identifier	taxonID	type	CVterm	format	language	title	description	additionalInformationURL	UsageTerms	rights	Owner	contributor	creator	bibliographicCitation
0634C846C50CE5314EBDF88EFB61FADE.text	0634C846C50CE5314EBDF88EFB61FADE.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Triadobatrachus massinoti (PIVETEAU 1936) Salientia	<div><p>Triadobatrachus massinoti (PIVETEAU, 1936a) from the Early Triassic of Madagascar</p> <p>The most iconic of the purported tadpole fossils is the holotype and only known specimen of the basal salientian Triadobatrachus massinoti; note the original generic name “ Protobatrachus ” was amended by Kuhn (1962). Triadobatrachus is from the Early Triassic of Madagascar and it is the geologically oldest lissamphibian fossil. The holotype is challenging to interpret because (1) it consists of an incomplete skeleton, missing the anterior end of the snout and most of the hands and feet, and is of moderate size (preserved midline length of about 9 cm), (2) the skeleton is preserved as natural molds or impressions exposed in dorsal and ventral aspect on two halves of a split nodule (Text-fig. 2 a–d), and (3) it exhibits a mixture of primitive and derived characters. Although its relevance to the evolutionary history of anurans once was a source of debate (e.g., see historical summaries and discussions by Hecht 1962, Griffiths 1963, Estes and Reig 1973, Roček and Rage 2000b, Rage 2006, and references therein), Triadobatrachus now is widely regarded as the sister to all other salientians (e.g., Ford and Cannatella 1993, Báez and Basso 1996, Evans and Borsuk-Białynicka 1998, Rage 2006, Anderson 2007, Marjanović and Laurin 2014, Ascarrunz et al. 2016). The ontogenetic age of the holotype of Triadobatrachus also has been debated.</p> <p>In his treatments of Triadobatrachus (as “ Protobatrachus ”), Pivetaeau (1936a, b, 1937, 1955) regarded the holotype skeleton as being from an adult animal. That remained the conventional wisdom until challenged by Griffiths (1956, 1963), who proposed that the holotype was “a tadpole in the later stages of metamorphosis” (Griffiths 1956: 343). In support of that larval interpretation, Griffiths (1963: 275–276) listed the following postcranial and cranial features: tail present, consisting of small vertebrae; no anuran-style sacrum (i.e., lacks diapophyses that are laterally directed, expanded, and incorporate fused sacral ribs); iliac shaft only moderately elongate anteriorly; radius and ulna in forelimbs and tibia and fibula in hindlimbs unfused; femur considerably longer than tibia and fibula; upper jaw elements absent; lower jaw bones weakly sutured; and parietal recess present along midline of the paired frontoparietals. In the latter paper, Griffiths (1963: 276–277) also argued for an aquatic origin for salientians and, under that scenario, softened his stance on the ontogenetic age of the holotype of T. massinoti by admitting it could be either a larva or an adult. Orton (1957: 80) quickly embraced Griffiths’ (1956) larval interpretation, calling it “an illuminating idea which can account for virtually all of the peculiarities of the specimen”. Hecht (1962: 43) disagreed by saying “the interpretation of Protobatrachus as a tadpole, is considered unlikely due to the well-ossified nature of the fossil.” Perplexingly, but perhaps understandable given his staunch view that Triadobatrachus had nothing to do with the evolution of anurans, Tihen (1965: 309–310) dismissed the debate about the ontogenetic age of the holotype by stating “Whether it is a late stage larval or metamorphic individual … or an adult … is not of major import”. Despite their detailed examination and reconsideration of the holotype of T. massinoti, Estes and Reig (1973) could offer only vague comments about its ontogenetic age, such as “[it was] probably a young stage” (p. 42) and “It may represent a young stage but is probably not far from adult” (p. 49). Their statement that its “interpretation as adult or larva … has not been satisfactorily resolved” (Estes and Reig 1973: 49) was a fair assessment of the situation at the time and remained so for over a decade to come.</p> <p>Rage and Roček (1986: 257, 1989: 13) argued that the holotype of T. massinoti was from a postmetamorphic individual because it has fully developed dermal skull bones, a columella of adult size, ossified carpal and tarsal elements, and presumably both an ossified parahyoid and thyrohyals; note the presence of those hyoid bones recently was corroborated by a micro-CT study of the holotype by Ascarrunz et al. (2016: fig. 4). Rage and Roček (1986: 257, 1989: 13) also disputed the cranial features listed by Griffiths (1956, 1963) by (1) dismissing the weakly sutured lower jaw bones as equivocal evidence for Triadobatrachus being a larva, (2) identifying the posterior ends of both maxillae, thereby showing that at least some upper jaw bones were present (Rage and Roček 1989: fig. 2; see also Ascarrunz et al. 2016: fig. 4), and (3) re-interpreting the “parietal recess” of Griffiths (1963: 276) simply as part of the indistinct, dorsal ornament on the frontoparietals. As for the suite of postcranial features listed by Griffiths (1956, 1963), Rage and Roček (1989: 13) countered that those only need be considered larval features if one assumes – as Griffiths implicitly appeared to have done – that Triadobatrachus was a primitive anuran. In that interpretation, had the holotype individual lived longer it would have undergone metamorphosis, during which its “larval” features would have transformed into features characteristic of adult or fully metamorphosed anurans. For example, the tail would be lost as the caudal vertebrae fused to form a urostyle, the iliac shaft would grow farther anteriorly, and the radius and ulna would fuse to form a composite radioulna. The alternate interpretation, favored by Rage and Roček (1986, 1989) and tacitly accepted since, is that the postcranial features listed by Griffiths (1956, 1963) are not larval features, but instead are plesiomorphies indicative of Triadobatrachus being a basal salientian. Rage and Roček (1989: 13) concluded that the holotype of T. massinoti was a postmetamorphic individual, although they noted that the unossified epiphyses of its long bones indicated it likely died before reaching full maturity. The recent micro-CT study by Ascarrunz et al. (2016) revealed no features at odds with the interpretation that the holotype skeleton T. massinoti is from a postmetamorphic individual.</p> </div>	https://treatment.plazi.org/id/0634C846C50CE5314EBDF88EFB61FADE	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	Gardner, James D.	Gardner, James D. (2016): The Fossil Record Of Tadpoles. Fossil Imprint 72 (1 - 2): 17-44, DOI: 10.14446/FI.2016.17
0634C846C50EE52F4E9DFA14FD68FD83.text	0634C846C50EE52F4E9DFA14FD68FD83.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Palaeospondylus gunni TRAQUAIR 1890	<div><p>Palaeospondylus gunni TRAQUAIR, 1890 from the Middle Devonian of Scotland and a “tadpole” from the Early Cretaceous of Israel</p> <p>Two kinds of small-bodied, moderately elongate, aquatic, and larval-like fossils have been regarded as possible tadpoles. The first of these is Palaeospondylus gunni TRAQUAIR, 1890, an enigmatic fish-like vertebrate known from hundreds of articulated skeletons, none longer than about 60 mm (Text-fig. 2e). Most examples of this fossil originate from the Achanarras Quarry in the Highlands of Scotland, a Middle Devonian locality that has yielded abundant specimens belonging to about 16 species of jawless and jawed fish (e.g., Trewin 1986, Johanson et al. 2011). Despite being known by hundreds of articulated skeletons, Palaeospondylus has proven challenging to study and interpret because all the specimens are small and most are flattened or crushed. Since its discovery, the identity of Palaeospondylus has been controversial: at various times it has been regarded either as a larva or an adult, and it has been referred to most major groups of fish (see historical summaries by Moy-Thomas 1940, Forey and Gardiner 1981, Thomson 1992, 2004, Johanson et al. 2010, Janvier and Sanson 2016).</p> <p>Palaeospondylus twice has been interpreted as a tadpole-like organism. In their brief treatments of Palaeospondylus, Dawson (1893: 186) stated “I should not be surprised if it should come to be regarded either as a forerunner of the Batrachians or as a primitive tadpole”, while nearly a century later Jarvik (1980: 218) suggested “ Palaeospondylus may be related to the anurans”. Although Jarvik (1980: 218) went on to suggest that Palaeospondylus might also be a larval osteolepiform fish, most of his short discussion on the identity of Palaeospondylus focused on comparing it to extant and fossil tadpoles, and also to a problematic fossil discussed below from the Early Cretaceous of Israel. Jarvik (1980: 218) cited two morphological similarities between Palaeospondylus and bonafide tadpoles: 1) ring-shaped vertebrae and 2) the external shape of the tail. He bolstered that comparison by including side-by-side drawings of a Palaeospondylus skeleton and a Recent anuran tadpole depicted at the same size and in virtually identical poses (Jarvik 1980: fig. 153). Forey and Gardiner (1981: 136) countered that neither of the features cited by Jarvik (1980) are unique to tadpoles and, thus, are hardly convincing for regarding Palaeospondylus as a tadpole. There also are significant osteological differences between Palaeospondylus and tadpoles. For example, the cranium and branchial skeleton in Palaeospondylus are unlike those of tadpoles (cf. Forey and Gardiner 1981: fig. 1 versus Duellman and Trueb 1986: figs 6-6D, E, 6-7B). Further, as was alluded to by Moy-Thomas (1940: 407), whereas the caudal fin in Palaeospondylus is supported internally by a series of well-developed, bifurcating radials (see Text-fig. 2e), the caudal fin in tadpoles is a soft structure that lacks any internal supports (cf. Moy-Thomas 1940: text-fig. 6, pl. 25 versus Wassersug 1989: fig. 1). The only resemblances between Palaeospondylus and tadpoles are those common to aquatic, larval vertebrates in general: small size; elongate form; tail present and bearing dorsal and ventral fins; simple axial skeleton; and rudimentary girdles and appendages.</p> <p>Although clearly not a tadpole, the affinities of Palaespondylus remain elusive. Work from the 1980s onwards has viewed Palaespondylus as a larval fish. Forey and Gardiner (1981) revived the idea that Palaespondylus was a larval lungfish, an idea that later received support from Thomson et al. (2003; see also Thomson 2004), who proposed that the co-occuring lungfish Dipterus valenciennesi SEDGWICK et MURCHISON, 1829 likely was the adult form. The larval lungfish hypothesis has been contradicted by the subsequent discovery of a small Dipterus fossil at the Achanarras Quarry that falls within the size range of Palaespondylus, but is morphologically distinct in possessing well-developed tooth plates (Newman and Blaauwen 2008), and by developmental work that showed Palaespondylus possesses a suite of features not seen in larval lungfish and also lacks features expected for larval lungfish (Joss and Johanson 2007). Recent histological studies revealed a novel skeletal tissue unique to Palaespondylus and suggest its affinities lie within the osteichthyians or bony fishes (Johanson et al. 2010, 2011). Most recently, Janvier and Sanson (2016) revived the idea that Palaespondylus might be related to hagfishes by noting general resemblances between the two taxa, although they admitted there are no obvious synapomorphies to support that relationship.</p> <p>A superficially Palaespondylus -like fossil from the Early Cretaceous (Aptian) of Israel also has been interpreted as a tadpole. The fossil was collected from the same locality (Amphibian Hill, at Makhtesh Ramon) that yielded over 200 metamorphosed anuran skeletons of the basal pipimorphs Thoraciliacus rostriceps and Cordicephalus gracilis (e.g., Nevo 1968, Trueb 1999, Roček 2000, Trueb and Báez 2006, Gardner and Rage 2016) and a dozen tadpole body fossils referable to Thoraciliacus (Roček and Van Dijk 2006). The fossil was described and figured twice as a tadpole by Eviatar Nevo: first briefly in his short paper announcing the discovery of frog fossils at Makhtesh Ramon (Nevo 1956: 1192, fig. 2) and then in more detail in his unpublished PhD thesis (Nevo 1964: 36–37, 106–108, pl. VII). Nevo (1964: 36) also mentioned that Makhtesh Ramon had yielded three additional tadpole fossils (all larger and presumably representing later ontogenetic stages), but he did not describe or discuss those further; presumably those three larger specimens were among the 12 bonafide tadpoles described by Roček and Van Dijk (2006) in their ontogenetic study of Cretaceous pipimorphs. Curiously, in his subsequent monographic treatment of anurans from Makhtesh Ramon, Nevo (1968: 258) only mentioned “one tadpole”. Based on Nevo’s (1956) paper, later workers generally accepted his tadpole identification (e.g., Hecht 1963: 22, Griffiths 1963: 282, Špinar 1972: 164, Jarvik 1980: 218, Metz 1983: 63) and, until the description of the older (Hauterivian or Barremian) size series of Shomronella tadpoles by Estes et al. (1978), the Makhtesh Ramon fossil was regarded as the geologically oldest tadpole fossil. Only Estes et al. (1978: 375) questioned whether the fossil was a tadpole, but they did not discuss it further. This Palaespondylus -like specimen was not among the 12 bonafide tadpole fossils from Makhtesh Ramon that were available for Roček and Van Dijk’s (2006) ontogenetic study (Z. Roček, pers. comm. 2016).</p> <p>Based on Nevo’s (1964) more detailed description, the purported tadpole fossil from Makhtesh Ramon is about 33 mm long. According to Nevo (1964: 36) the specimen “is preserved as a brown limonitic cast and imprint. It consists of a well demarcated head and a long body and tail.” Nevo (1964) described the head as roughly rectangular in outline and interpreted in it a number of tadpole-like cranial features, most notably azygous frontoparietals and a sword-like parasphenoid, large otic capsules, a possible spiracle, and possible imprints of a slightly detached beak. A series of small vertebrae extends along the axial column to the end of the tail, and the tail bears what appears to be an anteroposteriorly short, heterocercal caudal fin without any obvious indication of internal supports. No traces of limbs or girdles were reported. Nevo (1964: 107) tentatively suggested the fossil might be a tadpole of the co-occuring anuran Thoraciliacus. Jarvik (1980: 218) explicitly compared the Makhtesh Ramon fossil to Palaespondylus, and used that comparison to bolster his suggestion that the latter was tadpole. Based on figures published by Nevo (1956, 1964) and setting aside his interpretations of its structure, on the basis of its general structure and proportions the Makhtesh Ramon fossil seems more reminiscent of Palaespondylus than of tadpoles, including tadpoles of Thoraciliacus described from Makhtesh Ramon by Roček and Van Dijk (2003). Intriguingly, however, no fish fossils have been reported from Makhtesh Ramon (see Database of Verte-brates: Fossil Fish, Amphibians, Reptiles, Birds (fosFARbase) at www.wahre-staerke.com; accessed 15 May 2016). Another possibility is that the Israeli specimen might be a young larval individual of the salamander Ramonellus longispinus NEVO et ESTES, 1969, which is known at Makhtesh Ramon by about 16 presumably adult skeletons (e.g., Nevo and Estes 1969, Estes 1981, Gardner et al. 2003, Gardner and Rage 2016). More detailed study of this intriguing Early Cretaceous, tadpole-like fossil is needed to resolve its identity.</p> </div>	https://treatment.plazi.org/id/0634C846C50EE52F4E9DFA14FD68FD83	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	Gardner, James D.	Gardner, James D. (2016): The Fossil Record Of Tadpoles. Fossil Imprint 72 (1 - 2): 17-44, DOI: 10.14446/FI.2016.17
