Protypotherium convexidens 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

Protypotherium convexidens Ameghino, 1891

Holotype. MACN-A 4054 ( Fig. 2 O ), right maxilla with P3–M2 (broken).

Diagnosis ( Ameghino 1891: 292). “ De tamaño un poco menor que Protypotherium australe (Moreno) Ameghino , del cual se distingue fácilmente por sus molares superiores de cara externa ligeramente ondulada y convexa en su conjunto. Longitud del espacio ocupado por los p.3 a m.2, 19 milímetros ”.

English translation. Slightly smaller than Protypotherium australe (Moreno) Ameghino , from which it is easily distinguished by the external face of upper molars softly undulated and convex as a whole. Length occupied by P3 to M2, 19 millimetres.

Comments. Ameghino (1891) described this taxon without any illustration. According to Ameghino’s catalogue and to Mones (1986), the maxillary fragment MACN-A 4050 is the type of the species. However, MACN-A 4050 does not match the specimen originally described, because it is a maxillary fragment with P4–M1, with no evidence of recent breaks; in consequence, the specimen MACN-A 4050 cannot be considered as the holotype of the species. Instead, the specimen MACN-A 4054, a maxilla with P3–M1 and broken M2, matches the measurement (length of P3–M2 = 18.9 mm) and the original description provided by Ameghino (1891), because it is smaller than the holotype of P. australe (length of P3–M2 = 32 mm) and presents upper molars slightly labially undulated. Therefore, MACN-A 4054 is herein considered as the holotype of P. convexidens .

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.