Protypotherium globosum 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 globosum Ameghino, 1891

Holotype. MACN-A 4049 ( Figs. 2 M–N ), an almost complete skull lacking the left premaxilla.

Diagnosis ( Ameghino 1891: 292). “ Tamaño bastante más pequeño que el Protypotherium australe (Moreno) Ameghino. Se distingue por los parietales, que se levantan bastante más arriba que los frontales, de superficie globosa, cortos y que atrás descienden hacia abajo de una manera casi repentina. Frente muy ancha y plana; nasales cortos. Longitud del cráneo, 8 centímetros. Diámetro transverso máximo, 53 milímetros. Diámetro interorbitario de los frontales, 3 centímetros. Longitud de la serie dentaria superior, 45 milímetros ”.

English translation. Considerably smaller size than Protypotherium australe (Moreno) Ameghino. It can be distinguished by its short parietals that rise much higher than the frontals, with a globular surface, and suddenly descend downwards posteriorly. Forehead very broad and flat; nasals short. Length of the skull, 8 centimetres. Maximum transverse diameter, 53 millimetres. Interorbital diameter of the frontals, 3 centimetres. Length of upper tooth row, 45 millimetres.

Comments. Ameghino (1891) described this taxon without any illustration. According to Ameghino’s catalogue and to Mones (1986), the incomplete skull MACN-A 4049 is the type material of the species. This specimen matches the original diagnosis ( Ameghino 1891) both in morphology (e.g., the most posterior region of the frontals and the anterior portion of the parietals form a convex surface that rapidly descends posteriorly, frontals are wide and flat, and nasals and parietals are short) and measurements (length of the skull = 84.2 mm; maximum transverse diameter = 53.4 mm; interorbital frontal diameter = 30.1 mm; length of the upper tooth row = 45 mm), and it is herein confirmed as the holotype of P. globosum .

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.