''Coelodontognathus'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of reptile from the

Early Triassic The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic Series, which is a un ...

(late

Olenekian In the geologic timescale, the Olenekian is an age in the Early Triassic epoch; in chronostratigraphy, it is a stage in the Lower Triassic series. It spans the time between Ma and Ma (million years ago). The Olenekian is sometimes divided into ...

stage) of

European Russia European Russia (russian: Европейская Россия, russian: европейская часть России, label=none) is the western and most populated part of Russia. It is geographically situated in Europe, as opposed to the cou ...

. It was originally described as a

procolophonid Procolophonidae is an extinct family of small, lizard-like parareptiles known from the Late Permian to Late Triassic that were distributed across Pangaea, having been reported from Europe, North America, China, South Africa, South America, Antarc ...

parareptile Parareptilia ("at the side of reptiles") is a subclass or clade of basal sauropsids (reptiles), typically considered the sister taxon to Eureptilia (the group that likely contains all living reptiles and birds). Parareptiles first arose near the ...

in 1967 but was reclassified as a possible

trilophosaurid Trilophosaurs are lizard-like Triassic allokotosaur reptiles related to the archosaurs. The best known genus is ''Trilophosaurus'', a herbivore up to long. It had a short, unusually heavily built skull, equipped with massive, broad flattened che ...

archosauromorph Archosauromorpha (Greek for "ruling lizard forms") is a clade of diapsid reptiles containing all reptiles more closely related to archosaurs (such as crocodilians and dinosaurs, including birds) rather than lepidosaurs (such as tuataras, liza ...

in 2008. The genus includes two species: the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

''C. donensis'' and ''C. ricovi''. ''C. donensis'' is known from the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

PIN 4173/129 (SGU 104/3103) and the referred PIN 4173/130 (SGU 104/3104), and ''C. ricovi'' is known from the holotype PIN 4173/127 (SGU 104/3101) and the referred PIN 4173/128 (SGU 104/3102), all of which represent dentaries that are housed at the

Paleontological Institute, Russian Academy of Sciences The Paleontological Institute, Russian Academy of Sciences (PIN; russian: Палеонтологический институт РАН) in Moscow is among the world's largest paleontological institutes. An affiliate of the Russian Academy of Scienc ...

. Another dentary, SGU 104/3105, originally referred to ''C. donensis'' was reassigned to its own genus and species '' Vitalia grata'' by Ivakhnenko, 1973. The fossils have been found at the Donskaya Luka Locality near the village of Sirotinskaya and the

Don River The Don ( rus, Дон, p=don) is the fifth-longest river in Europe. Flowing from Central Russia to the Sea of Azov in Southern Russia, it is one of Russia's largest rivers and played an important role for traders from the Byzantine Empire. Its ...

Ilovlinsky District Ilovlinsky District (russian: Иловли́нский райо́н) is an administrativeLaw #139-OD district (raion), one of the thirty-three in Volgograd Oblast, Russia. As a municipal division, it is incorporated as Ilovlinsky Municipal Distri ...

Volgograd Oblast Volgograd Oblast (russian: Волгогра́дская о́бласть, ''Volgogradskaya oblast'') is a federal subjects of Russia, federal subject (an oblast) of Russia, located in the Volga region, Volga region of Southern Russia. Its adminis ...

, from the

Lipovskaya Formation The Yarenskian Gorizont (geology), Gorizont ("Yarenskian Horizon") is a major biostratigraphic unit in Russia corresponding to Upper Olenekian-age terrestrial sediments. It lies above the Ustmylian Gorizont of the Vetlugian Supergorizont, and is lo ...

of the Gamskii Horizon. Like ''Coelodontognathus'', '' Vitalia'' which is known from the same locality was also first identified as a procolophonid and later reclassified as a trilophosaurid. ''Coelodontognathus'' and ''Vitalia'' are similar to procolophonids in that they have wide teeth but differs from them in that they have tooth roots set deep into the jaws.

References

Allokotosaurs Prehistoric reptile genera Olenekian genera Early Triassic reptiles of Europe Triassic Russia Fossils of Russia Fossil taxa described in 1967 {{triassic-reptile-stub