Discoveries in the Late Triassic of Brazil improve knowledge on the origin of mammals

JOSE BONAPARTE; MARINA BENTO SOARES; AGUSTIN MARTINELLI

Historia Natural, Tercera Serie

Fundación Felix de Azara

Lugar: Buenos Aires; Año: 2012 vol. 2012 p. 5 - 30

A new specimen of Brasilitherium riograndensis, which includes complete skull, lowerjaws, dentition and some postcranial bones, is described, along with a redescription of the skull, lower jaws and dentition of Minicynodon maieri, both derived eucynodonts from the Late Triassic of Southern Brazil. The anatomical comparison confirms the close relationships of both genera with the Morganucodonta and suggest that the Tritheledontidae is the sister group of the Brasilodontidae. Some comments after the anatomical information from the brasilodontids are developed on the following subjects: the sister group of mammals, the interpterygoid vacuity, and on Adelobasileus, Hadrocodium and Microconodon.