Protypotherium diversidens Ameghino, 1891

Fernández, Mercedes, Fernicola, Juan Carlos, Cerdeño, Esperanza & Reguero, Marcelo A., 2018, Identification of type materials of the species of Protypotherium Ameghino, 1885 and Patriarchus Ameghino, 1889 (Notoungulata: Interatheriidae) erected by Florentino Ameghino, Zootaxa 4387 (3), pp. 473-498 : 485-486

Protypotherium diversidens Ameghino, 1891

Holotype. MACN-A 4052 ( Fig. 2 P ), right maxilla with alveolus of P1 and P2–M3.

Diagnosis ( Ameghino 1891: 292). “ De tamaño relativamente pequeño. Se distingue fácilmente por los premolares superiores que presentan el surco perpendicular externo, profundo, ancho en la corona, que se angosta y desaparece pronto hacia la base en vez de seguir de un extremo al otro del diente como en las demás especies. Longitud del espacio ocupado por los p.2 a m.2, 24 milímetros ”.

English translation. Species of relatively small size. It is easily distinguished by the upper premolars with a deep and wide external groove that rapidly narrows and disappears towards the base, instead of being continuous from the top to the basal end of the tooth as in the other species. Length occupied by P2 to M2, 24 millimetres.

Comments. Ameghino (1891) described this taxon but did not figure it. According to Ameghino’s catalogue and to Mones (1986), right maxilla MACN-A 4052 is the type specimen of the species. The premolars of MACN- A 4052 exhibit the discontinuous external sulcus indicated in the original description, and the length of the series P2–M2 (24.34 mm) also matches the value provided originally. As a result, this specimen is confirmed as the holotype of P. diversidens .

Chronological and geographical distribution of the type specimen. Santacrucian SALMA, Santa Cruz Province.

Figures

FIGURE 2. Protypotherium attenuatum, syntype MACN-A 524, left maxilla with P2–M3 but lacking P1, in occlusal view (A); syntype MACN-A 628, right fragmented mandible with alveoli of i1–3 and c (broken)–m1 but lacking m2–3, in labial (B) and occlusal (C) views; reproductions of figures 21 (D), 20 (E) and 20a (F) from Ameghino (1889, plate 14). Protypotherium obstructum, holotype MACN-A 1677, lower premolar in labial, oclusal and lingual views (G); reproduction of figure 19 (H) from Ameghino (1889, plate 15). Protypotherium claudum, holotype MACN-A 551, right mandibular fragment with alveolus of p2 andp3–m2, in labial (I) and occlusal (J)views; reproductions of figures 22 (K) and 22a (L) from Ameghino (1889, plate 14). Protypotherium globosum, holotype MACN-A 4049, skull, in ventral (M) and dorsal (N) views. Protypotherium convexidens, holotype MACN-A 4054, right maxillary fragment with P3–M2 (broken), in occlusal view (O). Protypotherium diversidens, holotype MACN-A 4052, right maxillary fragment with alveolus of P1 and P2–M3, in occlusal view (P). Protypotheriumcompressidens, holotype MACN-A 4029, left maxillaryfragment withP3–M3, in occlusal view (Q); holotype MACN-A 4030, left mandibular fragment with p4 (talonid)–m3, in occlusal view (R). Protypotherium lineare, holotype MACN-A4039, right mandibular fragment with alveolus of p1 and p2–m1, in occlusal view (S); holotype MACN-A 4038, left mandibular fragment with p3–m2, in occlusal view (T). Scale bar = 10 mm.