''Coahomasuchus'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

aetosaurine Aetosaurinae is one of the two main clades of aetosaurs, the other being Desmatosuchia. It is a stem-based taxon defined as all aetosaurs more closely related to ''Aetosaurus'' than ''Desmatosuchus''. Aetosaurinae currently comprises ''Aetosauru ...

aetosaur Aetosaurs () are heavily armored reptiles belonging to the extinct order Aetosauria (; from Greek, (aetos, "eagle") and (, "lizard")). They were medium- to large-sized omnivorous or herbivorous pseudosuchians, part of the branch of archosaurs ...

. Remains of the genus have been found from deposits in

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

and

North Carolina North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia a ...

that date to the Otischalkian

faunachron In paleontology, biochronology is the correlation in time of biological events using fossils. In its strict sense, it refers to the use of assemblages of fossils that are not tied to stratigraphic sections (in contrast to biostratigraphy, where th ...

(lower late

Carnian The Carnian (less commonly, Karnian) is the lowermost stage of the Upper Triassic Series (or earliest age of the Late Triassic Epoch). It lasted from 237 to 227 million years ago (Ma). The Carnian is preceded by the Ladinian and is followe ...

) of the

Late Triassic The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch ...

. It was small for an aetosaur, being less than long. The dorsal plates are distinctively flat and unflexed, and have a faint sub-parallel to radial ornamentation. The genus lacked spines or keels on these plates, features seen in many other aetosaurs. ''Coahomasuchus'' was very similar in appearance to the closely related ''

Aetosaurus ''Aetosaurus'' is an extinct genus of pseudosuchian reptile belonging to the order Aetosauria. It is generally considered to be the most primitive aetosaur. Three species are currently recognized: ''A. ferratus'', the type species from Germany a ...

''. Two species of ''Coahomasuchus'' are known. ''C. kahleorum'', the type species, was named by Heckert and Lucas in 1999; it is known from the Colorado City Formation of the

Dockum Group The Dockum is a Late Triassic (approximately late Carnian through Rhaetian, or 223–200 Ma) geologic group found primarily on the Llano Estacado of western Texas and eastern New Mexico with minor exposures in southwestern Kansas, eastern Color ...

. ''C. chathamensis'', a second species named by Heckert ''et al.'' in 2017, is from the

Pekin Formation The Pekin Formation is a Late Triassic (Carnian) geological formation in North Carolina. The Pekin Formation is specific to the Sanford Sub-Basin of the Deep River Basin of North Carolina, although it may be equivalent to the Stockton Formation of ...

of the

Newark Supergroup The Newark Supergroup, also known as the Newark Group, is an assemblage of Upper Triassic and Lower Jurassic sedimentary rocks which outcrop intermittently along the United States East Coast. They were deposited in a series of Triassic basins ...

. The holotype of the latter species contains parts of the skull, which is rare among aetosaurs. ''C. chathamensis'' differs from ''C. kahleorum'' by wider osteoderms on the back and the underside of the neck, as well as the relative lengths of the processes of the

surangular The suprangular or surangular is a jaw bone found in most land vertebrates, except mammals. Usually in the back of the jaw, on the upper edge, it is connected to all other jaw bones: dentary, angular, splenial and articular The articular bone ...

References

External links

''Coahomasuchus''
at

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Aetosaurs of North America Prehistoric pseudosuchian genera {{triassic-reptile-stub