taxonID	type	description	language	source
0634C846C50CE5314EBDF88EFB61FADE.taxon	description	In his treatments of Triadobatrachus (as “ Protobatrachus ”), Pivetaeau (1936 a, 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. 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.	en	Gardner, James D. (2016): The Fossil Record Of Tadpoles. Fossil Imprint 72 (1 - 2): 17-44, DOI: 10.14446/FI.2016.17
0634C846C50EE52F4E9DFA14FD68FD83.taxon	description	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). 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.	en	Gardner, James D. (2016): The Fossil Record Of Tadpoles. Fossil Imprint 72 (1 - 2): 17-44, DOI: 10.14446/FI.2016.17
