Protypotherium Ameghino, 1885

Vera, Bárbara, Reguero, Marcelo & González-Ruiz, Laureano, 2017, The Interatheriinae notoungulates from the middle Miocene Collón Curá Formation in Argentina, Acta Palaeontologica Polonica 62 (4), pp. 845-863 : 848

Genus Protypotherium Ameghino, 1885

Type species: Protypotherium antiquum Ameghino, 1885 ; Huayqueri- an SALMA, Entre Ríos Province .

Emended diagnosis (from Ameghino 1885 and Sinclair 1909).— Protypotherium differs from Interatherium and Cochilius in having P/p3–P/p4 completely differentiated from molars, presence of mesial sulcus on P2–4, P4 nearly square or wider than long, upper molars usually coequal in size but may slightly diminish in size posteriorly, i3 ≥ i2, lower canine similarly sized to i3, smaller talonid than trigonid on p3–4, sulcus shallow in the talonid of m3, and little or moderately developed descending process of the maxilla. Protypotherium is characterized by having P-shaped trigonid and triangular talonid on m1–2 (in contrast to Interatherium , Cochilius , and Miocochilius ), and an entepicondylar foramen in the humerus (absent in Interatherium ). Unlike Miocochilius , Protypotherium has a caniniform p1 and a shorter m3.