Temnospondyli

Reconstruction of Dendrerpeton, from here.


Belongs within: Neostegalia.
Contains: Stereospondylomorpha, Dissorophoidea.

The Temnospondyli were one of the most significant early clades of amphibian-grade tetrapods, being recorded from the early Carboniferous (Visean) to the mid-Cretaceous (Albian). Whether they survived after this date depends on whether the modern amphibians (particularly frogs and salamanders) are accepted as derived temnospondyls. The clade as a whole is characterised by the presence of interpterygoid vacuities at least half as wide as the skull and bordered by triradiate pterygoids (Ruta et al. 2003). The majority of temnospondyls were semiaquatic, though the clade as a whole includes members varying from almost entirely terrestrial to fully aquatic.

Early Carboniferous temnospondyls include the Scottish Balanerpeton and the Nova Scotian Dendrerpeton, both medium-sized semi-terrestrial forms with the latter reaching about a metre in length. The Late Carboniferous and Early Permian Cochleosauridae were crocodile-like semi-aquatic ambush predators, reaching lengths of over 1.5 m. The Early Permian saw the appearance of even larger forms: Edops craigi reached about two metres in length, whereas the three metre-long Eryops megacephalus was one of the largest land animals of its time. Eryops had a more strongly build appendicular skeleton than other temnospondyls, indicating a greater degree of adaptation for terrestrial locomotion.

Temnospondyli [Euskelia]
    |--+--+--Edops [Edopidae, Edopoidea] PS17
    |  |  |    `--E. craigi Romer 1935 RCQ03
    |  |  `--Cochleosauridae RCQ03
    |  |       |--Chenoprosopus lewisi Hook 1993 RCQ03
    |  |       `--Cochleosaurus Fritsch 1885 D07
    |  |            |--C. bohemicus D07
    |  |            `--C. florensis Rieppel 1980 RCQ03
    |  `--Eryopoidea YW00
    |       |--Zatrachydidae YW00
    |       `--Eryopidae RCQ03
    |            |--Onchiodon YW00
    |            `--Eryops Miner 1925 PS17, D07
    |                 `--E. megacephalus Cope 1877 RCQ03
    `--+--+--Balanerpeton woodi Milner & Sequeira 1994 PS17, RCQ03
       |  `--Dendrerpeton [Dendrerpetontidae] PS17
       |       |--D. acadianum Owen 1853 RCQ03
       |       `--D. helogenes YW00
       `--Dissorophoidea PS17

Temnospondyli incertae sedis:
  Adamanterpeton ohioensis RCQ03
  Cacops Williston 1910 D07
    `--C. aspideporus D07
  Kamacops S02
  Cyclotosaurus PS88 [incl. Procyclotosaurus W70]
  Laccosaurus PS88
  Platyhystrix Berman, Reisz & Fracasso 1981 D07
    `--P. rugosus D07
  Gerrothorax Nilsson 1937 D07
    |--G. pulcherrimus D07
    `--G. rhaeticus D07
  Latiscopus [Latiscopidae] CZ79
    `--L. disjunctus Wilson 1948 CZ79
  Limnarchia [Dvinosauroidea] RCQ03
    |  i. s.: Erpetosaurus PS88
    |--Stereospondylomorpha YW00
    `--Dvinosauria YW00
         |  i. s.: Eugyrinus YW00
         |--Trimerorhachidae [Trimerorhachoidea] RCQ03
         |    |--Neldasaurus wrightae Chase 1965 YW00, RCQ03
         |    `--Trimerorhachis insignis Case 1935 YW00, RCQ03
         `--Dvinosauroidea YW00
              |--Eobrachyopidae YW00
              |    |--Isodectes obtusus (Cope 1868) YW00, RCQ03 (see below for synonymy)
              |    `--Acroplous vorax YW00
              `--+--Tupilakosaurus [Tupilakosauridae] YW00
                 `--Dvinosaurus [Dvinosauridae] YW00
                      |--*D. primus Amalitskii 1921 YW00, TT05
                      `--D. egregius YW00

Isodectes obtusus (Cope 1868) YW00, RCQ03 [=Saurerpeton obtusum YW00; incl. I. megalops YW00]

*Type species of generic name indicated

REFERENCES

[CZ79] Cosgriff, J. W., & J. M. Zawiskie. 1979. A new species of the Rhytidosteidae from the Lystrosaurus Zone and a review of the Rhytidosteoidea. Palaeontologia Africana 22: 1–27.

[D07] Dixon, D. 2007. The Complete Illustrated Encyclopedia of Dinosaurs & Prehistoric Creatures. Hermes House: London.

[PS88] Panchen, A. L., & T. R. Smithson. 1988. The relationships of the earliest tetrapods. In: Benton, M. J. (ed.) The Phylogeny and Classification of the Tetrapods vol. 1. Amphibians, Reptiles, Birds pp. 1–32. Clarendon Press: Oxford.

[PS17] Pardo, J. D., M. Szostakiwskyj, P. E. Ahlberg & J. S. Anderson. 2017. Hidden morphological diversity among early tetrapods. Nature 546: 642–645.

[RCQ03] Ruta, M., M. I. Coates & D. L. J. Quicke. 2003. Early tetrapod relationships revisited. Biological Reviews 78: 251–345.

[S02] Schoch, R. R. 2002. The neurocranium of the stereospondyl Mastodonsaurus giganteus. Palaeontology 45 (3): 627–645.

[TT05] Tverdokhlebov, V. P., G. I. Tverdokhlebova, A. V. Minikh, M. V. Surkov & M. J. Benton. 2005. Upper Permian vertebrates and their sedimentological context in the South Urals, Russia. Earth-Science Reviews 69: 27–77.

[W70] Wills, L. J. 1970. The Triassic succession in the central Midlands in its regional setting. Quarterly Journal of the Geological Society of London 126: 225–283.

[YW00] Yates, A. M., & A. A. Warren. 2000. The phylogeny of the ‘higher’ temnospondyls (Vertebrata: Choanata) and its implications for the monophyly and origins of the Stereospondyli. Zoological Journal of the Linnean Society 128: 77–121.

Last updated: 3 August 2017.

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