodires, so we reject this second character state.</p> <p>134. Pelvic girdle, dorsal part of ilium columnar: no, inclined with anterior and posterior processes (Proganochelys) 5 0; columnar, expanded mediolaterally (Podocnemis) 5 1.</p> <p>Morphology: In pleurodires the ilium is a relatively thick columnar element, not flattened with anterior and/or posterior processes as in Proganochelys and cryptodires (Gaffney, 1990: figs. 143, 144. It is also oriented more vertically in pleurodires than in other turtles.</p> <p>Primitive condition: In Proganochelys the ilium is expanded anteriorly and posteriorly, forming a horizontally oriented, inclined structure. Cryptodires have a wide diversity of ilium shapes, but primitively they have an inclined, mediolaterally flattened shape, similar to Proganochelys.</p> <p>Homoplasy: None known.</p> <p>Discussion: This character attempts to reflect further information from the pelvic morphology of pleurodires. Perhaps it is correlated with the suturing of the pelvis to the shell.</p> <p>135. Pelvic girdle, pelvis narrow: ilia and acetabula relatively far from midline (Proganochelys) 5 0; ilia and acetabula close to midline (Podocnemis) 5 1.</p> <p>Morphology: Although this character is somewhat subjective, all pleurodires do have the ilial column and acetabulum closer to each other and to the midline than in other turtles (i.e., Proganochelys and cryptodires), producing a narrower pelvis. Presumably this is related to the sutured pelvis-shell. Gaffney (1990: fig 144) compared Proganochelys, a cryptodire, and a pleurodire pelvis, showing this condition.</p> <p>Primitive condition: The wide pelvis of Proganochelys and cryptodires is primitive.</p> <p>Homoplasy: None known; however, a complete pelvis is not preserved for most bothremydids and many other extinct taxa.</p> <p>Discussion: This character is used by Lapparent de Broin and Murelaga (1999), it is another pleurodire synapomorphy.</p> <p>136. Pelvic girdle, thyroid fenestra: separate (Proganochelys) 5 0; confluent (Podocnemis) 5 1.</p> <p>Morphology: The thyroid fenestrae of Proganochelys, a pleurodire, and a cryptodire are figured in Gaffney (1990: fig. 144). In the advanced state the fenestra is not subdivided down the center by bone.</p> <p>Lapparent de Broin and Murelaga (1999) divided this character in a series of states based on the fenestra size. Proterochersis has slightly larger fenestrae than does Proganochelys, but they are still relatively small and widely separated by bone. Rather than calling this a separate state, we identify both as primitive. Platychelys has fenestrae that are not separated by bone but are somewhat smaller than those in Eupleurodira. Rather than making this a separate state, we identify it as the advanced condition because the fenestrae are confluent.</p> <p>Primitive condition: The small, widely separated fenestrae of Proganochelys are primitive.</p> <p>Homoplasy: It is likely that the confluent thyroid fenestrae arose separately in cryptodires and pleurodires.</p> <p>Discussion: This character is used in Rougier et al. (1995) and Lapparent de Broin and Murelaga (1999).</p> <p>137. Humerus, shoulder on lateral side of head: present (Proganochelys) 5 0; absent (Podocnemis) 5 1.</p> <p>Morphology: The humerus of pleurodires has a head that is hemispherical and slightly separated from the lateral and medial processes (Zangerl, 1948: fig. 13, Chedighaii; Gaffney, 1975a: fig. 12, Taphrosphys; Gaffney, 1990: fig. 149, Podocnemis; Fernandez and de la Fuente, 1994: fig. 6, Notoemys). The curved shoulder found on the lateral side of the articular head in Proganochelys and cryptodires is absent in pleurodires.</p> <p>Primitive condition: Proganochelys has a shoulder and an articular head that is not as spherical as in pleurodires. This is presumed to be primitive.</p> <p>Homoplasy: None in the MPC; however, this character gets harder to identify when looking within various eucryptodire groups. Also, the humerus is not known for many bothremydids and other extinct pleurodires.</p> <p>Discussion: This is a pleurodire synapomorphy. Proterochersis lacks a humerus, however.</p> <p>138. Carapace, cervical scale: present (Emydura) 5 0; absent (Podocnemis) 5 1.</p> <p>Morphology: The cervical or nuchal scale is an unpaired scale on the anterior margin of the nuchal bone of most turtles. Except in Hydromedusa (see Wood and Moody, 1976), it lies between the first marginal scales. It is absent in Pelomedusoides (fig. 265).</p> <p>Primitive condition: A cervical scale is present in Proganochelys (Gaffney, 1990), in primitive cryptodires (Gaffney, 1979b), in the primitive pleurodires Proterochersis, Platychelys, and Notoemys (Fernandez and de la Fuente, 1994), and in nearly all chelids. Presence of this scale is clearly the primitive condition.</p> <p>Homoplasy: Loss of the cervical scale occurs independently within the Pleurodira (all members of the Pelomedusoides and one chelid, Elseya, fide Pritchard and Trebbau, 1984) and Cryptodira (some testudinids). It is variable within Dortoka (Lapparent de Broin and Murelaga, 1999).</p> <p>Discussion: The absence of a cervical scale is a synapomorphy for the Pelomedusoides.</p> <p>This character was used by Antunes and Broin (1988), Broin (1988), Gaffney (1988), Gaffney and Meylan (1988), Meylan (1996), Tong et al. (1998), and Lapparent de Broin and Murelaga (1999).</p> <p>139. Carapace, nuchal bone width: nuchal bone two or more times wider than length (Platychelys) 5 0; nuchal bone width greater than length but less than two times (Euraxemys) 5 1; nuchal bone width approximately equals length (Foxemys) 5 2; nuchal width less than length (Teneremys) 5 3; nuchal bone greatly emarginated (unique to Araripemys) 5 4.</p> <p>Morphology: The width versus length of the nuchal bone in dorsal view (figs. 254– 274) is arbitrarily subdivided into four states. This character is used in Lapparent de Broin and Murelaga (1999); we have slightly modified it. Araripemys (Meylan, 1996) has a uniquely emarginated nuchal, making it hard to compare with other turtles, so it is given state 4, unique to that taxon.</p> <p>Primitive condition: Both Proganochelys and primitive cryptodires have a very wide (state 0) nuchal, and this occurs in Platychelys and Notoemys, but the character is indeterminate in Palaeochersis and Proterochersis.</p> <p>Homoplasy: Quite a lot, within Selmacryptodira, Chelidae, Pelomedusidae, and Podocnemididae, but for this analysis the CI is 0.66. Nuchal width is often variable within a species. Nonetheless, some patterns are apparent in the MPC.</p> <p>Discussion: The change from state 0 to state 1 is a synapomorphy for Dortoka + Eupleurodira, the parvorder Megapleurodira, and state 1 is primitive for nearly all groups in Eupleurodira. State 3 is unique to Teneremys and state 4 is unique to Araripemys. Foxemys and Polysternon are united by state 2.</p> <p>This character is used in Lapparent de Broin (2000b), who agreed that the wide condition is primitive.</p> <p>140. Carapace, pygal notch: present, wide and shallow (Proganochelys) 5 0; present, narrow and spherical (unique to Proterochersis) 5 1; absent, margin smooth (Podocnemis) 5 2.</p> <p>Morphology: The pygal notch in Proganochelys is figured in Gaffney (1990: figs. 69– 77) and in Palaeochersis by Rougier et al. (1995). The pygal notch of Proterochersis has not been figured. The absent condition can be seen in nearly all other turtles.</p> <p>Primitive condition: Presumably, the presence of a pygal notch is primitive for turtles.</p> <p>Homoplasy: None, although some cryptodires acquire an emarginated posterior carapace margin.</p> <p>Discussion: The posterior carapace emargination or pygal notch in Proterochersis is so different from that in Proganochelys that a separate state is identified for it. In this we follow Lapparent de Broin and Murelaga (1999) who also used two states for the pygal notch. Rougier et al. (1995) used ‘‘marginals not separated by an anal notch’’, but we think that this obscures a more complex situation.</p> <p>141. Carapace, neural series completeness: neurals reach suprapygal (Euraxemys) 5 0; to eighth costals (Podocnemis) 5 1; to seventh costals (Foxemys) 5 2; to sixth costals (Chedighaii) 5 3; neurals absent or discontinuous (Araiochelys, Emydura) 5 4.</p> <p>Morphology: The neural bones of the carapace usually make up the midline of the shell between the nuchal and suprapygal. In most turtles they form a continuous series between the nuchal and suprapygal; in others, some or all costals meet on the midline. In some forms neurals are completely absent. The neurals reaching the suprapygal and forming a complete series is state 0 (fig. 254), reaching to the eighth costals is state 1 (fig. 272), reaching to the seventh costals is state 2 (fig. 259), reaching to the sixth costals is state 3 (fig. 264), and discontinuous or absent neurals is state 4 (fig. 263).</p> <p>Primitive condition: The neural series of Proganochelys is not completely known. However, the neural series in such primitive cryptodires as Kayentachelys and Pleurosternon is complete (state 0), as are those of Platychelys (Bräm, 1965) and Notoemys (Fernandez and de la Fuente, 1994). The neural series is complete among Pelomedusoides in Euraxemys, Cearachelys, and some Araripemys.</p> <p>Homoplasy: Interruption of a complete neural series by costals meeting on the midline occurs within Podocnemididae and Bothremydidae. Among the Cryptodira, trionychids, kinosternids, and dermatemydids all have posterior costals meeting on the midline. Cearachelys is apparently a reversal in which the complete neural series is reacquired. The pelomedusids independently lose a full neural series. The CI is 0.42.</p> <p>Discussion: State 1 is a synapomorphy for the epifamily Podocnemidinura, and state 2 has equivocal support for Bothremydidae, except for Cearachelys, which has a complete set of neurals.</p> <p>A variant of this character is used in Antunes and Broin (1988), Meylan (1996), Tong et al. (1998), Lapparent de Broin and Murelaga (1999), and Lapparent de Broin (2000b).</p> <p>142. Carapace, iliac scar position: iliac scar absent (Chelydra) 5 0; iliac scar restricted to costals 7 and 8 (Pelusios) 5 1; iliac scar on costals 7, 8, and suprapygal (Taphrosphys) 5 2.</p> <p>Morphology: The ilium of pleurodires articulates with the bones of the carapace in a sutural contact. The elements with which the ilium articulates vary among species in the suborder (Lapparent de Broin and Murelaga, 1999: pl. 12). In some the articulation is only with costals 7 and 8, and in others the suprapygal and or peripheral elements are also involved. For example, in Notoemys the ilium articulates with the eighth costals and suprapygal, while in Platychelys it articulates with the eighth costals, suprapygal, and eleventh peripherals (Fernandez and de la Fuente, 1994). State 1 is the scar on costals 7 and 8 (Lapparent de Broin and Murelaga, 1999: pl. 12, fig. 5), and state 2 is the scar on costals 7, 8, and the suprapygal (fig. 265).</p> <p>Primitive condition: For turtles, the absence of a scar is primitive; the two states are derived. Contact of the ilium in Platychelys includes the eighth costals, suprapygal, and eleventh peripherals (Fernandez and Fuente, 1994). In Araripemys, the ilium contacts the seventh and eighth costals and the suprapygal. Thus, it appears that contact to the suprapygal may be primitive for pleurodires. Antunes and Broin (1988) argued that the inclusion of the suprapygal in this contact in bothremydids is a reversal to the primitive condition. However, Lapparent de Broin (2000b: 45) considered suprapygal contact primitive for Pelomedusoides. We are uncertain of the evidence that contact to the suprapygal is lost and regained.</p> <p>Homoplasy: There is individual variation in this contact within the specimens of Chedighaii barberi figured by Zangerl (1948, one figure shows suprapygal contact and one does not) and within recent specimens of Podocnemis expansa and P. unifilis seen by the senior author.</p> <p>Discussion: Lapparent de Broin and Werner (1998) indicated that broad contact with costal 8 and narrow contact with neural 7 and the suprapygal are the general condition for bothremydids. However, contact in Kurmademys is on costals 7 and 8 only (ISIR 278), so the issue is still ambiguous. The area is known in only a few bothremydids.</p> <p>A related character is used in Lapparent de Broin and Murelaga (1999), which reflects the scar shape. It is also used in Antunes and Broin (1988) and Lapparent de Broin (2000b).</p> <p>143. Carapace, first costal length: costal 1 shorter or equal to twice the length of costal 2 (Euraxemys) 5 0; costal 1 more than twice the length of costal 2 (Foxemys) 5 1.</p> <p>Morphology: The elements of the anterior portion of the shell of turtles include a first costal bone that is longer anteroposteriorly than the more posterior costals (state 1, fig. 259). In the most primitive turtles, the first costal is not longer than more posterior costals. However, in many forms the first costal is anteroposteriorly long, often two or more times longer than the second costal. This is a gradational character that is arbitrarily defined as the condition where the anteroposterior length of costal 1 is more than twice that of the second costal. This identifies the more extreme end of a gradational character and may be slightly more objective than dividing the character into more states.</p> <p>Primitive condition: In Proganochelys and Platychelys the first costal is approximately as long as those of the more posterior costals. This is the best evidence for the primitive condition of this character in pleurodires.</p> <p>Homplasy: The first costal is anteroposteriorly longer than the more posterior costals in most turtles. However, first costals that are more than twice as long as the second are not common, but they do occur in Dortoka, Kurmademys, Bothremydini, Taphrosphyini, Podocnemis, and some chelids. In the MPC, the CI is 0.33 and the character arises three times.</p> <p>Discussion: In the MPC, this character is synapomorphic for the infrafamily Bothremydodda (consisting of the tribes Bothremydini and Taphrosphyini), but its rather subjective nature is a problem.</p> <p>144. Carapace, position of four-sided neural: neural 1 (Euraxemys) 5 0; neural 2 (Cearachelys) 5 1; neural 3 (Araripemys) 5 2; four-sided neural absent (Platemys) 5 3.</p> <p>Morphology: Characterizing the neural morphology is a very dubious business. Multiple attempts have been made to characterize neural bone morphology, and none has been satisfactory. One way is to count the sides contacting surrounding elements, considering each contact a side (Auffenberg, 1974). This produces a formula running from anterior to posterior, as in Euraxemys: 4-6-6- 6-6-6-6-6. In this case the four-sided or quadrangular neural is first (state 0, fig. 265). The four-sided neural may be the second, as in Cearachelys: 6-4-6-6-6-6-6-4 (state 1, fig. 258), or it may be the third neural, as in Araripemys: 6-6-4-6-6-6-6-4 (state 2; Meylan, 1996: fig. 1). In most Pleurodira, the posterior neurals are all six-sided, but the position of the reversed or four-sided neural varies. In some cases, including some pleurodires, reversal in neural orientation occurs via two consecutive five-sided neurals, as in Brasilemys (Lapparent de Broin, 2000b: fig. 4).</p> <p>Primitive condition: Only neurals 4–7 are known for Proganochelys, and these all seem to be six-sided. Meylan and Gaffney (1989) have argued that the primitive condition for Casichelydia is 4-6-6-6-6-6-6, and this is what we have chosen for state 0. However, Kayentachelys (Gaffney et al., 1987) has the second neural four-sided (although there is individual variation), Platychelys and Notoemys have the second and fourth neurals four-sided, and Proterochersis is unknown, so the primitive neural pattern is still unclear.</p> <p>Homoplasy: In the MPC, the four-sided first neural is primitive and pervasive throughout the pleurodires, with the other conditions mostly appearing independently, with a CI of 0.75. The neural 2 four-sided condition does unite Cearachelys with the two possible Galianemys shells, AMNH 30550 and AMNH 30551. In any case, these characters occur widely as individual variation among many species of turtles, and they can be highly variable within species in some families (Auffenberg, 1976; Meylan, 1984, 1987).</p> <p>Discussion: Lapparent de Broin and Murelaga (1999) used a variation of this character in their dataset. Lapparent de Broin (2000b: 45) implied that state 1 may be primitive for Pelomedusoides. In the MPC analyzed here, state 1 is synapomorphic for Cearachelyini (supporting the AMNH 30550 and AMNH 30551 shells as belonging to Galianemys) and, independently, for Notoemys + Platychelys.</p> <p>145. Carapace, neural series pattern: irregular, neurals 2 and 4 quadrangular, alternating in width (Platychelys) 5 0; irregular, width even (Kayentachelys) 5 1; regular, most hexagonal, coffin-shaped (Podocnemis) 5 2; neurals absent (Platemys) 5 3; neurals discontinuous (Araiochelys) 5 4.</p> <p>Morphology: This is another feeble attempt to use neural diversity as a character. Lapparent de Broin and Murelaga (1999) and Fuente and Iturralde-Vinent (2001) used ‘‘regular’’ versus ‘‘irregular’’ to distinguish the common casichelydian pattern of one quadrangular neural (in the anterior part of the series) followed by hexagonal, coffin-shaped neurals, from the ‘‘irregular’’ neural pattern of alternating contacts and widths. Lapparent de Broin and Murelaga (1999) used the ‘‘irregular’’ as one state, but this is a diverse group, and we have subdivided it. The taxa placed in this group by Lapparent de Broin and Murelaga (1999) all have more than two quadrangular neurals in common, but the position and width of these neurals vary. They also have a high occurrence of asymmetry, with many five- and seven-sided neurals. Kayentachelys has the neural width the same for the series (state 1, Gaffney et al., 1987), while Notoemys (Fernandez and Fuente, 1994) and Platychelys (Lapparent de Broin, 2001) have an alternating width pattern (state 0). Dortoka (Lapparent de Broin and Murelaga, 1999), irregular but somewhat unique, is also coded as state 0. The common pattern, state 2, is seen in the Eupleurodira (fig. 265). Araiochelys has the discontinuous condition, state 4 (fig. 263).</p> <p>Primitive condition: The primitive condition would be ‘‘irregular’’ as one state, but as we have subdivided them, there is no clear primitive pattern. We have arbitrarily chosen the Platychelys condition as ‘‘0’’. Note that the neurals known for Proganochelys (4–7) do show the ‘‘regular’’, coffin-shaped pattern, so state 2 could be argued as primitive. Because many neurals are missing in Proganochelys, it is coded as ‘‘?’’.</p> <p>Homoplasy: The ‘‘regular’’, state 2 condition has evolved at least once within pleurodires and at least once within cryptodires.</p> <p>Discussion: This character is from Lapparent de Broin and Murelaga (1999), but they basically recognized only two states outside of chelids. We have recognized more states in the ‘‘irregular’’ condition, because the absence of ‘‘regular’’ includes a series of states that are not the same. It is difficult to specifically define patterns in common because bilateral asymmetry is common among the early pleurodire shells. Nonetheless, the ‘‘regular’’ pattern (state 2) does support a group, the Eupleurodira.</p> <p>146. Carapace, neural number: more than eight (Kayentachelys) 5 0; eight (Cearachelys) 5 1; seven (Foxemys) 5 2; six or fewer (Kurmademys) 5 3.</p> <p>Morphology: The neural bones are easily counted, but some may not be fused to the underlying vertebral spines and might not be considered separate neurals (e.g., the posterior neurals of Kayentachelys and Platychelys, but this can also occur as an individual variation throughout chelonians). This is the argument for making this a separate character from character 141 (see below).</p> <p>Primitive condition: This is difficult to assess because Proganochelys and Palaeochersis lack complete series. We have chosen the ‘‘more than eight’’ as primitive because of its occurrence in outgroups such as Kayentachelys and Platychelys.</p> <p>Homoplasy: Even though the CI is 0.42, homoplasy is extensive for these character states due to variation within chelids, pelomedusids, cryptodires, Platychelys, and Araripemys. The loss of neurals within Bothremydidae could be more widespread than shown in the MPC, because the generically indeterminate shells from Tunisia (e.g., ‘‘ Eusarkia ’’, ‘‘ Gafsachelys ’’) show neural loss, and some of them seem to be Taphrosphyini.</p> <p>Discussion: This is very similar to character 141, which might be considered just another way of counting neurals. Deleting either results in the same MPC, but deleting them does affect the placement of the poorly known shell-only taxa.</p> <p>Although this is a widely variable character, the MPC shows that seven neurals (state 2) is a synapomorphy for podocnemidids + bothremydids + Teneremys. Similarly, despite independent acquisition in cryptodires and elsewhere, eight neurals (state 1) is a synapomorphy for pleurodires, with Proterochersis unknown.</p> <p>A version of this character appears in Lapparent de Broin and Murelaga (1999).</p> <p>147. Carapace, length of contact between peripheral 1 and costal 1 in dorsal view: no contact due to large nuchal (Dortoka) 5 0; wide contact so that anterior margin of peripheral 1 is less than twice the length of costal 1 contact (Rosasia) 5 1; narrow contact, so that anterior margin of peripheral 1 is twice or more the length of costal 1 contact (Foxemys) 5 2; no contact due to small nuchal (unique to Araripemys)5 3.</p> <p>Morphology: This character is a modification of one used by Lapparent de Broin and Murelaga (1999). Their character states are: ‘‘wide contact (0), wide contact or no contact (1), wide or narrow contact (2)’’ (Lapparent de Broin and Murelaga, 1999: 150). Apart from their not inconsiderable entertainment value, the state characterizations are useless. In an effort to squeeze something objective out of this mess, we have arbitrarily divided a fairly continuous character into wide (state 1, fig. 261) and narrow (state 2, fig. 259) by comparing the relative width of the anterior and posterior margins.</p> <p>Primitive state: The character is not known for Proganochelys, Australochelys, Palaeochersis, and Proterochersis, and there is no obvious distribution pattern in the MPC for a primitive condition for turtles. The state 0 was chosen arbitrarily.</p> <p>Homoplasy: Lots. The width of the contact between the first peripheral and the first costal is highly variable in turtles. However, the condition in Dortoka with anterolateral notches in the nuchal for the first peripherals seems to be autapomorphic. Although the CI is merely 0.33 due to rampant equivocality, state 2 appears six times independently in the MPC, and state 1 appears seven times.</p> <p>Discussion: The narrow contact could be a synapomorphy for eupleurodires, although it is variable in pelomedusids (and probably in chelids, if enough shells are examined). The first peripheral shape could be characterized in other ways, comparing margin length with costal length, for example, but there does not seem to be any advantage in doing this.</p> <p>This character is from Lapparent de Broin and Murelaga (1999) and, even as modified, we use it with reservations, but it reflects our effort to include as much of Lapparent de Broin’s work on shells as possible.</p> <p>148. Carapace, axillary process contacts first costal: no contact (Proganochelys) 5 0; contact present, separated from posterior margin, may be placed in middle of costal (Chedighaii) 5 1; contact present, placed on posterior border close to second costal (Dortoka) 5 2.</p> <p>Morphology: The dorsal process of the hyoplastron may contact the first costal and form a sutural surface. Lapparent de Broin and Murelaga (1999) used this character as two states, and we follow that here. State 1 is a contact area that is often curved and lies in the middle of the costal or at least separated from the posterior edge (Zangerl, 1948: fig. 7, Chedighaii). In state 2 (Lapparent de Broin and Murelaga, 1999: pl. 3, fig. 12a), the axillary buttress lies on the posterior edge of costal 1, very close to the contact with costal 2.</p> <p>Primitive condition: Proganochelys and Kayentachelys have no axillary buttress contact on the first costal, and this is presumably the primitive state.</p> <p>Homoplasy: This character has reversals within chelids, pelomedusids, and podocnemidids, as well as within Taphrosphys sulcatus. Probably a more extensive study of recent pleurodire shells would show more withinspecies variation, although the CI is 0.5.</p> <p>Discussion: Although the character shows a fair amount of homoplasy at the generic and specific levels, state 1 is synapomorphic for the Bothremydidae and state 2 pulls together Dortoka and eupleurodires.</p> <p>Lapparent de Broin and Werner (1998) have an extensive discussion of the axillary buttress meeting the carapace in pleurodires. Unfortunately, most of the literature on pleurodire shells lacks figures and detailed morphology on the internal shell morphology, such as buttress attachments, limiting the value of this and other internal shell characters.</p> <p>149. Carapace, axillary process extent on ventral surface of peripherals: reaches peripheral 2 (Platychelys) 5 0; reaches anterior margin of peripheral 3 (Emydura) 5 1; reaches onto main body or posterior edge of peripheral 3 or is restricted to peripheral 4 (Chedighaii) 5 2.</p> <p>Morphology: The axillary process of the hyoplastron can extend anteriorly onto the peripherals, as well as medially, onto the first costal. The character states are continuous but can be divided because it is easy to see the sutural area separated by interperipheral sutures. State 0, the buttress reaching the second peripheral, can be seen in Proganochelys (Gaffney, 1990: fig. 102). In state 1 the buttress reaches nearly to the peripheral 2–peripheral 3 contact, which can be seen in some chelids and some podocnemidids (Tronc and Vuillemin, 1974: pl. 13, fig 1). In state 2 the buttress reaches the main body of peripheral 3 (Zangerl, 1948: fig. 4).</p> <p>Primitive condition: The anterior extension of the axillary buttress to peripheral 2 is found in Proganochelys, and it seems to be primitive for turtles.</p> <p>Homoplasy: Except for homoplasy within chelids and podocnemidids, and a reversal in MNHN GDF 801, this character shows no reversals or homoplasy within pleurodires.</p> <p>Discussion: The state 2 condition, restriction of the axillary contact to the middle or posterior part of peripheral 3, is a synapomorphy for Dortoka + Eupleurodira.</p> <p>This character is used by Lapparent de Broin and Werner (1998) and Lapparent de Broin and Murelaga (1999).</p> <p>150. Carapace, inguinal buttress: short or absent, not making extensive contact with costal 5 (Proganochelys) 5 0; inguinal buttress of hypoplastron contacts costal 5, extending medially onto it (Chedighaii) 5 1.</p> <p>Morphology: This character is best seen in a ventral view of the fifth costal, which shows the articulation surface. When the plastron is present, the contact area is usually obscured. Proganochelys shows state 0 (Gaffney, 1990: fig. 76) and Lapparent de Broin and Murelaga (1999) show state 1 for Dortoka (Lapparent de Broin and Murelaga, 1999: fig. 1) and Polysternon (Lapparent de Broin and Murelaga, 1999: pl. 5).</p> <p>Primitive condition: Proganochelys has no inguinal buttress contact (state 0).</p> <p>Homoplasy: State 1 has evolved at least three times in the MPC and is variable within the Pelomedusidae and the Podocnemididae.</p> <p>Discussion: This character supports uniting Teneremys and the Podocnemidoidea. This character is used by Lapparent de Broin and Murelaga (1999) and Fuente and Iturralde-Vinent (2001).</p> <p>151. Carapace, supramarginal scales: 12 or more pairs (Proganochelys) 5 0; 3 pairs (Proterochersis) 5 1; absent (Podocnemis) 5 2.</p> <p>Morphology: Supramarginal scales showing states 0 and 1 are figured in Gaffney (1990: fig. 105). Their absence, state 2, can be seen in figure 264.</p> <p>Primitive condition: Proganochelys and Palaeochersis have 12 or more supramarginals.</p> <p>Homoplasy: The most parsimonious explanation for the distribution of this character in the MPC requires the reappearance of supramarginals in Platychelys and Proterochersis. The absence of supramarginals in nearly all cryptodires requires that state 1, three pairs of supramarginals in the earliest pleurodires, evolve from state 2, no supramarginals. Although this seems unlikely, it is apparently the case in Macrochelys (P.A.M., personal obs.), and the loss of supramarginals in cryptodires and pleurodires independently, the more likely hypothesis as far as supramarginals are concerned, is not supported by the MPC.</p> <p>Discussion: Total loss of supramarginals, state 2, is a synapomorphy for Casichelydia in the MPC. State 1, three supramarginals, evolves twice (or is lost once) within that group. As discussed above, the reappearance of supramarginals seems unlikely, and it is only one step away from the independent loss of them within pleurodires and in cryptodires.</p> <p>This character was used for Eupleurodira by Gaffney and Meylan (1988) and in datasets by Lapparent de Broin and Murelga (1999) and Fuente and Iturralde-Vinent (2001).</p> <p>152. Carapace, vertebral scale width: equal to or wider than pleural scales (Proterochersis) 5 0; narrower than pleural scales (Foxemys) 5 1.</p> <p>Morphology: State 0, wide vertebrals, is figured in Gaffney (1990: fig. 105); narrow vertebrals, state 1, is figured in figure 264. The wide vertebrals of Proterochersis, Platychelys, and Notoemys are distinct from Dortoka and Eupleurodira, with their narrow ones.</p> <p>Primitive condition: Proganochelys has wide vertebrals, state 0.</p> <p>Homoplasy: Narrow vertebrals have evolved twice, once within Selmacryptodira and once within Pleurodira.</p> <p>Discussion: Some specimens of Platychelys seem to have vertebral scales that are about as wide as some of the pleural scales, but others have wider vertebrals.</p> <p>This character is a synapomorphy for Dortoka + Eupleurodira.</p> <p>153. Carapace, vertebral scale 1 reaches anterior margin of shell: no, first marginal scales meet on midline (Podocnemis), or cervical scale is present (chelids) 5 0; yes (Araripemys) 5 1.</p> <p>Morphology: In most turtles the first marginal scales and the cervical scale or marginal scales alone (Pelomedusoides) intervene between the first vertebral scale and the shell margin. In MNHN GDF 801 (‘‘ Platycheloides cf. nyasae ’’ of Broin, 1980: pl. 1) and Araripemys, the first marginal scales do not meet on the midline, and the first vertebral reaches the anterior shell margin (Meylan, 1996: fig. 1).</p> <p>Primitive condition: First marginal scales meeting medially occurs in all Pelomedusoides outgroups.</p> <p>Homoplasy: The character occurs twice, independently, in the MPC.</p> <p>Discussion: This character does not form groups in the MPC, more evidence of staunch objectivity. Or poor judgment.</p> <p>154. Carapace, nuchal embayment: absent (Emydura) 5 0; present (Chedighaii) 5 1.</p> <p>Morphology: The anterior margin of the nuchal bone is curved, concave anteriorly, and centered on the midline in this character (fig. 264). When the margin is straight or convex anteriorly, the character is absent (fig. 265). A slight groove where the sulcus separates the first two marginals is not an embayed nuchal.</p> <p>Primitive condition: Although the anterior margin of the nuchal is recessed from the peripherals in Proganochelys, and does not look like the condition in bothremydids, we have coded it as embayed. Kayentachelys also has a concave edge to the nuchal, but it has a different shape from the incised V-shape of Chedighaii.</p> <p>Homoplasy: The embayed condition seems to have arisen at least six times, as reflected in the low CI of 0.2.</p> <p>Discussion: The embayed nuchal occurs in three of the five Bothremydini species in which it is known, so it might be interpreted as a tribe Bothremydini synapomorphy. It supports uniting Teneremys and MNHN GDF 801.</p> <p>This character is in Antunes and Broin (1988).</p> <p>155. Carapace, first thoracic rib: large (close to size of first costal rib) and separated form first costal rib (Platychelys) 5 0; small (smaller than first costal rib) and closely attached to first costal rib (Podocnemis) 5 1.</p> <p>Morphology: State 0 is clear in Proganochelys (Gaffney, 1990: figs. 76, 77) in which the first thoracic rib is as large as the first costal (5 second thoracic) rib and is widely separated from it. Proterochersis, Notoemys, and Platychelys have smaller first thoracic ribs that are closer to the first costal rib than in Proganochelys, but they are not as small or as close as in other pleurodires. Furthermore, the degree of proximity of the two ribs and the relative size of thoracic rib 1 vary among Proterochersis, Platychelys, and Notoemys. Lapparent de Broin and Murelaga (1999) and Fuente and Iturralde-Vinent (2001) used four character states to reflect these differences. However, this only produces unique, autapomorphic character states for Platychelys and Notoemys, losing some potential information. We take a more inclusive view of first thoracic rib size and only use two states. State 1 is figured in Tronc and Vuillemin (1974: pl. 13, fig 1).</p> <p>Each rib that is associated with a thoracic vertebra can be identified by the number of that vertebra. After the first thoracic rib, each rib is also fused distally to a costal bone and can be identified as a costal rib of a particular number. Because the first thoracic rib has no associated costal bone, the numbering of the following ribs is offset so that thoracic rib 2 is also costal rib 1, thoracic rib 3 is costal rib 2, and so on. There is no preferred identification of the rib heads as to thoracic or costal.</p> <p>Primitive condition: Proganochelys shows the primitive state.</p> <p>Homoplasy: None known, but Notoemys and Platychelys may be considered equivocal because the character is gradational.</p> <p>Discussion: The eupleurodires + Dortoka have state 1; Notoemys may also have this state, however.</p> <p>This character is used in Gaffney et al. (1991), Lapparent de Broin and Murelaga (1999), and Fuente and Iturralde-Vinent (2001).</p> <p>156. Carapace, costovertebral tunnel: wide anteriorly and posteriorly only (Proganochelys) 5 0; wide for entire length (Platychelys) 5 1; narrow for entire length (Chedighaii) 5 2.</p> <p>Morphology: The costovertebral tunnel is the space formed between the free part of the thoracic rib and the overlying costal bone; the thoracic centrum defines it medially. State 0 is figured in Gaffney (1990: fig. 78), and state 1 is figured in Bräm (1965: pl. 1, fig. 5).</p> <p>Primitive condition: The Proganochelys condition, state 0, is unique to that taxon at present, so the primitive condition is ambiguous.</p> <p>Homoplasy: The entire length being wide occurs only in Platychelys and Notoemys, although Chelus and some emydids approach this condition.</p> <p>Discussion: The conditions of the costovertebral tunnel are not identical in Proganochelys and Proterochersis. Proterochersis has a wide tunnel, not reduced along costals 2–6 as in Proganochelys, but not as wide as in Notoemys and Platychelys.</p> <p>This character is used in Lapparent de Broin and Murelaga (1999) and Fuente and Iturralde-Vinent (2001).</p> <p>157. Carapace, articulation facet on thoracic rib 1: absent, anterior edge smooth (Proganochelys) 5 0; swollen facet or tubercle on anterior margin of first thoracic rib (Platychelys) 5 1.</p> <p>Morphology: On the medial end of the first thoracic rib, there is a swollen tubercle that looks like an articulation facet (Bräm, 1965: pl. 1, fig. 5). This occurs only in Platychelys and Notoemys. Although it is close to the centrum articulation, it does not seem to be for a cervical articulation. It is probably an articulation site for the dorsal process of the scapula.</p> <p>Primitive condition: The absence of a facet, as in Proganochelys, is primitive.</p> <p>Homoplasy: None.</p> <p>Discussion: This character is a synapomorphy for Notoemys + Platychelys.</p> <p>158. Plastron, mesoplastra: present and meet on midline (Proganochelys) 5 0; present, wider than long (Platychelys) 5 1; present, roughly equidimensional (Chedighaii) 5 2; absent (Emydura) 5 3.</p> <p>Morphology: The medially meeting mesoplastra, state 0, are figured in Gaffney (1990: figs. 92, 105). State 1, transversely elongate mesoplastra, are figured in Bräm (1965: pl. 1, fig. 2) and Lapparent de Broin (2001: fig. 1). The equidimensional, that is, rounder, mesoplastra can be seen in figure 264.</p> <p>Primitive condition: Medially meeting mesoplastra occur in Proganochelys and seem to be primitive for turtles. The two pairs of medially meeting mesoplastra seen in Proterochersis seem to be an autapomorphy for this taxon.</p> <p>Homoplasy: Medially meeting mesoplastra have evolved twice, with one being a reversal in Pelusios. Among pleurodires, mesoplastra have been lost at least three times: in Dortoka, Araripemys, and chelids. In cryptodires, they may have been lost only once.</p> <p>Discussion: Transverse mesoplastra not meeting on the midline are a synapomorphy for Platychelys + Notoemys, although there is another occurrence within extinct chelids and a similar condition exists in Pelusios broadleyi.</p> <p>If the equidimensional shape of Pelomedusa is primitive for Pelomedusidae, then state 2 is synapomorphic for Pelomedusoides; if not, state 2 is synapomorphic for the magnafamily Podocnemidera.</p> <p>This character is used in Gaffney et al. (1991), Rougier et al. (1995), Lapparent de Broin and Murelaga (1999), and Fuente and Iturralde-Vinent (2001).</p> <p>159. Plastron, trapezoidal entoplastron: entoplastron arrow-shaped with posterolateral processes (Proganochelys) 5 0; entoplastron more trapezoidal (Podocnemis) 5 1.</p> <p>Morphology: The entoplastron varies in shape in turtles, and this character is one aspect. The arrow-shaped entoplastron, state 0, is figured in Gaffney (1990: fig. 92), and the more trapezoidal shape is in figure 264.</p> <p>Primitive condition: Proganochelys has state 0.</p> <p>Homoplasy: Araripemys has a reversal to something similar to, but not identical to, the primitive condition.</p> <p>Discussion: The trapezoidal entoplastron, even though it may be somewhat irregularly shaped (e.g., Kayentachelys, Proterochersis), is a casichelydian synapomorphy.</p> <p>This character is used in Lapparent de Broin and Murelaga (1999).</p> <p>160. Plastron, epiplastra meet on midline: no, at least in ventral view (Proganochelys) 5 0; yes, meet on midline in ventral view (Foxemys) 5 1.</p> <p>Morphology: The separated condition, state 0, is figured in Gaffney (1990: figs. 92, 105) and the midline meeting condition in figure 264. Lapparent de Broin and Murelaga (1999) differentiated meeting in ventral view versus meeting in dorsal view, but the absence of a dorsal contact would only be relevant for Proganochelys and Palaeochersis and the condition is only known for Palaeochersis (which has the epiplastra separated dorsally and ventrally).</p> <p>Primitive condition: Presumably the complete separation of epiplastra by the entoplastron is primitive for turtles, as it is likely in Proganochelys and occurs in Palaeochersis and primitive cryptodires (Kayentachelys).</p> <p>Homoplasy: Cryptodires evolve medially meeting epiplastra independently of pleurodires.</p> <p>Discussion: This character is a synapomorphy for the parvorder Megapleurodira, consisting of all pleurodires minus Proterochersis. This character is used in Lapparent de Broin and Murelaga (1999) and Fuente and Iturralde-Vinent (2001).</p> <p>161. Plastron, dorsal epiplastral process: large, reaching or nearly reaching carapace (Proganochelys) 5 0; small or absent (Podocnemis) 5 1.</p> <p>Morphology: The dorsal process of the epiplastron is figured in Gaffney (1990: figs. 92–97). The absent condition can be seen in all the Pelomedusoides (e.g., Rütimeyer, 1873: pl. 8, fig. 6; Lapparent de Broin and Murelaga, 1999: pl. 2, fig. 5b).</p> <p>Primitive condition: Proganochelys, Palaeochersis, and Proterochersis have the presumed primitive condition of a large dorsal process of the epiplastron.</p> <p>Homoplasy: The dorsal process has been lost independently in cryptodires and within pleurodires.</p> <p>Discussion: This character is a synapomorphy for the parvorder Megapleurodira (all Pleurodira minus Proterochersis) and for the Cryptodira.</p> <p>This character is used in Rougier et al. (1995) and Fuente and Iturralde-Vinent (2001).</p> <p>162. Plastron, intergular scales: two (one pair) intergular scales (Proterochersis) 5 0; one intergular scale on midline (Foxemys) 51.</p> <p>Morphology: A pair of intergulars (state 0) is figured in Gaffney (1990: fig. 105). A single intergular can be seen in figure 264.</p> <p>Primitive condition: Proganochelys has one pair of intergulars.</p> <p>Homoplasy: None.</p> <p>Discussion: The single intergular is a synapomorphy for the parvorder Megapleurodira (all pleurodires minus Proterochersis). This character is used in Lapparent de Broin and Murelaga (1999) and Fuente and Iturralde-Vinent (2001).</p> <p>163. Plastron, gular projections: present (Proganochelys) 5 0; absent (Podocnemis) 5 1.</p> <p>Morphology: The conical anterior processes on the epiplastra and entoplastron that are formed where the gular scales are attached can be seen in Gaffney (1990: fig. 105). Figure 264, state 1, shows the smooth margin when the projections are absent.</p> <p>Primitive condition: Proganochelys and Proterochersis have gular projections.</p> <p>Homoplasy: The projections have been lost independently in cryptodires and within pleurodires. Lapparent de Broin (2000b) argued on the basis of morphology that the gular projections of Proterochersis and Proganochelys are not homologous, but this is ambiguous in the MPC.</p> <p>Discussion: This character is synapomorphic for the Megapleurodira, which is all Pleurodira minus Proterochersis.</p> <p>164. Plastron, anterior lobe of plastron short, wide at base, and semicircular in outline: width/length of 2.0 or less (Podocnemis) 5 0; width/length of more than 2.1 (Chedighaii) 5 1.</p> <p>Morphology: The plastron in primitive turtles like Proganochelys, Proterochersis, and Kayentachelys includes a long and narrow anterior lobe (Gaffney, 1990: fig. 105). However, the anterior lobe of the plastron in bothremydids and some other pleurodires is much shorter than its width across the base (state 1, fig. 264). Homology of this character is difficult to argue, howev- er, because of the simple nature of the character. This shape has been used as a character for the Bothremydidae (Antunes and Broin, 1988).</p> <p>Primitive condition: Clearly a plastron in which the anterior lobe is longer than wide is the primitive condition for turtles. Within the Pleurodira, chelids, pelomedusids, Araripemys, Euraxemys, and most podocnemidids have longer anterior plastral lobes that are longer than half the width at the base.</p> <p>Homoplasy: Bairdemys, a shweboemydine podocnemidid, shows a very similar, short, rounded, anterior plastral lobe that is broad across the base (fig. 275). In addition, a reversal to the longer, primitive condition occurs in the bothremydid Polysternon.</p> <p>Discussion: The addition of Cearachelys and the possible Galianemys, AMNH 30550 and AMNH 30551, to the shells known for bothremydids indicates that a short anterior plastral lobe is not universal for the family (fig. 314). The anterior lobe of Kurmademys is not completely known, but the hyoplastra have parallel lateral sides, which suggests that this form also did not have the very short, rounded anterior lobe seen in other bothremydids. Thus it appears that the short anterior plastral lobe is more likely a synapomorphy for the infrafamily Bothremydodda (Bothremydini and Taphrosphyini).</p> <p>This character is used in Antunes and Broin (1988) and Lapparent de Broin and Werner (1998).</p> <p>165. Plastron, pectoral scales on entoplastron: absent (Euraxemys) 5 0; present (Foxemys) 5 1.</p> <p>Morphology: The bony plastron of turtles is primitively covered by a set of seven plastral scales. The fourth set, the pectorals, covers most of the hyoplastron and, in the most primitive of turtles, the mesoplastron (state 0; Gaffney, 1990: fig. 105). In species in which the first three pairs of plastral scales are either reduced in size or absent, the pectorals may reach anteriorly to the entoplastron (state 1, fig. 259).</p> <p>Primitive condition: In Proganochelys, Proterochersis, Platychelys, Notoemys (Fernandez and Fuente, 1994), Euraxemys, Araripemys, and the Pelomedusidae, the pectoral scales are located posterior to the entoplastron. This seems to be the primitive condition. The primitive condition also appears to be present in the bothremydids, Cearachelys, and the probable Galianemys, AMNH 30050 and AMNH 30551.</p> <p>Homoplasy: Overlap of the pectoral scales onto the entoplastron may be a synapomorphy for the superfamily Podocnemidoidea, but if this is the case, then it is reversed at least in Cearachelys, Galianemys, and Rosasia. The pectoral scales also reach the entoplastron in some members of the Chelidae (Emydura), Trionychoidea (some Adocus, Basilemys, and Nanhsiungchelys), and Emydidae (Clemmys). The CI is 0.33.</p> <p>Discussion: Among the bothremydids for which we have data, only Cearachelys, Galianemys, and Rosasia lack this overlap.</p> <p>A variant of this character is used in Lapparent de Broin and Murelaga (1999).</p> <p>166. Plastron, pectoral scales on epiplastron: no, far behind epiplastra (Cearachelys) 5 0; yes, on epiplastra or epiplastronhyoplastron suture (Foxemys) 5 1.</p> <p>Morphology: The bony plastron of turtles is primitively covered by a set of seven plastral scales. The fourth set, the pectorals, covers most of the hyoplastron and, in the most primitive of turtles, the mesoplastron (state 0; Gaffney, 1990: fig. 105). In species in which the first three scale pairs are reduced in size or absent, the pectorals may reach anteriorly to the epiplastron (state 1, fig. 259).</p> <p>Primitive condition: Absence of pectoral scale-epiplastron contact seems to be the primitive condition. It appears to be absent in basal Pelomedusoides including Araripemys, Euraxemys, the probable Galianemys (AMNH 30050 and AMNH 30551), Cearachelys, and Rosasia.</p> <p>Homoplasy: This contact occurs in most podocnemidids (but it is absent in at least some Podocnemis erythrocephala, P. sextuberculata, P. unifilis, and Peltocephalus).</p> <p>Discussion: The derived condition of this character is present in Kurmademys, Polysternon, Foxemys, and Elochelys (including Elochelys convenarum Laurent et al., 2002). This character supports monophyly of the subtribe Foxemydina (Polysternon,</p> <p>Foxemys, Elochelys) within the tribe Bothremydini.</p> <p>167. Plastron, pectoral-abdominal scale sulcus crosses mesoplastron: yes (Cearachelys)</p> <p>5 0; no, anterior to mesoplastron (Kurmademys) 5 1.</p> <p>Morphology: The plastron in primitive turtles like Proganochelys, Proterochersis, and Kayentachelys includes large medially meeting mesoplastra that are covered in part by the pectoral and abdominal scales. Thus, the pectoral-abdominal scale sulcus crosses the mesoplastron primitively (state 0; Gaffney, 1990: fig. 105) as well as in later turtles (state 0, figs. 258, 264). In more derived turtles in which the mesoplastra are present, this sulcus may be anterior to the mesoplastron (state 1, fig. 259).</p> <p>Primitive condition: Contact of the pectoral-abdominal sulcus on the mesoplastron is clearly the primitive condition for turtles. The primitive condition is also seen in pleurodires such as Platychelys, Euraxemys, Bothremys, Rosasia, Pelomedusa, and some Podocnemis. This feature appears to show the primitive condition in most of the Bothremydidae.</p> <p>Homoplasy: The known distribution of this relatively homoplastic character within the Pleurodira suggests that is has appeared at least four times within the Bothremydidae alone. The CI is 0.25.</p> <p>Discussion: This character supports monophyly of the subtribe Foxemydina within the Bothremydini.</p> <p>This character is used by Antunes and Broin (1988), and Meylan (1996).</p> <p>168. Plastron, size and shape of ischial suture: attachment absent (Proganochelys) 5 0; large and linear or V-shaped (Podocnemis) 5 1; small and round or triangular (Taphrosphys) 5 2.</p> <p>Morphology: In all pleurodires the pelvis sutures to the carapace dorsally and to the xiphiplastron ventrally. The pubic attachment is typically a narrow diagonal suture angled from posterolateral to anteromedial in the middle of the xiphiplastron and does not vary very much. The ischial scar is more variable in shape. In most forms it is a linear or V-shaped contact that is nearly as large as or larger than the pubic suture and is located along the posteromedial portion of the xiphiplastron (state 1, fig. 259, 260; Zangerl, 1948: fig. 11). In a few bothremydid taxa (state 2, fig. 265; Gaffney, 1975a: fig. 11) this suture is reduced to a small circle, much smaller than the pubic scar.</p> <p>Primitive condition: The absent state is primitive for turtles; state 1 is primitive for pleurodires.</p> <p>Homoplasy: The ischial suture of Araripemys is also quite small, but it is located more posteriorly on the posterior limits of the xiphiplastron.</p> <p>Discussion: The derived condition of state 2, a relatively small, circular or triangular ischial suture on the xiphiplastron, is known only in Taphrosphys sulcatus, T. congolensis, and Ummulisani and is an equivocal Taphrosphyini synapomorphy. The presence of an ischial attachment scar is a pleurodire synapomorphy.</p> <p>169. Plastron, posterior lobe wider than pelvis: no, pelvis visible in ventral view (Proganochelys) 5 0; yes, pelvis hidden by wide posterior lobe (Podocnemis) 5 1.</p> <p>Morphology: The posterior lobe of the plastron is relatively narrow and V-shaped in Proganochelys and Palaeochersis, but wider and U-shaped in most Casichelydia (state 1, fig. 264). Although this character is somewhat subjective, the degree of pelvis exposure in ventral view helps make it more objective (compare Gaffney [1990: fig. 88] and Rougier et al. [1995: fig. 2] with Gaffney and Meylan [1991: 335]).</p> <p>Primitive condition: Based on Proganochelys, the narrow posterior lobe is primitive.</p> <p>Homoplasy: None in the MPC, but within Eucryptodira a narrow posterior plastron exposing the pelvis has evolved in chelydrids, trionychids, and a number of extinct forms.</p> <p>Discussion: Although the wide posterior lobe is a synapomorphy for Casichelydia, it is such a simple character, with homoplasy within cryptodires, that its usefulness is limited.</p> <p>This character is used in Lapparent de Broin and Murelaga (1999) as ‘‘pelvis width … pelvis wider than posterior lobe’’, but it is the plastron that is varying in size, not the pelvis.</p> <p>170. Plastron, intergular scale: small (Cearachelys) 5 0; large intergular, separating gulars and humerals (Taphrosphys) 5 1; large intergular, very small gulars, and partial humeral separation (Dortoka) 5 2.</p> <p>Morphology: The intergular scales are the anteriormost scales of the plastron. In Proganochelys, Proterochersis, and Kayentachelys they are relatively short scales that cover the anterior one-third of an anteriorly exposed entoplastron (state 0; Gaffney, 1990: fig. 105). In the genus Taphrosphys among the Pelomedusoides and in some chelids, the intergular coverage of the entoplastron is much expanded and it separates both the gular and the humeral scales (state 1, fig. 265). State two occurs only in Dortoka in our analysis.</p> <p>Primitive condition: The small intergular (paired or single) widely occurs in outgroups.</p> <p>Homoplasy: Hydromedusa is close to the Taphrosphys condition. Within the Bothremydidae, a large intergular occurs twice: in the Taphrosphyini and in Elochelys.</p> <p>Discussion: Within the Bothremydidae, the derived condition is a synapomorphy for Ummulisani + Taphrosphys. This character has been used to argue for the close relation of Elochelys and Taphrosphys (Lapparent de Broin and Werner, 1998: 163); however, our analysis suggests a close relationship among Elochelys, Foxemys, and Polysternon, requiring the large intergular to be acquired twice within the Bothremydidae.</p> <p>The relative sizes of the anterior plastral scales vary considerably in turtles. However, most of this variation is relatively continuous and does not form readily recognizable groupings. This character is one attempt to use this variation but does not attempt to use all of it.</p> <p>171. Plastron, axillaryłinguinal scales: present (Kayentachelys) 5 0; absent (Emydura) 5 1.</p> <p>Morphology: The small bridge scales can be seen in cryptodire shells (state 0, Zangerl, 1969: fig. 1). State 1 is their absence (fig. 258).</p> <p>Primitive condition: The absence of information about these scales in the outgroups (Proganochelys, Australochelys, Palaeochersis) makes it difficult to determine the primitive chelonian condition; presumably the presence of the scales is primitive.</p> <p>Homoplasy: None known in pleurodires, although there may be multiple losses within Cryptodira.</p> <p>Discussion: A problem with this character is the frequent damage to the bridge area of shells, making it difficult to determine the presence or absence of axillary or inguinal scales. In the MPC, Proterochersis is the only pleurodire definitely known to have these scales (Gaffney, 1990: fig. 105), so their absence is a Megapleurodira synapomorphy.</p> <p>172. Plastron, abdominal scale narrow: abdominal midline sulcus length equals or exceeds that of anal scale (Podocnemis) 5 0; abdominal midline length less than anal scales (Taphrosphys) 5 1; abdominal scales do not meet on the midline (Araripemys) 5 2.</p> <p>Morphology: Most of the paired scales of the turtle plastron meet and share a common sulcus on the midline. The length of that midline sulcus for the abdominal scute is primitively one of the longest such midline sulci and is equal to or longer than the length of the anal scales at the midline (state 0, figs. 257–264). In some bothremydids, the abdominal scale is significantly narrowed on the midline (state 1, figs. 265, 267). In Araripemys the abdominal scales do not meet on the midline (state 2; Meylan, 1996: fig. 2).</p> <p>Primitive condition: Abdominal scales in Proganochelys, Kayentachelys, and most Selmacryptodira are broad at the midline, suggesting that this is the primitive condition.</p> <p>Homoplasy: The narrowed condition appears to occur several times within the Pleurodira. Among the Cryptodira, lateral displacement of the abdominals and loss occur in the Chelydridae and Kinosternidae (Hutchison and Bramble, 1981).</p> <p>Discussion: Although this character shows homoplasy, it occurs only once within the Podocnemidoidea and, in the MPC, is a synapomorphy of a subset of the Taphrosphyini: Taphrosphys + Ummulisani.</p> <p>173. Plastron, anterior lobe reaches carapace edge: anterior margin of plastron reaches same level or beyond anterior margin of carapace (Cearachelys) 5 0; anterior margin of plastron well posterior to the anterior margin of the carapace (Foxemys) 5 1.</p> <p>Morphology: In most turtles the anterior lobe of the plastron is nearly as long as or longer than the anterior margin of the carapace. This can be seen in the primitive turtles Proganochelys, Proterochersis, and Kayentachelys (state 0; Gaffney, 1990: fig. 105). This is also the case in chelids, podocnemidids, pelomedusids, Euraxemys, Araripemys, and some bothremydids such as the probable Galianemys (AMNH 30550 and AMNH 30551) and Cearachelys. In the known Bothremydini the anterior limit of the plastron is well posterior to the anterior limit of the carapace (state 1, fig. 264).</p> <p>Primitive condition: Approximate alignment of the anterior ends of the plastron and carapace is considered to be the primitive condition for turtles.</p> <p>Homoplasy: In addition to those bothremydids with the derived condition described above, this condition occurs in some cryptodires with reduced plastra including Chelydra, Macrochelys, Staurotypus, Claudius, and Sternotherus.</p> <p>Discussion: This character is a synapomorphy for the tribe Bothremydini. The character is gradational at best, and it can be ambiguous if the articulated carapace and plastron are held at varying angles of view.</p> <p>174. Plastron, anal notch: absent (Kayentachelys) 5 0; present (Taphrosphys) 5 1.</p> <p>Morphology: The posterior lobe of the plastron has a recessed or embayed posterior margin on the midline (state 1, fig. 264).</p> <p>Primitive condition: The straight or posteriorly convex margin is primitive, as this occurs in Proganochelys (Gaffney, 1990) and Palaeochersis (Rougier et al., 1995).</p> <p>Homoplasy: None known in the MPC, but within Selmacryptodira many taxa may acquire at least a shallow anal notch, and within Chelidae some (e.g., some Chelodina) may also have a nearly absent anal notch.</p> <p>Discussion: The anal or xiphiplastral notch is a pleurodire synapomorphy, possibly related to the sutured pelvis.</p> <p>The character is used in Antunes and Broin (1988), Lapparent de Broin and Murelaga (1999), Lapparent de Broin (2000b), and Fuente and Iturralde-Vinent (2001).</p> <p>175. Shell, surface texture: surface rough with radiating ridges diverging from the posteromedial part (growth center) of the vertebral and pleural scale areas, as in Proganochelys 5 0; weakly granulated polygons, ‘‘pelomedusoid’’ pattern, also as in chelids 5 1; strongly granulated polygons, as in Taphrosphys 5 2; fine, striated ridges as in Polysternon 5 3; smooth, as in Cearachelys 5 4; numerous small pits, as in Araripemys 5 5; texture as in Dortoka 5 6.</p> <p>Morphology: The surface of the shell of many turtles is textured or sculptured; in others the shell is quite smooth. Within the Pleurodira a few species have radiating patterns of raised ridges, including Platychelys and Notoemys (state 0). Others, such as Araripemys, have patterns of numerous small pits (state 5). In certain members of the Bothremydidae, Chelidae, and Podocnemididae, there is a pattern of reticulate and anastomosing furrows and/or long striations that do not radiate from growth centers (state 1). At least in the Podocnemididae, these may be limited to the bridge. Broin (1977) called this texture ‘‘décoration pélomédusidienne’’. She described it as fine vascular grooves more or less dichotomous and discontinuous.</p> <p>Primitive condition: The shell surface of Proganochelys has a pattern of radiating raised ridges (state 0; Gaffney, 1990: figs. 73, 74). The same pattern appears to have been present in Proterochersis, Platychelys, and Notoemys. This may be the primitive condition for pleurodires. However, within the Pelomedusoides, neither the pelomedusids nor most podocnemidids have well-developed shell surface texture.</p> <p>Homoplasy: Shell surface sculpturing similar to that observed within some bothremydines occurs also in some chelids (AMNH 103702) and some Podocnemis.</p> <p>Discussion: The pattern of reticulate furrows and/or long striations has been used to recognize shell material of the Bothremydidae (Antunes and Broin, 1988: character C-8; Lapparent de Broin 2000b: 67) or Taphrosphys (Antunes and Broin, 1988; character H- 1; Broin, 1977; Lapparent de Broin and Werner, 1998: 41). Lapparent de Broin (2000b) argued that the carapace in bothremydids is more strongly decorated than in the other Pelomedusoides; that there are deeper short dichotomous sulci similar to marine cryptodires in Bothremys and sulci often united into salient polygons in Taphrosphys.</p> <p>In our survey of bothremydid shells, we have found some inconsistencies in the distribution of these characters. In the primitive bothremydids, Kurmademys and Cearachelys, there is an extremely fine surface texture of very small raised areas that are only visible under magnification. Also, there are Taphrosphys -like polygons in Araiochelys, a bothremydine on the basis of skull morphology. Polysternon and Foxemys, also bothremydines, have surface texture, but these do not resemble those of other bothremydids. Polysternon is described (Broin, 1977) as having grooves that are deeper and larger than those generally seen in ‘‘décoration pélomédusidienne’’. They are described as sinuous, longitudinal and continuous, and disposed in scale areas of the carapace anterior-posteriorly (Broin, 1977).</p> <p>The senior author thinks that this character should be dropped because the various states are difficult to identify objectively and consistently over a wide range of taxa. Making limited comparisons at the specific level for alpha taxonomic decisions should be done, but wide comparisons of all pleurodires becomes very subjective. Attempts to use surface texture in the highly ornamented Trionychidae have led to similar frustration. However, removing the character produces the same MPC. Nonetheless, state 1, if it can be recognized consistently, is a synapomorphy for Eupleurodira.</p> <p>Innumerable authors have used surface texture as a character in studies of pleurodires, with some of the more explicit being Antunes and Broin (1988), Lapparent de Broin and Werner (1998), Lapparent de Broin and Murelaga (1999), and Lapparent de Broin (2000b). Lapparent de Broin and Murelaga (1999) use ‘‘decoration’’ states, similar to the ones used here.</p> <p>SUMMARY</p> <p>This study shows that pleurodires had a more extensive and more complex evolutionary history than has been realized. The discovery of new taxa of extinct groups has revealed a diversity of morphologies indicating a remarkable diversity of feeding and sensory strategies. The recognition of this new diversity is based on the discovery and description of many new skulls of pleurodires in this and other recent papers. Most previous work has been based on the shell, which in pleurodires in general, and in the Pelomedusoides in particular, is relatively conservative morphologically, masking the magnitude of pleurodire diversity.</p> <p>The known history of the Pleurodira begins in the Late Triassic of Germany with the very high-domed, tortoiselike shells of Proterochersis. More than two dozen Proterochersis shells have been found in freshwater, stream-deposited sediments. Although they may have been aquatic, the high-domed shell is commonly assumed to indicate purely terrestrial turtles, however, it is also consistent with an adaptive response to large predators, like phytosaurs and metoposaurs. Although known only from the shell, Proterochersis is hypothesized as the sister taxon to all other pleurodires because it lacks the reduced scale arrangement of other pleurodires. Between the Late Triassic and Late Jurassic there is a long hiatus in the pleurodire record. The Late Jurassic yields a sparse pleurodire fauna of near-shore marine taxa of the family Platychelyidae, which is known from central Europe and the Caribbean. This family survives into the Early Cretaceous of South America. The Platychelyidae is the sister group to all remaining pleurodires, that is, the nanorder Eupleurodira consisting of the hyperfamilies Cheloides and Pelomedusoides.</p> <p>It is in the latter part of the Early Cretaceous that pleurodire diversity sharply increases, supporting the idea that a significant amount of the earlier record is missing. The Cheloides, consisting of the family Chelidae, is the sister group to the Pelomedusoides. Chelids appear in the fossil record in the Albian at about the same time as the Pelomedusoides, but it is likely that this basal divergence took place earlier because of the high diversity of Pelomedusoides in the Early Cretaceous that we have been able to document with this study. Evidence for monophyly of the Chelidae is supported by the presence in all chelids of biconvex fifth and biconcave seventh cervical vertebrae (character 128) and the extreme cheek emargination extending into the temporal region (character 39).</p> <p>At least four major clades of Pelomedusoides are known by the Albian. These are based on the genera Araripemys (Araripemydidae), Euraxemys (Euraxemydidae), Brasilemys (Podocnemidinura), and Cearachelys (Bothremydidae) from the Albian Santana Formation of Brazil, which shows that the major groups of Pelomedusoides were already established. A possible fifth lineage is Teneremys, from the Early Cretaceous of northern Africa. Based primarily on shell characters, Teneremys is resolved in this study as the sister taxon to the superfamily Podocnemidoidea, but it is as yet too poorly known for a well-tested relationship hypothesis.</p> <p>The family Araripemydidae consists of one taxon, Araripemys barretoi from the Aptian– Albian of Brazil. Description of new cranial material suggests a possible sister-group relationship to the extant family Pelomedusidae based on extensive temporal and cheek emargination (character 14), but this relationship is only weakly supported. Araripemys, although highly autapomorphic in many features, may represent the first record of the Pelomedusidae, a lineage still important in the recent African fauna. Regardless of whether they are sister taxa, they are outgroups to all the remaining Pelomedusoides because they lack the advanced feature of a partial or full covering of the prootic (character 94). Araripemys is characterized by very thin, narrow triturating surfaces and a shell that lacks mesoplastra and has the first costals reaching the shell margin. Araripemys was a near-shore, probably marine, possibly freshwater predator, very similar in habitus to recent turtles that prey on fish (trionychids, long-necked chelids).</p> <p>The new family Euraxemydidae consists of two new genera: Euraxemys essweini, n. gen. et sp., from the Albian Santana Formation of Brazil, and Dirqadim schaefferi, n. gen. et sp., from the Cenomanian Kem Kem beds of Morocco. Members of the Euraxemydidae share the unique possession of a medial process of the quadrate partially covering the prootic (character 94) and narrowly contacting a ventral process of the exoccipital, in contrast to all other pleurodires, which have either complete exposure or complete covering of the prootic ventrally. Furthermore, they possess a ventral process of the exoccipital that is exposed at the lateral margin of the basioccipital in an elongate foot (character 86). The Euraxemydidae is hypothesized as the sister group to the families Podocnemididae and Bothremydidae, which together form the superfamily Podocnemidoidea. Members of the superfamily Podocnemidoidea have the processus interfenestralis of the opisthotic and most of the prootic covered ventrally by the quadrate and basisphenoid (characters 94 and 99). The Euraxemydidae provides a model for the primitive condition for many other characters in the superfamily Podocnemidoidea.</p> <p>Brasilemys is the oldest member of the diverse group represented by the family Podocnemididae, which in the Recent fauna contains eight species divided into three genera currently living in South America and Madagascar. Brasilemys, from the Albian Santana Formation, the Cenomanian Hamadachelys from Morocco, and the Podocnemididae make up the epifamily Podocnemidinura. This clade is united by the possession of a cavum pterygoidei formed by the basisphenoid and pterygoid (character 69). The family Podocnemididae is known from the Cretaceous to the Recent and is known from all continents except Australia and Antarctica.</p> <p>Cearachelys is the oldest known of the Bothremydidae, a now extinct family that appears to be the most diverse family among the Pleurodira, reaching its greatest diversity later in the Late Cretaceous and Paleogene. All pleurodires known from the Early Cretaceous Santana Formation, including Cearachelys, were probably near-shore marine species, although some may have been fresh-water. In the Santana fauna, Euraxemys and Brasilemys may have been more generalized predators, with Araripemys more specialized for fish-eating. However, it is Cearachelys that may have begun the bothremydid trend toward a crushing feeding apparatus with a habitus similar to that of the Recent emydid Malaclemys.</p> <p>The Late Cretaceous reveals the persistence of euraxemydids in North Africa and a slight increase in diversity of podocnemidids in South America. The big event in pleurodire evolution at this time, however, is the explosive radiation of the Bothremydidae. This rapid expansion in morphological diversity can be observed in four clades, recognized as tribes, namely the Kurmademydini, Cearachelyini, Bothremydini, and Taphrosphyini. Although the oldest bothremydid is the Albian Cearachelys from Brazil, the most basal clade, and sister group to all other bothremydids, is the Maastrichtian tribe Kurmademydini from India. The two genera in the Kurmademydini have extensive temporal and cheek emargination. Kurmademys has a broad, triangular triturating surface, while that of Sankuchemys is narrower, with an accessory triturating ridge. The phylogenetic position of the Kurmademydini is based, among other characters, on the persistence of the fossa precolumellaris (character 56), which is absent in all other bothremydids. The Kurmademydini were most likely freshwater forms with lifestyles resembling those of the Recent pelomedusids Pelomedusa and Pelusios.</p> <p>The tribe Cearachelyini consists of two genera, Cearachelys from the Albian of Brazil and Galianemys from the Cenomanian of Morocco. They have the triangular, posteriorly expanded triturating surfaces typical of bothremydids (character 34). Their monophyly is supported by the presence of a jugal that is retracted from the orbital margin (character 20). While the Kurmademydini are found in freshwater sediments, as is Galianemys, Cearachelys is in the presumably near-shore marine Santana Formation. The broad jaws of the Cearachelyini genera suggest that their lifestyles may have been comparable to broad-jawed emydids like Graptemys and Malaclemys.</p> <p>The tribe Bothremydini is characterized by the very broad preorbital part of the skull with very wide triturating surfaces, often with conical pits on the skull and jaws (characters 34, 35). The function of the pits is unknown, but they may have allowed the animal to hold and crush slippery, ovoid prey, like gastropods. The Bothremydini are the most longranging bothremydids, extending from the Late Cretaceous Santonian to the Eocene Ypresian. Geographically, this clade is widespread, extending from its peak diversity area of North Africa to North America, Europe, and the Middle East. Although most are near-shore marine, the European subtribe Foxemydina and the North American species Chedghaii hutchisoni are known from freshwater sediments. This radiation of broad-jawed, probable molluscivores is unique among turtles. In the genus Graptemys, the females of four species approach the morphology seen in the Bothremydini, but they are much smaller, nonmarine turtles with a very restricted distribution. Among marine cryptodires many species have enlarged triturating surfaces, but none has produced the inflated face seen in members of this tribe.</p> <p>The tribe Bothremydini consists of Foxemys mechinorum from the CampanianMaastrichtian of France; Polysternon provinciale from the Campanian of Europe; Zolhafah bella from the Maastrichtian Dakla Formation of Egypt; Rosasia soutoi from the Campanian–Maastrichtian of Portugal; Araiochelys hirayamai, n. gen. et sp. and Bothremys maghrebiana, n. sp. from the Danian phosphates of the Ouled Abdoun Basin, Morocco; Bothremys cooki from the Maastrichtian Navesink Formation of New Jersey; Bothremys kellyi, n. sp. from the Ypresian phosphates of the Ouled Abdoun Basin, Morocco; Bothremys arabicus from the Santonian of Jordan; Chedighaii hutchisoni, n. gen. et sp. from the Campanian Kirtland Formation of New Mexico; and Chedighaii barberi, n. gen. from the Campanian of Arkansas, Alabama, Kansas, and New Jersey.</p> <p>The tribe Taphrosphyini has a variety of triturating surfaces but lacks the wide, triangular surfaces typical of the other bothremydids. Members of the Taphrosphyini are characterized by the presence of a jugal-quadrate contact (character 22), the absence of a maxilla-quadratojugal contact (character 38), and the absence of a supraoccipital-quadrate contact (character 79). Among the Bothremydidae, the Taphrosphyini is the most diverse morphologically. The feeding surfaces show surprising variation. The long, narrow skull of Labrostochelys is similar to the skull of some fish-eating trionychids, while the very short skull of Phosphatochelys is similar to some cheloniids. Other skulls, such as those of Azabbaremys and Arenila, are large and massive, but without broadly expanded triturating surfaces, while Ummulisani has very narrow and deep labial ridges. The nasal regions of Taphrosphyini also show wide diversity. Rhothonemys has nasal openings and cavities that are more than twice the size of the orbits, in contrast to the nasal openings in Labrostochelys, which are smaller than the relatively small orbits. This diversity in the skull morphology of the Taphrosphyini is mostly evident in the Paleogene of North Africa, but the group is also known from the East Coast of North America, central Africa, and (based on shells) Europe and South America. All the Taphrosphyini are near-shore marine.</p> <p>The tribe Taphrosphyini consists of Taphrosphys sulcatus from the Danian Hornerstown Formation of New Jersey; Taphrosphys congolensis from the Paleocene of Cabinda, west Africa; Taphrosphys ippolitoi, n. sp. and Labrostochelys galkini, n. gen. et sp. from the Danian phosphates of the Ouled Abdoun Basin, Morocco; Phosphatochelys tedfordi and Ummulisani rutgersensis, n. gen. et sp. from the Ypresian phosphates of the Ouled Abdoun Basin of Morocco; Rhothonemys brinkmani, n. gen. et sp. from the Paleogene phosphates of the Ouled Abdoun Basin of Morocco; Azabbaremys moragjonesi from the Paleocene Teberemt Formation of Mali; Nigeremys gigantea from the Maastrichtian of Niger; and Arenila krebsi from the Maastrichtian Dakla Formation of Egypt.</p> <p>When the skull morphology of the members of the Taphrosphyini is considered alongside that of the other three tribes, it becomes apparent that the family Bothremydidae has the greatest range of skull forms of any turtle family yet known. In fact, the skull morphologies of many turtle families seem remarkably uniform in comparison (e.g., Testudinidae, Kinosternidae, Pelomedusidae, Trionychidae, Carettochelyidae). Even in families with relatively diverse skull morphologies (e.g., Geoemydidae, Chelidae), variation generally occurs in one or two major aspects of their structure (triturating surface and cheek completeness in geoemydids; cheek emargination in chelids). There are also families with bizarre skull morphologies (e.g. Nanhsiungchelyidae, Protostegidae), but these are not diverse, at least as they are now known. In no other family do we see the extremes exemplified by the skulls of Cearachelys, Bothremys, Labrostochelys, Azzabaremys, Rhothonemys, and Phosphatochleys. It is this remarkable variation in skull morphology that has allowed us to formulate a strong hypothesis of bothremydid relationships in spite of the presence in Pelomedusoides of remarkably uniform shells.</p> <p>A phylogenetic analysis of the core dataset of 41 taxa, 122 cranial characters, and 52 postcranial characters relies on comparative descriptions of these taxa. The analysis using PAUP results in one most parsimonious cladogram of 382 steps and a consistency index of 0.6. A Bremer decay analysis shows that the family Bothremydidae is strongly supported at five steps, the tribes Cearachelyini and Kurmademydini have an index of 2, and the tribe Taphrosphyini has an index of 3. The tribe Bothremydini becomes unresolved at one step and is the most weakly supported of these groups. The addition of selected, shell-only taxa with low missing data to the core dataset results in one equally parsimonious cladogram, which is resolved as (Proterochersis (Platychelyidae (Dortoka (Chelidae (Pelomedusidae + Araripemys) (Euraxemydidae (Teneremys (Podocnemididae + Hamadachelys + Brasilemys (Bothremydidae)))))))). A partitioned dataset consisting only of cranial characters (excluding all shell-only taxa) results in one equally parsimonious cladogram identical to the most parsimonious cladogram resulting from the whole dataset; however, a partitioned dataset consisting only of postcranial characters (excluding all skull-only taxa) resulted in 2704 trees, the consensus of which lacks resolution for nearly all of the Pelomedusoides, but which does resolve more basal pleurodires.</p> </div>	https://treatment.plazi.org/id/4E7B8791CD55FD34FD7FFE7816278D13	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	GAFFNEY, EUGENE S;TONG, HAIYAN;MEYLAN, PETER A	GAFFNEY, EUGENE S, TONG, HAIYAN, MEYLAN, PETER A (2006): EVOLUTION OF THE SIDE-NECKED TURTLES: THE FAMILIES BOTHREMYDIDAE, EURAXEMYDIDAE, AND ARARIPEMYDIDAE. Bulletin of the American Museum of Natural History 300 (300): 1-698, DOI: 10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2, URL: http://dx.doi.org/10.1206/0003-0090(2006)300[1:eotstt]2.0.co;2
