Pascualgnathus is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of traversodontid cynodont

Cynodont

Cynodontia or cynodonts are a taxon of therapsids which first appeared in the Late Permian and were eventually distributed throughout all seven continents by the Early Triassic . This clade includes modern mammals and their extinct close relatives. They were one of the most diverse groups of...

 from the Middle Triassic

Middle Triassic

In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided. It spans the time between 245 ± 1.5 Ma and 228 ± 2 Ma...

 of Argentina

Argentina

Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

. Fossils have been found from the Río Seco de la Quebrada Formation. 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

Trirachodon is an extinct genus of tritylodontoid cynodont. Fossils have been found from the Cynognathus Assemblage Zone of the Beaufort Group in South Africa, dating back to the Early and Middle Triassic.-Description:...

than the South American genus Diademodon

Diademodon

Diademodon is an vegetarian extinct genus of therapsid. It was about the size of a small cow. Fossils of the Diademodon tetragonus were found in levels of the Rio Seco de la Quebrada geological formation in Mendoza Province, Argentina....

. 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.