The Triassic dicynodont Vinceria (Therapsida, Anomodontia) from Argentina and a discussion on basal Kannemeyeriiformes

DOMNANOVICH, NADIA; MARSICANO, CLAUDIA

GEOBIOS

ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER

Lugar: The Netherlands; Año: 2011

0016-6995

In 1969 Bonaparte described a new dicynodont, Vinceria andina, from the early Middle Triassic Cerro de las Cabras Formation of central- western Argentina (Potrerillos, Mendoza). Later, this author mentioned two additional specimens from the same beds, but they were never figured and/or described until now. Years later, another specimen identified as Vinceria sp. was briefly described from a different locality and stratigraphic level (Early– Middle Triassic Puesto Viejo Group, southern Mendoza). Vinceria has alternatively been considered to be related to the South African Kannemeyeria or to the shansiodontids from China, Tanzania, South Africa and Russia. Moreover, some authors considered Vinceria andina as a junior synonym of Kannemeyeria argentinensis. A recent phylogenetic analysis on Triassic dicynodonts, including Vinceria and the shansiodontids, resulted in a basal position of this group in relation to the other Triassic dicynodonts, the kannemeyeriiforms. Nevertheless, the interrelationships of Shansiodontidae are poorly understood. This situation is partially because of the lack of accurate descriptions of the poorly known specimens. The present paper is an exhaustive analysis of all materials once referred to Vinceria, plus some underscribed specimens, thus providing detailed anatomical descriptions and accurate figures of one of the putative basal members of the clade Kannemeyeriiformes. As a result, Vinceria is considered as a valid taxon that includes two species, V. andina and V. vieja nov. sp. Comparisons among the species of Vinceria and other shansiodontids question the characters used to justify the monophyly of the group.