''Pascualgnathus'' is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of traversodontid

cynodont Cynodontia () is a clade of eutheriodont therapsids that first appeared in the Late Permian (approximately 260 Megaannum, mya), and extensively diversified after the Permian–Triassic extinction event. Mammals are cynodonts, as are their extin ...

s from the

Middle Triassic In the geologic timescale, the Middle Triassic is the second of three epoch (geology), epochs of the Triassic period (geology), period or the middle of three series (stratigraphy), series in which the Triassic system (stratigraphy), system is di ...

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

. Fossils have been found from the Río Seco de la Quebrada Formation of the Puesto Viejo Group. The type species ''P. polanskii'' was named in 1966.

Description

''Pascualgnathus'' is a small traversodontid. It has large upper canine teeth and small postcanine teeth. The postcanine teeth of ''Pascualgnathus'' and other traversodontids are wide, allowing them to eat plant material. The upper postcanines of ''Pascualgnathus'' are rectangular. Each has a central ridge and a cusp on the side facing the mouth. There are also two cusps on the side of the tooth facing the lips, with one being larger than the other. The lower postcanines have less of a rectangular shape and have only two cusps. Unlike the upper postcanines, they are longer than they are wide.

Classification

When ''Pascualgnathus'' was first named in 1966, it was considered a member of the family Diademodontidae more closely related to the African genus ''

Trirachodon ''Trirachodon'' (Greek: "three ridge tooth") is an extinct genus of cynodonts. Fossils have been found in the ''Cynognathus'' Assemblage Zone of the Beaufort Group in South Africa and the Omingonde Formation of Namibia, dating back to the Earl ...

'' than the South American genus ''

Diademodon ''Diademodon'' is an extinct genus of cynodonts. It was about long. Discovery Harry Seeley had found his fossil in the Burgersdorp Formation of the Beaufort Group in the Karoo Basin of South Africa. As late as 1988, ''Diademodon'' had ...

''. ''Diademodon'' was later uncovered from the Río Seco de la Quebrada Formation alongside ''Pascualgnathus'', suggesting that the ancestors of ''Pascualgnathus'' migrated from Africa to South America.

References

{{Taxonbar, from=Q7141870 Traversodontidae Middle Triassic synapsids of South America Fossil taxa described in 1966 Taxa named by José Bonaparte Triassic Argentina