''Plinthogomphodon'' 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 of traversodontid

cynodont The cynodonts () (clade Cynodontia) are a clade of eutheriodont therapsids that first appeared in the Late Permian (approximately 260 mya), and extensively diversified after the Permian–Triassic extinction event. Cynodonts had a wide variety ...

s from the Late Triassic of the eastern United States. Fossils have been found from the

Deep River basin Deep or The Deep may refer to: Places United States * Deep Creek (Appomattox River tributary), Virginia * Deep Creek (Great Salt Lake), Idaho and Utah * Deep Creek (Mahantango Creek tributary), Pennsylvania * Deep Creek (Mojave River tributary), ...

of North Carolina, part of the larger Newark Supergroup. It is known from a single eroded snout. The

type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * Ty ...

and only species is ''P. herpetairus''.

Description and history

''Plinthogomphodon'' was named in 1999. The name means "brick molar tooth" in Greek, as it was found in

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from '' shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology. ...

used to make bricks and its postcanine teeth resemble molars. The type species is ''P. herpetairus'', meaning "companion of reptiles" from the Greek ''herpeton'' ("reptile") and ''hetairos'' ("companion"). The name alludes to the close proximity of the holotype specimen to the remains of a rauisuchian ('' Postosuchus alisonae'') and a sphenosuchian

archosaur 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-avian d ...

(''

Dromicosuchus ''Dromicosuchus'' ( Ancient Greek, meaning "fleet or quickly walking crocodile") is an extinct genus of sphenosuchian, a type of basal crocodylomorph, the clade that comprises the crocodilians and their closest kin. It was found in Upper Tria ...

'') when it was first discovered. It is thought that the ''Plinthogomphodon'' had been previously consumed by the ''Postosuchus'', which died and was buried when pursuing the ''Dromicosuchus''. The holotype only preserves the underside of the snout, as the dorsal surface has eroded away. The tip of the snout is broad, but it constricts behind the canines. The tips of most teeth are also worn away, except for two postcanine teeth that had not yet erupted and were exposed during the fossil's preparation for study. Because the teeth had not yet emerged, the individual was probably a juvenile. Like most traversodotids, ''Plinthogomphodon'' has a pair of large canine teeth and several wide, cusped postcanine teeth. The postcanines of ''Plinthogomphodon'' are much wider than they are long and closely packed together. Based on the postcanine that had not erupted in the holotype, the postcanine of ''Plinthogomphodon'' has three main cusps: a lingual cusp near the mouth, a slightly smaller central cusp, and a relatively large buccal cusp near the cheek. There are also smaller accessory cusps in front of the buccal cusp.

References

{{Taxonbar, from=Q3558294 Traversodontids Late Triassic synapsids of North America Fossil taxa described in 1999