Prostichomys bowni, un nuevo roedor Adelphomyinae (Hystricognathi, Echimyidae) del Mioceno medio - inferior de Patagonia, Argentina.

KRAMARZ, A.

AMEGHINIANA

Asociación Paleontológica Argentina

Lugar: Buenos Aires; Año: 2001 vol. 38 p. 163 - 168

0002-7014

A  new  genus  and  species,  Prostichomys bowni, from  the early Santacrucian Age, Pinturas Formation,  is described. This is the first record of Echimyidae for this formation. The molariphorms are very similar in morphology to Stichomys (from the Santacrucian Age), but more primitive by having upper molars  more quadrangular in outline, less inclined crests, and labial flexii wider and more penetrating; the lowers have complete mesolophid in m1, absent in m3  and variably reduced in dp4 and m2; the lower incisors are posteriorly longer.  Protacaremys (from the Coluehuapian and Colloncuran age) shows a dentition structurally ancestral to Prostichomys and here is included in the Adelphomyinae. Protacaremys, Prostichomys, Stichomys and Adelphomys represent a single phyletic line different to the Prospaniomys - Spaniomys - Maruchito group (here exlcuded from the Adelphomyinae), Xilechimys - Paradelphomys group and Deseadomys. The intermediate evolutionary stage between the colhuehuapian and santacrucian genera of the dentition of Prostichomys is coherent with antiquity inferred for the Pinturas Formation.