''Chasmatosuchus'' was an archosauriform reptile from the early

Triassic The Triassic ( ) is a geologic period and system (stratigraphy), system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Year#Abbreviations yr and ya, Mya), to the beginning of the Jurassic Period 201.36 ...

period of European Russia. One of the earliest described archosauriforms, it was over 2 m long and is thought to have behaved like a modern crocodile. Its mouth had two distinct features: the top of its jaw hooked downwards to aid in holding prey, and the upper palate was lined with a row of teeth—a primitive feature lost in later

archosaurs Archosauria () is a clade of diapsids, with birds and crocodilians as the only living representatives. Archosaurs are broadly classified as reptiles, in the cladistic sense of the term which includes birds. Extinct archosaurs include non-avia ...

. ''Chasmatosuchus'' was formerly assigned to

Proterosuchidae Proterosuchidae is an early family of basal archosauriforms whose fossils are known from the Latest Permian and the Early Triassic of Europe, Asia, Africa, Australia and possibly South America. The name comes from Greek πρότερο- ("first" ...

, but a 2016 cladistic analysis by Martin Ezcurra couldn't confidently place the species of ''Chasmatosuchus'' within Proterosuchidae. Instead their position remains unresolved due to the fragmentary nature of the known material, however ''Chasmatosuchus'' is more likely to be intermediate between proterosuchids and erythrosuchids and possibly closely related to '' Sarmatosuchus otschevi'' and '' Cuyosuchus huenei''. Ezcurra (2016) could only placed ''C. rossicus'' and ''C. magnus'' within ''Chasmatosuchus'' with certainty, while the third valid species''"C." vjushkovi'' potentially does not belong to ''Chasmatosuchus'' and may represent a proterosuchid. ''Gamosaurus'' and ''Jaikosuchus'' are subjective junior synonyms of ''Chasmatosuchus''.Ezcurra, M.D. (2016),The phylogenetic relationships of basal archosauromorphs, with an emphasis on the systematics of proterosuchian archosauriforms. PeerJ4:e1778;DOI10.7717/peerj.1778 ''Chasmatosuchus parvus'', based on an anterior cervical vertebra, was synonymized with '' Macrocnemus'' in 1995.Sennikov AG, 1995. Early thecodonts of Eastern Europe. Trudy Paleontologischeskogo Instituta RAN 263:1–141(in Russian).

References

Prehistoric archosauriforms Early Triassic reptiles of Europe Fossil taxa described in 1940 Prehistoric reptile genera {{triassic-reptile-stub