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Vinceria, dicynodont from Middle Triassic of Argentina, validated



From:  Ben Creisler
bcreisler@gmail.com

OK, it's not a dinosaur...This new paper adds to the spate of recent
articles about Triassic vertebrates that would have competed with the
archosaur ancestors of dinosaurs.

Nadia S. Domnanovich & Claudia A. Marsicano (2012)
The Triassic dicynodont Vinceria (Therapsida, Anomodontia) from
Argentina and a discussion on basal Kannemeyeriiformes.
Geobios (advance online publication)
http://dx.doi.org/10.1016/j.geobios.2011.03.003
http://www.sciencedirect.com/science/article/pii/S0016699512000150?v=s5


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 remain poorly understood. This
situation is partially due to 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 undescribed
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