The sister-group of mammals: Brasilodon and Brasilitherium (Cynodontia, Probainognathia) from the late Triassic of southern Brazil

JOSE BONAPARTE; AGUSTIN MARTINELLI; CESAR SCHULTZ

REVISTA BRASILEIRA DE PALEONTOLOGIA

SOC BRASILEIRA PALEONTOLOGIA

Lugar: Porto Alegre; Año: 2005 vol. 8 p. 25 - 46

1519-7530

New discoveries of articulated skulls and lower jaws of Brasilodon and Brasilitherium from the Late Triassic of Brazil present new information on these small cynodonts and permit us to establish the family Brasilodontidae nov. The basicranium, lateral wall of the braincase, primary and secondary palates and the quadrate of Brasilitherium are described, as well as the basicranium, primary palate and lower jaw of Brasilodon. Brasilitherium exhibits more derived characters than Brasilodon in the periotic, the promontorium, and the articular process of the dentary, whereas Brasilodon is more derived in the lower dentition, the mode of tooth replacement, and the vascular features in the ?stapedial recess?. Both genera have interpterygoid vacuities that are considered here as possibly derived characters of the mammalian primary palate. The new phylogenetic analysis of both genera presented here confirms their position as sister-group of mammals proposed in a previous study.