Largocephalosaurus and Omphalosaurus

Vertebrata

Fish

Tetrapoda

Reptilia/Amniota

Archosauromorpha

Basal Archosauromorpha

Terrestrial Younginiformes

Marine Younginiformes

Lepidosauromorpha

Cephalerpeton clade

Captorhinidae

Milleretta Limnoscelis clade

Bolosaurus Diadectes clade

Turtle Pareiasaur clade

Fenestrasauria • Pterosauria

Protosquamata

Squamata

Largocephalosaurus polycarpon (Cheng et al. 2012) was described as a basal eosauropterygian from the Middle Triassic. Unfortunately their analysis did not include Sinosaurosphargis, which it most closely resembled.

Largocephalosaurus qianensis (Li et al. 2013) is a new and more complete species more primitive than Sinosaurosphargis. The only armor consists of small granular osteoderms. Compare to Claudiosaurus as this species makes a fine transitional morphology between the long Claudiosaurus to the short, turtle-like Sinosaurosphargis.

Omphalosaurus nevadanus (Merriam 1906, Motani 2000; Middle Triassic; worldwide distribtution) has been a traditional enigma, never before tested with Largocephalosaurus (above), with which it nests in the large reptile tree. Omphalosaurus had a crushing dentition at the anterior of its long rostrum. No specimens are articulated or near complete.

Cheng L, Chen X-H, Zeng X-W and Ca Y-J 2012. A new eosauropterygian (Diapsida: Sauropterygia) from the Middle Triassic of Luoping, Yunnan Province. Journal of Earth Science 23 (1): 33-40.

Li C, Rieppel O, Wu X-C, Zhao L-J and Wang LT 2011. A new Triassic marine reptile from southwestern China. Journal of Vertebrate Paleontology 31 (2): 303-312. doi:10.1080/02724634.2011.550368.

Li C, Jiang D-Y, Cheng L, Wu X-C and Rieppel O 2013. A new species of Largocephalosaurus (Diapsida:Saurosphargidae), with implications for the morphological diversity and phylogeny of the group.

Maisch M 2010. Phylogeny, systematics, and origin of the Ichthyosauria – the state of the art. Palaeodiversiry 3: 151-214.

Motani R 2000. Is Omphalosaurus ichthyopterygian? — A phylogenetic perspective. Journal of Vertebrate Paleontology 20(2): 295-301.

wiki/Largocephalosaurus
wiki/Omphalosaurus

Marine Younginiformes

Enaliosauria