Reconstruction of Metoposaurus krasiejowensis, copyright Dmitry Bogdanov.

Belongs within: Stereospondylomorpha.

The Trematosauria are a clade of temnospondyls defined by Yates & Warren (2000) as including all species closer to Trematosaurus than Parotosuchus.

Synapomorphies (from Yates & Warren 2000): Interorbital space greater than 50% of skull width at mid orbital level; stapedial foramen absent; sharp rimmed depressions absent at posterior end of ventral surface of parasphenoid plate; denticle patches absent from all three coronoids; chorda tympanic foramen located on preaticular; hamate process absent.

<==Trematosauria [Trematosauroidei] YW00
    |  i. s.: Lyrocephalus euri CZ79
    |–+–Luzocephalus YW00
    |  `–Trematosauroidea YW00
    |       |–Thoosuchus jakovlevi YW00
    |       `–Lyrocephaliscus [Trematosauridae] YW00
    |            `–L. euri YW00
    `–+–Metoposauroidea YW00
       |    |–Almasaurus habbazi Dutuit 1972 YW00, CZ79
       |    |–Buettneria perfecta YW00
       |    |–Apachesaurus PI05
       |    `–Metoposaurus Lydekker 1890 D07
       |         |–M. bakeri D07
       |         |–M. diagnosticus YW00
       |         |–M. heimi D07
       |         |–M. krasiejowensis D07
       |         |–M. maleriensis DDL04
       |         |–M. santaecrucis D07
       |         `–M. stuttgartiensis D07
       `–+–Plagiosauroidea YW00
          |    |–Laidleria [Laidleriidae] YW00
          |    |    `–L. gracilis Kitching 1958 CZ79
          |    `–Plagiosauridae YW00
          |         |–Plagiosternum danilovi YW00
          |         `–Plagiosaurus YW00
          `–+–Brachyopoidea YW00
             |    |–Keratobrachyops australis YW00
             |    `–+–Brachyopidae YW00
             |       |    |–Xenobrachyops allos YW00
             |       |    |–Brachyops laticeps S87
             |       |    `–Batrachosuchus YW00
             |       |         `–‘Blinasaurus’ henwoodi YW00
             |       `–Chigutisauridae YW00
             |            |–Siderops kehli YW00
             |            `–Pelorocephalus Cabera 1944 YW00, D07 [incl. Chigutisaurus YW00]
             |                 |–P. cacheutensis D07
             |                 |–P. ischigualastensis D07
             |                 |–P. mendozensis D07
             |                 `–P. tenax D07
             `–Rhytidosteoidea CZ79
                  |–Indobrachyopidae CZ79
                  |    |–Derwentia warreni Cosgriff 1974 CZ79
                  |    `–+–Indobrachyops panchetensis Van Huene & Sahni 1958 CZ79
                  |       `–+–Rewana quadricuneata Howie 1972 CZ79
                  |          `–Mahavisaurus CZ79
                  |               |–M. australis (Lehmann 1966) [=Lyrosaurus australis] CZ79
                  |               `–M. dentatus Lehmann 1966 CZ79
                  `–Rhytidosteidae YW00
                       |  i. s.: Arcadia myriadens YW00
                       |         Trucheosaurus YW00
                       |–Deltasaurus CZ79
                       |    |–D. kimberleyensis Cosgriff 1965 CZ79
                       |    `–D. pustulatus Cosgriff 1965 CZ79
                       `–+–Pneumatostega Cosgriff & Zawiskie 1979 CZ79
                          |    `–*P. potamia Cosgriff & Zawiskie 1979 CZ79
                          `–+–Rhytidosteus capensis Owen 1884 CZ79
                             `–Peltostega CZ79
                                  |–P. erici Wiman 1916 CZ79
                                  `–P. wimani Nilsson 1946 CZ79

*Type species of generic name indicated


[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.

[DDL04] Datta, P. M., D. P. Das & Z.-X. Luo. 2004. A Late Triassic dromatheriid (Synapsida: Cynodontia) from India. Annals of Carnegie Museum 73 (2): 12–24.

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

[PI05] Parker, W. G., R. B. Irmis, S. J. Nesbitt, J. W. Martz & L. S. Browne. 2005. The Late Triassic pseudosuchian Revueltosaurus callenderi and its implications for the diversity of early ornithischian dinosaurs. Proceedings of the Royal Society of London Series B—Biological Sciences 272: 963–969.

[S87] Stephens, W. J. 1887. On the Biloela labyrinthodont (second notice). Proceedings of the Linnean Society of New South Wales, series 2, 1 (4): 1113–1121, pl. 14.

[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.

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