taxonID	type	description	language	source
1160879CFFA8FFFCFD83FBCCFCF5FE67.taxon	description	(Figs. 3 A – C) Specimen — CMM-V- 4776, left epiplastron found by Melville Hurd. Locality, horizon, and age — Found on the beach at the foot of the bluff west of Loyola Retreat, 1.7 miles north of Popes Creek in southern Charles County, Maryland; the color, density, and the presence of very fine silvery mica adhering to the bone surface all indicate that it came from the adjacent Woodstock Member (Bed A) of the Nanjemoy Formation; early Eocene (late Ypresian; within nannofossil zone NP 12). Description — CMM-V- 4776, epiplastron broadly attached suturally to right epiplastron and hyoplastron, anterior portion of contact with the entoplastron shingled. Two sulcal grooves present on the external (ventral) surface. Anterior sulcal groove trends anteriorly; posterior sulcal groove trends more laterally than anteriorly.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFA8FFFCFD83FBCCFCF5FE67.taxon	discussion	Remarks — The shape of the left epiplastron is rather similar to that of both the bothremydid Chedighaii Gaffney, Tong & Meylan 2006 and the baenid Baena Leidy 1870. However, the reticulate pattern of grooves on the external surface is typical of bothremydids (e. g., Hay 1908, fig. 121) and the hypoplastral suture is transverse and somewhat anterolaterally directed as in bothremydids and not posterolaterally directed or pointed posteriorly as in baenids. Additionally, this specimen is large. It is more than twice the size of the epiplastra of adult early or middle Eocene Baena and, unlike in adult Baena, was not fused to its surrounding plastral bones (Hutchison 1984). Therefore, based on these features, this specimen is from a pleurodiran turtle and not a baenid. Although there is not enough material to allow assignment of this specimen to a specific genus or species of bothremydid turtle, it does show that bothremydid turtles persisted in the eastern United States through most or all of the early Eocene. ity 7 — Bluffs along Pamunkey River, forming in this area the boundary between King William County (north) and New Kent County (south), Virginia. BOTHREMYDINAE Gaffney, Tong & Meylan 2006	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFADFFFDFD90FE6FFAF7FEEA.taxon	description	(Figs. 4 – 7) Synonymy — Osteopygis roundsi (partem) Weems 1988.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFADFFFDFD90FE6FFAF7FEEA.taxon	materials_examined	Holotype — CMM-V- 4755, slightly more than half of a carapace, nearly complete on its right side except for the first peripheral and in its medial region except for the nuchal and first and second neurals; on the left side only a fragment of the central and posterior portions of the carapace are preserved. Type locality, horizon, and age — This specimen was recovered at a construction site in Fort Washington, west of Maryland Route 210, Prince Georges County, Maryland (in the vicinity of 38.7435 N, 77.0104 W); in a block of lime-cemented rock broken from an Aquia Formation hard-bed, very probably “ Zone 3 ” or “ Zone 5 ” of the Piscataway Member (Clark and Martin 1901); late Paleocene (early Thanetian). Referred specimen — USNM 357710, left hyoplastron and hypoplastron, discussed and illustrated in Weems (1988). Locality, horizon, and age — Found in the Blue Banks south of Liverpool Point, eastern bank of the Potomac River, Prince Georges County, Maryland; from “ zone 2 ” of the lower Piscataway Member of the Aquia Formation (Clark and Martin 1901); late Paleocene (early Thanetian).	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFADFFFDFD90FE6FFAF7FEEA.taxon	etymology	Etymology — The species is named for Dr. Peter Kranz, who recovered and donated the holotype.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFADFFFDFD90FE6FFAF7FEEA.taxon	diagnosis	Diagnosis — The deeply impressed sulcal grooves, the wide but only ligamentously connected plastral bridge, and the large size of Judithemys kranzi readily places it among the “ Macrobaenidae. ” Of the two North American genera in this family, J. kranzi differs from O. emarginatus in having only two suprapygals, a wide nuchal, a pygal that does not appear to be posteriorly elongated, and a hyoplastron with an external margin that shows a narrow outer anterior extension (Fig. 6). All of these traits are present in Judithemys. Compared to the two known species of Judithemys (Brinkman et al. 2010), J. kranzi differs from J. sukhanovi Parham and Hutchison 2003 in having a much more regularly elliptical-shaped carapace not much widened posteriorly, neurals much longer than wide, a seventh neural that is distinctly shortened anteroposteriorly, and much more elongate second and third vertebral scales. It differs from J. backmani (Russell 1934) in having a relatively wider nuchal, a relatively longer second vertebral scale, a relatively narrower fifth vertebral scale, and a sulcus on the eighth costal located near and along its posterior border and not near its anterior edge.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFADFFFDFD90FE6FFAF7FEEA.taxon	description	Description — The carapace is elliptical, longer than wide, with anterior border rounded and posterior border slightly scalloped at the lateral margins of the pygal (Fig. 5). The bone has an anastomosing surface texture and deeply impressed sulcal grooves. Nuchal much wider than long and apparently somewhat “ T ” - shaped. Neurals are longer than wide except for the seventh which is shortened and about as wide as long. Two suprapygals are present; the pygal is smaller and anteroposteriorly shorter than the adjacent peripherals. The vertebral scales are hexagonal, with the first being wide and short, the second being longer than wide, the third and fourth being about as long as wide, and the fifth wider than long.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFADFFFDFD90FE6FFAF7FEEA.taxon	discussion	Remarks — The pygal region is variable in “ macrobaenids, ” so comparison of that region with other species, based only on a single specimen, is not instructive. These similarities and differences are summarized in Table 1. This specimen is the first reported occurrence of Judithemys in the eastern United States, though part of its plastron was previously illustrated by Weems (1988) and incorrectly assigned to Osteopygis roundsi.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFA0FFF1FEAEFC8CFDA8F834.taxon	description	Locality, horizon, and age — Found along the western bank of Aquia Creek at the base of “ zone 2 ” of the lower Piscataway Member of the Aquia Formation (Clark and Martin 1901); late Paleocene (early Thanetian).	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFA0FFF1FEAEFC8CFDA8F834.taxon	discussion	Remarks — Weems (1988) assigned this taxon to the family Sinemydidae Yeh 1963 but new material and more extensive descriptions of Sinemys Wiman 1930 (Brinkman and Peng 1993, Sukhanov 2000) have documented a suite of diagnostic features that do not support close relationship between Sinemys and Planetochelys. Hutchison (2012) has restudied the type specimen of Planetochelys savoiei, reinterpreted its suprapygal region, and described a new closely related species from the western United States, P. dithyros Hutchison 2012. Unlike the type specimen of P. savoiei, the new species includes the anterior portion of the carapace and plastron. The occasional presence in P. dithyros of extragular scales indicates that it is too primitive to be included within the chelydrid-testudinoid lineage and most likely lies near the adocid grade of trionychians (Hutchison 2012). Planetochelys has a number of specializations that show it to have been a terrestrial turtle that had evolved a carapace and plastron much like that of a “ box turtle, ” even though it is not closely related to the emydid and kinosternid turtles that independently have evolved a plastral hinge to allow the shell to partly or wholly close. Because of its unique combination of primitive and derived features, Planetochelys is not particularly close to any other turtles and has been placed in its own family (Hutchison 2012).	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFA7FFF6FF62FD5FFB5FFB85.taxon	description	(Figs. 8 L – N) Specimens — CMM-V- 4761, neural element found by Peter Kranz; CMM-V- 4760, seventh right costal found by Michael Smigaj. Locality, horizon, and age — The neural was found at the foot of the bluffs west of Fort Washington on the shore of the Potomac River, Prince Georges County, Maryland. The specimen probably came from the base of the Piscataway Member of the Aquia Formation (late Paleocene, early Thanetian), but it seems likely it was reworked from the Brightseat Formation (early Paleocene, Danian). The costal was found at a site along Central Avenue just east of Washington, D. C., in Prince Georges County, Maryland. The specimen came either from near the base of the Piscataway Member of the Aquia Formation (late Paleocene, early Thanetian) or from the Brightseat Formation (early Paleocene, Danian). Description — Neural and costal both have a distinctive surface sculpture composed of rounded shallow pits separated by flat-topped interconnected ridges. Posterior border of costal abutted a relatively small eighth costal.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFA7FFF6FF62FD5FFB5FFB85.taxon	discussion	Remarks — There is little that can be gleaned from these specimens that would allow any detailed identification within the family Trionychidae. The relatively small size of the eighth costal, as indicated by its nested border with the seventh costal, is typical of trionychine turtles but also is found in some cyclanorbines. Therefore, no definitive subfamily placement can be made. The pitting pattern on the external surface of the bones is distinctly different from that of the described Aquia Formation trionychid species “ Trionyx ” virginianus Clark 1895 referred below to the genus Aspideretoides Gardner, Russell & Brinkman 1995 so this material pertains to a different taxon of trionychid turtle. The pattern on the surface of these bones is quite similar to that of “ Trionyx ” halophilus (Cope 1870, Hay 1908), which was described from Maastrichtian strata in Delaware (Baird and Galton 1981). Aspideretoides species (Gardner et al. 1995), Axestemys puercensis (Hay 1908), and Oliveremys Vitek 2011 have a somewhat similar pattern of pits. Oliveremys is not known to range below the middle Eocene and has not been reported from anywhere in eastern North America, so it is very unlikely that this material would pertain to that genus. Axestemys and Aspideretoides are known to range from the Upper Cretaceous into or through the Paleocene (Williamson and Lucas 1993, Hutchison and Holroyd 2003, Jasinski et al. 2011), so “ T. ” halophilus might pertain to one of these genera. Unfortunately, the holotype material and the specimens described here are too fragmentary to assign to any genus with certainly, so the matter cannot be resolved. Therefore this material is referred to “ Trionyx ” halophilus for the sake of nomenclatural stability, while recognizing that the type material is not diagnosable and this species is a nomen dubium. It is possible that these specimens represent a turtle that survived into the very beginning of deposition of the Aquia Formation, but the total absence of any similar remains at any horizon above the very base of the Aquia Formation suggests that it is far more likely that these specimens originated in the Brightseat Formation and were reworked into the base of the immediately overlying Aquia Formation.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFA7FFF7FDB5FB96FA60FEC4.taxon	description	(Fig. 8 O) Specimen — CMM-V- 3283, third left costal found by William Counterman. Locality, horizon, and age — This costal was found in the bluffs north of Popes Creek and south of the Loyola Retreat in southern Charles County, Maryland. The specimen came from the upper part (B) of the Woodstock Member, Nanjemoy Formation; early Eocene (Ypresian, NP 13). Description — Costal elongate with no indication of sulcal grooves or any sutural border at its distal end for attachment to a peripheral element. Dorsal surface bears a coarse sculpture of pits and grooves, with pits predominating proximally and grooves predominating distally. Distal rib end protrudes beyond the costal only a short distance.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFA7FFF7FDB5FB96FA60FEC4.taxon	discussion	Remarks — The size, thickness, and external surface sculpture of this specimen are indistinguishable from material described by Cope (1869 a) as “ Trionyx ” pennatus, which apparently came from the age-equivalent early Eocene Manasquan Formation in New Jersey. The type material from New Jersey, the specimen described here, and similar early Eocene material described from the Fisher / Sullivan site in Stafford County, Virginia (Weems 1999) almost certainly pertain to one and the same taxon because all of this material is very similar and also because no other early Eocene species of trionychid turtle has been reported from anywhere in the eastern United States. Although Trionyx Forskål 1775 was once widely used as a generic designation for American Cenozoic soft-shell turtle specimens, the name does not properly apply to any American material (Meylan 1987). At the same time, however, there are no characteristics preserved in this Nanjemoy material that could clearly establish what the correct generic designation is or even to which subfamily of trionychids it pertains. It is possible, but far from certain, that it pertains to the living genus Apalone Rafinesque 1832. For now, the established name “ Trionyx ” pennatus is retained with Trionyx in quotes for nomenclatural stability, while recognizing that the type material is not diagnosable and this species is a nomen dubium.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFA6FFF5FD14FE0FFA4AFAC8.taxon	description	(Figs. 9 A – F, 10) Synonymy — Trionyx virginianus Clark 1895, Amyda virginiana (Lynn 1929), Aspideretes virginianus (Weems 1988).	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFA6FFF5FD14FE0FFA4AFAC8.taxon	type_taxon	Type species — Aspideretoides virginianus (Clark 1895).	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFA6FFF5FD14FE0FFA4AFAC8.taxon	diagnosis	Diagnosis – Costal plates up to 26 mm thick; sculpture consists of ridges and grooves oriented at right angles to the sutural borders; a few to many ridges cross the grooves, breaking them up into circular and elongate pits up to 5 mm in diameter (after Hay 1908). Expanded diagnosis — Carapace elliptical in shape, longer than wide, adult specimens over 60 cm in length; neurals and costals very thick with a ridge and groove sculpture pattern oriented generally at right angles to sutural boundaries and generally broken up by ridges crossing the grooves into circular to elongate pits; preneural present. Plastron strongly reduced; xiphiplastron similar in shape to that of Aspideretoides foveatus but less elongated anteroposteriorly, posterior border concave rather than convex as in A. foveatus, and much larger.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFA6FFF5FD14FE0FFA4AFAC8.taxon	materials_examined	Holotype — USNM- 9354, fragments of two costal elements. Hypodigm — USNM- 11944, a largely complete carapace illustrated in Weems (1988); CMM-V- 4756, a partial carapace found by Peter Kranz; CMM-V- 4768, largely complete right xiphiplastron found by Gary Grimsley; CMM-V- 4766, proximal portion of scapula found by Thomas G. Gibson. Locality, horizon, and age — The type material came from the high bluffs between Potomac Creek and Aquia Creek along the southern shore of the Potomac River in Stafford County, Virginia, as did the nearly complete carapace described in Lynn (1929) and Weems (1988). The scapula fragment was found by Thomas G. Gibson in “ Zone 4 ” of the Aquia Formation in these same bluffs. The right xiphiplastron was found in the Blue Banks south of Liverpool Point on the east bank of the Potomac River in “ Zone 2 ” of the Aquia Formation, Charles County, Maryland. All of these specimens came from the lower part of the Piscataway Member of the Aquia Formation; late Paleocene (early Thanetian).	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFA6FFF5FD14FE0FFA4AFAC8.taxon	discussion	Remarks — Clark’s “ Trionyx ” virginianus was referred by Weems (1988) to the genus Aspideretes because the carapace bears a large preneural element, which is present in that genus and not in the genus Trionyx. Since then, however, it has become apparent that the presence of a preneural is a primitive feature among the Trionychidae that has persisted in several quite different lineages, and that the genus name Aspideretes is applicable only to some Asian trionychines (Meylan 1987, Vitek 2012). Gardner et al. (1995) have erected the genus Aspideretoides to include Late Cretaceous to Early Cenozoic western American trionychine species that retain a preneural and also have similar and distinctive plastra. As discussed below, the discovery of a “ T. ” virginianus xiphiplastron that is very similar now makes it appropriate to assign this species to Aspideretoides. The referred xiphiplastron clearly pertains to Aspideretoides virginianus because (1) it comes from an animal too large to be the enigmatic basal Aquia or pre-Aquia trionychid “ Trionyx ” halophilus, (2) its ridge and trough sculpture pattern is like that of A. virginianus and unlike the pitted pattern of “ T. ” halophilus, and (3) this xiphiplastron was found at a locality that has produced numerous carapace examples of “ A. ” virginianus and no examples of “ T. ” halophilus. For all of these reasons, this xiphiplastron can be confidently assigned to A. virginianus. Its discovery for the first time allows comparison with the plastra of other trionychids known from the Late Cretaceous and Early Cenozoic of North America. North American Late Cretaceous and Cenozoic trionychids include representatives of both the subfamilies Plastomeninae Hay 1902 and Trionychinae. Most plastomenines have a preneural, but they also have a plastron that is much less reduced than in this species and most other trionychines; therefore referral to Plastomeninae is not indicated. Among Paleocene and Eocene trionychines, Apalone and Oliveremys differ from A. virginianus in that they both lack a preneural element. Axestemys is similar to A. virginianus in that it retains a preneural and attains a large size (greater than 60 cm), but it shows no close similarity in its xiphiplastra. The right xiphiplastron discussed here bears considerable resemblance to the xiphiplastra of Aspideretoides (Fig. 10), so reference of the species virginianus to the genus Aspideretoides is indicated. The detailed morphology of this xiphiplastron, however, is not identical to that of any known species of Aspideretoides, so the species name remains valid. Although the holotype of A. virginianus is very fragmentary and not directly diagnosable, the supplementary material discussed here and in Weems (1988) does provide adequate information to allow a unique diagnosis. The large size of the supplementary xiphiplastron and the large size and exceptional thickness of the supplementary carapace specimens indicate that all of this material pertains to a very large trionychine turtle comparable in size to the turtle from which the holotype specimens came. The only other trionychid turtle that possibly has ever been found in the Aquia Formation is “ Trionyx ” halophilus which, as discussed above, more probably is only present in the basalmost Aquia Formation as material reworked from the immediately underlying Brightseat Formation. Even if “ T. ” halophilus did survive into the base of the Aquia Formation, however, it is a much smaller species than A. virginianus and has a distinctly different surface sculpture. Considering that all of the material assigned here to A. virginianus was found within a very restricted stratigraphic interval (lower Piscataway Member of the Aquia Formation) in outcrops less than ten miles apart, there is no reason to doubt that all of the large, thick-shelled trionychid specimens from the Piscataway Member of the Aquia Formation represent a single species. The xiphiplastron of A. virginianus has a healed fracture which is discernable near its external and internal margins (shown in Fig. 10) but untraceable across its central region. This indicates that the xiphiplastron was fractured when the turtle was young, but the animal survived and its fracture healed almost entirely before the animal died.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFA4FFEAFDF3FA2FFB05FB51.taxon	description	Specimen — USNM 359002, nuchal, first neural, right and left first and second peripherals, and left third peripheral, described in Weems (1988). Locality, horizon, and age — Found in bluff between Aquia Creek and Potomac Creek, western bank of Potomac River, Stafford County, Virginia; nannofossils in the attached matrix indicate the specimen came from “ zone 6, ” Piscataway Member of the Aquia Formation (Clark and Martin 1901); late Paleocene (early Thanetian).	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFA4FFEAFDF3FA2FFB05FB51.taxon	discussion	Remarks — Weems (1988) assigned to Allopleuron insularis the anterior portion of a large but lightly built carapace found in the late Paleocene (early Thanetian) Piscataway Member of the Aquia Formation. This Aquia carapace has a peculiar first peripheral that is sutured to the second peripheral on both its distal and internal sides so that it is completely out of contact with the costoperipheral fontanelle. This condition is characteristic of a species found in the age equivalent late Paleocene (early Thanetian) Vincentown Formation of New Jersey that Cope named Lembonax insularis. Cope included three species in the genus Lembonax Cope 1870: L. polemicus Cope 1870 which is the type species, L. insularis Cope 1872 and L. propylaeus Cope 1872. Unfortunately, the type species of Lembonax is a nomen dubium (Weems 1988) and cannot be adequately defined. Because of this, Weems (1988) chose to refer Lembonax insularis to the similar (but not identical) Late Cretaceous turtle genus Allopleuron Baur 1888 (type species Allopleuron hoffmani (Gray 1831 )) as a new combination (A. insularis) and assigned Allopleuron to the Dermochelyidae. At that time, this assignment was in accord with the conclusion of Gaffney and Meylan (1988) and Hiramaya (1992) that Allopleuron was an aberrant protostegid or dermochelyid turtle. Somewhat later, however, Hirayama (1994) concluded that A. hoffmani was an aberrant pancheloniid turtle, and this placement has been followed since (Lapparent de Broin 2001, Karl 2007, Karl et al. 2012). In recent years two new species of Allopleuron have been named: A. lipsiense Karl 2007 from the early Oligocene of Germany and A. qazaqstanense Karl, Gröning, and Brauckmann 2012 from the early middle Eocene of Kazakhstan. These new records show that in Europe Allopleuron survived at least until the early Oligocene. Significantly, the three European species assigned to Allopleuron (A. hoffmani, A. qazaqstanense, and A. lipsiense) all have a normal progression of peripheral elements away from the nuchal, a nuchal that is anteroposteriorly short, and a first neural that is as long as or longer than wide (Karl et al. 2012: 164). This stands in marked contrast to the condition seen in “ A. ” insularis in which the second peripheral makes broad contact with the nuchal beneath the first peripheral so that the first peripheral is nested above the second peripheral-nuchal contact, the nuchal is relatively much narrower and more elongate, and the first neural is very wide. These are striking differences that clearly indicate that (1) “ A. ” insularis should not be referred to the European genus Allopleuron and (2) that Allopleuron henceforth should be considered to be an exclusively Eurasian genus. It still seems likely that the material included in Lembonax represents a dermochelyid rather than a pancheloniid turtle. Referral of the species Lembonax insularis to Eosphargis is proposed because the early Eocene dermochelyid Eosphargis gigas (Owen) Lydekker 1889 a also has a nuchal that is strongly indented anteriorly and because Lembonax occurs at a horizon equivalent in age to the oldest specimens of Eosphargis known from Denmark (Lapparent de Broin 2001). No skull or plastron material referable to Lembonax insularis has been found, so there is no way to perform a rigorous comparison between L. insularis and the two described European species of Eosphargis, E. gigas and E. breineri Nielsen 1959. In the absence of such material, there is no way to determine with certainty if “ A. ” insularis might be identical with E. gigas or E. breineri. Therefore, at least for now it seems most parsimonious to refer the long established and diagnosable species Lembonax insularis to Eosphargis as a third species, Eosphargis insularis. Eosphargis breineri was described as an Eocene dermochelyid (Nielsen 1959), but it is now known to be latest Paleocene in age (Bonde 1987). Therefore this species most probably is age equivalent to the late Thanetian Paspotansa Member of the Aquia and somewhat younger than the early Thanetian source horizon of E. insularis in both New Jersey and Maryland. It remains possible that E. breineri is synonymous with E. insularis. Until such time as this can be tested in a meaningful way, however, they should remain as separate species of slightly different age and distinctly different provenance.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFB8FFE9FEADFBDCFB75FBAB.taxon	description	Synonymy — Dollochelys coatesi Weems 1988, Catapleura repanda (partem) Hirayama 2006 Specimens — CMM-V- 4764, second left costal found by Jason Osborn; CMM-V- 4767, pygal found by Gary Grimsley; CMM-V- 4765, neural found by Mark Bennett. Locality, horizon, and age — Blue Banks south of Liverpool Point, Charles County, Maryland; “ Zone 2 ” of the Piscataway Member of the Aquia Formation (Clark and Martin 1901); late Paleocene (early Thanetian). Description — Left second costal, thin proximally (3 mm) thickening distally to moderately thin (5 mm), sulcal grooves discernable on dorsal surface. Anterior portion of distal end has sutures for attachment to an anterior peripheral; posterior portion forms the internal border of the anterior internal rim of the costoperipheral fontanelle. Nuchal hexagonal and only about 3 mm thick. Pygal attached to second suprapygal by only a narrow bridge of bone.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFB8FFE9FEADFBDCFB75FBAB.taxon	discussion	Remarks — Weems (1988) described this species and placed it in the genus Dollochelys Zangerl 1971. Since then, Hirayama (2006) concluded that Dollochelys is a junior synomym of Catapleura. This synonymy is accepted here. However, Hirayama also concluded that the three described species formerly in Dollochelys (D. casieri Zangerl 1971, D. atlantica (Zangerl 1953) and D. coatesi) are all essentially identical with C. repanda and thus are junior synonyms of that taxon. With this the present author disagrees. Many but not all of the features of D. coatesi are the same as in C. repanda, but a second specimen of C. coatesi illustrated here (Fig. 14 A) indicates by the position of its sulcal grooves that there was only a very narrow vertebral scale as in the type specimen of Catapleura coatesi and quite different from the much wider vertebral scale characteristic of C. repanda. Since no specimen has been found with a vertebral scale width intermediate between these two species, available evidence still clearly favors these being distinctly different species. The fact that C. coatesi is found in the late Paleocene Aquia Formation, while the type material of C. repanda and D. atlantica both come from the early Paleocene Hornerstown Formation, further casts doubt on any likely synonymy of C. coatesi with C. repanda and instead suggests that C. repanda is probably ancestral to C. coatesi.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFBDFFE2FF64F91CFD2DFAB2.taxon	description	(Figs. 14 D-H, 15) Synonymy – Osteopygis roundsi (partem) Weems 1988, Osteopygis wielandi (partem) Lynch & Parham 2003, Osteopygis wielandi (partem) Parham & Pyenson 2010.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFBDFFE2FF64F91CFD2DFAB2.taxon	materials_examined	Holotype – USNM 412108, crushed and slightly exploded skull imbedded in a nodule. Referred specimen – Cast of largely complete skull (CMM-V- 4825); original in the collection of Mel Gulotta who found the specimen. Locality, horizon, and age – Holotype found in a bluff along the Pamunkey River upriver from U. S. Highway 301, Hanover County, Virginia; basal Piscataway Member of the Aquia Formation; late Paleocene (early Thanetian). Referred specimen found in the Blue Banks south of Liverpool Point, Charles County, Maryland; “ Zone 2, ” Piscataway Member, Aquia Formation (Clark and Martin 1901); late Paleocene (early Thanetian).	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFBDFFE2FF64F91CFD2DFAB2.taxon	description	Description – Cranium slightly longer than wide, snout narrow but rounded and not elongate. Dorsally, parietals cover nearly half of the skull roof; supraoccipital does not extend beyond the parietals as far rearward as the squamosal horns. Ventrally, a secondary palate is well developed, with both narrow premaxillaries and vomer elongated back to half way across the suborbital vacuities and with maxillary-palatine flanges extending even farther back to either side and terminating in a small contribution to the palate by the pterygoids.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFBDFFE2FF64F91CFD2DFAB2.taxon	discussion	Remarks – The species Osteopygis roundsi was described by Weems (1988) and assigned to the genus Osteopygis. Since then, Parham (2005) has established that the concept of O. emarginatus had become a chimera with a pancheloniid skull improperly associated with a “ macrobaenid ” shell and skeleton. He concluded that the postcranial material should remain O. emarginatus but that the skull should be assigned to Euclastes wielandi. Thus, the holotype skull of “ O. ” roundsi was referred to Euclastes (Lynch and Parham 2003). The paratype postcranial shell elements of E. roundsi now are referred to Judithemys kranzi n. sp. The excellent skull cast of E. roundsi illustrated here (Figs. 14 D-H) was made by Billy Palmer for the Calvert Marine Museum. The suture boundaries of the skull elements can be readily seen on both the original and the cast (Figs. 15 A, B). This specimen, by far the best example of this species yet found, differs considerably from the holotype (Fig. 15 E) in that the nasals and vomer of the new specimen are much narrower than in the holotype, the contribution of the pterygoids to the secondary palate is smaller, and the vomer lacks a strong midline ridge. This perhaps could indicate that two durophagous pancheloniid species are present in the Aquia, but both skulls are almost identical in absolute size and ecologically it seems very unlikely for two closely related species to be present in the same area at essentially the same time. With only two skulls of E. roundsi available for study, it is impossible to determine the range of individual variability that existed in the secondary palates of these turtles. However, it is significant that Zangerl (1971) described considerable differences in skulls of the closely related turtle Erquelinnesia gosseleti (Dollo 1886) and suggested that these differences may reflect sexual dimorphism similar to that seen in the modern alligator snapping turtle (Macrochelys temmincki (Troost in Harlan 1835). Therefore it seems best to consider the two available skulls of E. roundsi from the Aquia Formation as examples of a single species with a markedly variable palate region, possibly due to sexual dimorphism but otherwise with the same skull morphology. The secondary palate of both specimens of E. roundsi are much longer than the secondary palate of E. wielandi (Fig. 15), and the premaxillaries and vomer also are much longer and narrower than in E. wielandi. These consistent and marked differences between the length of the palate region and constituent bones of E. wielandi and E. roundsi refutes the suggestion by Lynch and Parham (2003) and Parham and Pyenson (2010) that these two species are synonymous, though in all likelihood E. roundsi descended from E. wielandi. The secondary palate of the slightly younger (late Thanetian) species E. platyops Cope 1867 is much wider than in E. roundsi, and E. platyops also seems to have attained a much larger size. The palate of E. gosseleti is more similar to E. roundsi in its size and proportions than the palates of the other described species, but a striking difference is that the palatines of E. gosseleti enclose the vomer posteriorly unlike in any of the other species (Parham 2005, fig. 3). No carapace material referable to Euclastes has been identified so far from the Aquia Formation, but it would presumably be similar to the carapace of the closely related turtle E. gosseleti (Fig. 16).	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFBDFFECFF11FD36FE90F90F.taxon	description	Specimen – USNM 412113, palate composed of premaxillaries, maxillaries, and vomer, described in Weems (1988). Locality, horizon, and age – Found at Hampton Mall, Prince Georges County, Maryland; Brightseat Formation; early Paleocene (Danian).	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFBDFFECFF11FD36FE90F90F.taxon	discussion	Remarks – A pair of fused premaxillaries and maxillaries from the Brightseat Formation in Prince Georges County, Maryland were assigned by Weems (1988) to Osteopygis emarginatus following the taxonomy current at that time. Since then, Parham (2005) has demonstrated that only carapace and plastral material assigned to O. emarginatus properly belongs to that taxon, which belongs in the “ Macrobaenidae. ” Skull material that had been assigned to O. emarginatus does not belong to that species and instead belongs to a pancheloniid turtle, Euclastes wielandi. Therefore, the Brightseat skull fragment has been taxonomically reassigned to E. wielandi and the Pancheloniidae.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFB3FFE2FF51FABCFA57F9D3.taxon	description	Specimen – USNM 358865, disarticulated partial skeleton consisting of the fused dentaries, nuchal, right and left first peripherals, right and left second peripherals, right third peripheral, fifth, sixth and ninth left peripherals, eleventh right peripheral, parts of second costal, sixth right costal, first neural, part of fourth neural, eighth neural, and first suprapygal, described in Weems (1988). Locality, horizon, and age – West bank of roadcut, Indian Head Road near Piscataway Creek, Prince Georges County, Maryland; Piscataway Member of the Aquia Formation; late Paleocene (early Thanetian).	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFB3FFE2FF51FABCFA57F9D3.taxon	discussion	Remarks – The turtle described by Weems (1988) as Catapleura ruhoffi later was discussed by Tong and Hirayama (2002), who strongly implied but did not explicitly state that the species should be referred to the genus Tasbacka. The first costal of T. ruhoffi is quite similar to that of Catapleura in that its external border is much longer than its internal border. This is due to the fact that the sutures along the anterior border of the first costals are strongly angled outward from the rim of the shell carapace (away from the midline) and not oriented normal to the carapace rim as is typical in pancheloniid turtles. This unusual conformation was why Weems (1988) referred the species to that genus. However, it is now apparent that in this regard the first costal of T. ruhoffi also is very similar to that of Tasbacka, and in all other diagnosable characters the similarity with Tasbacka is greater. Therefore, assignment to Tasbacka is accepted here. Tong and Hirayama (2002) correctly reported the age and stratigraphic horizon of T. ruhoffi, but they erroneously placed the type locality in the “ Pamunkie [Pamunkey] River Bluffs, Virginia; ” the type specimen actually is from Prince Georges County, Maryland. Tong and Hirayama (2002) thought that, in characters that can be compared between the two taxa, T. ruhoffi is very similar to T. aldabergeni except that T. aldabergeni has a more strongly developed symphyseal ridge on its dentary (Nessov 1987). It is also true, however, that the nuchal of T. aldabergeni has a much shallower anterior concavity (width: depth ratio = 14) than the nuchal of T. ruhoffi (width: depth ratio = 7), and the seventh to ninth neurals of T. ruhoffi are keeled while the seventh to ninth neurals of T. aldabergeni are unkeeled (compare fig. 2 of Nessov 1987 with fig. 18 of Weems, 1988). Therefore, even though both species are referable to Tasbacka, they appear to be distinctly different. T. aldabergeni was described from the late Paleocene of Kazakhstan and a third species, T. ouledabdounensis Tong and Hirayama 2002 has been described from the late Paleocene of Morocco (Tong and Hirayama 2002), so Tasbacka seems to have dispersed widely in the early or middle Paleocene and then developed into distinctly different populations in central Asia, north Africa, and the eastern United States. It seems likely that some population of late Paleocene Tasbacka was the ancestor of the early Eocene species Puppigerus camperi (Gray) Moody.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFB3FFE3FDB7F91BFB59FB4A.taxon	description	(Figs. 17 A – F) Specimens — CMM-V- 4769, proximal and central part of fourth right costal found by Bob Wiest; CMM- V- 4770; right premaxillary found by Bob Wiest; CMM- V- 4771, fragmentary nuchal found by Gary Grimsley; CMM-V- 3322, fragmentary nuchal found by Bill Counterman; CMM-V- 4773, central and distal portion of right hyoplastron found by George Fonger. Locality, horizon, and age — All found in the bluff immediately west of Loyola Retreat, 1.7 miles north of Popes Creek, Charles County, Maryland; lower part (Bed A) of the Woodstock Member, Nanjemoy Formation; early Eocene (Ypresian) within nannoplankton zone NP 12. Description — Hyoplastron wide with a long external border extending far anteriorly but lacking any sutural border with the carapace, costals thin and lacking external sculpture, premaxillary forms narrow forward snout with a well-developed secondary palate.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFB3FFE3FDB7F91BFB59FB4A.taxon	discussion	Remarks — These remains and others of similar size are the most commonly found fragments of turtle in the Woodstock Member of the Nanjemoy; they are found in both the lower and upper beds A and B. They are not perceptibly different in size or morphology from skeletal material of Puppigerus camperi described and illustrated by Moody (1974) from the London Clay, which is equivalent in age to the Nanjemoy. This species has been reported from the lower member of the Nanjemoy, based on fused elongate dentaries with a prominent shelf (Weems 1999), so it is not surprising to find it in the upper member as well. Curiously, although Eosphargis and Puppigerus are found both in the Nanjemoy Formation and the London Clay, other London Clay marine turtles (Neurochelys Moody 1980, Argillochelys Lydekker 1889 a and Eochelone Dollo 1903, Moody 1996, Lapparent de Broin 2001) have not been found in the Nanjemoy.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFB2FFE0FD9FFAD3FB0FF9AB.taxon	description	Specimen — CMM-V- 4781, costal found by Robert E. Weems. Locality, horizon, and age — Found in place about a foot above the basal contact at the base of the low bluff outcrop at Northbury, northwestern New Kent County, Virginia on the south bank of the Pamunkey River; Old Church Formation; late early Oligocene (late Rupelian, lower nannofossil zone NP 24). Description — Distal two-thirds of a costal element lacking any trace of surface sculpturing.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFB2FFE0FD9FFAD3FB0FF9AB.taxon	discussion	Remarks — This costal is quite similar in its proportions to the costals of Procolpochelys charlestonensis, known from the early Chattian Chandler Bridge Formation near Charleston, South Carolina. The Old Church specimen is smaller than the type of P. charlestonensis and relatively somewhat thinner, but this is typical of juvenile specimens of Procolpochelys. The absence of sculpturing precludes assignment to Ashleychelys Weems & Sanders 2014 or Carolinochelys Hay 1923 which are the only other pancheloniid genera known from the Oligocene of South Carolina. The presence of a juvenile P. charlestonensis in Virginia supports the suggestion of Weems and Sanders (2014) that Procolpochelys nested north of the Charleston, South Carolina region, because only adult specimens have been found in the Charleston area.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFB1FFE1FDFFF995FE82FDB6.taxon	description	Locality, horizon, and age — Found on the beach at the base of the low bluff outcrop at Northbury, northwestern New Kent County, Virginia on the south bank of the Pamunkey River; Old Church Formation; late early Oligocene (late Rupelian, nannofossil zone NP 24). Along this part of the bluff, only the Old Church is exposed. Description — Narrow hexagonal-shaped neural with a low longitudinal keel and sculpturing typical of Ashleychelys.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFB1FFE1FDFFF995FE82FDB6.taxon	discussion	Remarks — This isolated neural is quite similar in shape, size, thickness and pattern of sculpturing to neurals of Ashleychelys palmeri, known from the Late Rupelian Ashley and early Chattian Chandler Bridge formations near Charleston, South Carolina. The elongate shape, low longitudinal keel, and characteristic sculpturing are typical of Ashleychelys.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFB0FFE1FEA4FD80FD12FAE7.taxon	description	(Figs. 18 C – D) Specimen — CMM-V- 4783, neural found by Ron Ison; CMM-V- 4784, neural found by Jason Osborne. Locality, horizon, and age — Along the banks of the Pamunkey River where it forms the boundary between New Kent and King William counties, Virginia; Old Church Formation; late early Oligocene (late Rupelian, lower nannofossil zone NP 24). Description — Neurals hexagonal in shape, flat and without a medial longitudinal keel, bearing sculpture characteristic of Carolinochelys.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
1160879CFFB0FFE1FEA4FD80FD12FAE7.taxon	discussion	Remarks — These isolated neurals are quite similar in shape, size, thickness and pattern of sculpturing to neurals of Carolinochelys wilsoni, known from the Late Rupelian Ashley and early Chattian Chandler Bridge formations near Charleston, South Carolina. The lack of a medial longitudinal keel precludes their assignment to Ashleychelys, which has a somewhat different pattern of sculpturing, and their hexagonal shape and the presence of sculpturing precludes assignment to Procolpochelys.	en	Robert, Weems, E. (2014): Paleogene chelonians from Maryland and Virginia. PaleoBios 31 (1): 1-32
