Protypotherium australe ( Ameghino, 1887a )

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 : 480-481

Protypotherium australe ( Ameghino, 1887a)

Holotype. Left maxilla with P3–M3; original piece has not been found, but there are two casts in the MACN: MACN-A 1338 ( Fig. 1 G ) and MACN-A 1345–46.

Diagnosis ( Ameghino 1887a: 63). “ Talla comparable a la del Dolichotis patachonica . Corona de los molares superiores fuertemente excavada. Paladar poco profundo y relativamente plano. Lóbulo anterior de los verdaderos molares superiores un poco más ancho que el posterior. […] De este animal sólo se conoce el maxilar superior izquierdo, con las cinco últimas muelas más o menos rotas, excepto las dos últimas, que están enteras. Ha sido encontrado, como el precedente, por F. P. Moreno, durante su viaje de 1876–1877 ”.

English translation. Size similar to that of Dolichotis patachonica . Crown of upper cheek teeth strongly excavated. Palate shallow and relatively flat. Anterior lobe of upper molars slightly wider than the posterior one. [...] This animal is only known from the left upper jaw, with the last five cheek teeth more or less broken, except for the last two that are complete. It has been found, like the precedent, by F. P. Moreno, during his 1876 – 1877 exploration.

Comments. In the original diagnosis, Ameghino (1887a) highlighted that the maxilla collected by Moreno was the only known material of P. australe . Shortly after, Ameghino (1887b) completed the former diagnosis by giving the dimensions of a mandibular fragment with at least p1–m3. Once again, Ameghino (1889, plate 14: figs. 9–11, 14–18) expanded the original description of the species and illustrated three isolated upper teeth (I1, P2 and M1; figs. 9–11), three isolated lower teeth (p3, p4 and m1; figs. 14–16), a right maxillary fragment with P4–M3 (fig. 17), and a left mandibular ramus with its teeth (fig. 18). It is worth to mention that he recognised that by 1889 this species was known only by fragmentary materials and that there was no complete upper or lower series available. None of these illustrated specimens is the left maxilla used in the original description as they involve isolated teeth, a mandibular fragment and a right maxilla, which leads us to conclude that the holotype was not illustrated. According to Ameghino’s catalogue, MACN-A 3882, an incomplete skull with almost complete dentition (alveoli of both I1 and left I2–3, and complete right I2 –M3 and left C–M3), and MACN-A 3884, a mandibular symphysis and its right mandibular ramus, are the type specimens. In contrast, Mones (1986) did not indicate any type specimen, and just mentioned “MLP (-)”, meaning that it was supposed to be housed at the MLP but that it could also be lost.

MACN-A 3882 is discarded as the holotype because it does not correspond to the fragmented left maxilla initially described by Ameghino (1887a). In turn, MACN-A 3884 is the mandibular fragment described shortly after ( Ameghino 1887b), but it is not part of the type material as this is only composed of one specimen as highlighted by Ameghino (1887a), which is the maxillary fragment that constitutes the holotype. In contrast, there are two identical casts in the Ameghino Collection, MACN-A 1338 and MACN-A 1345–46, which match the original diagnosis as they are the casts of a left maxilla with broken P3, labially incomplete P4–M1 and complete M2–3, strongly excavated tooth row, and M1–3 with anterior lobe slightly wider than the posterior lobe. In addition, Ameghino wrote “Moreno” next to the description of MACN-A 1338 in his catalogue, and “tipo de Toxodontophanus Mo. ” next to MACN-A 1345–46, a fact that reinforces the inference that they correspond to the maxilla collected by Moreno and, therefore, both are recognised as casts of the holotype.

Unfortunately, the original piece has not been located, as no specimen in the studied collections—by direct observations (e.g., MACN, MLP and ZMK) and/or by means of photographs (e.g., AMNH, FM and YPM)— matches the original description of P. australe and the casts MACN-A 1338 and MACN-A 1345–46.

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

Figures

FIGURE 1. Protypotherium antiquum, lectotype ZMK 21/1877, right mandibular fragment with p4-m3, in labial (A) and occlusal (B) views; reproductions of figures 1 (C) and 1a (D) from Ameghino (1889, plate 15); and MACN-A 1288, cast of lectotype, inlabial (E) and occlusal(F)views. Protypotherium australe, MACN-A 1338, cast of theholotype, in occlusalview (G). Protypotherium praerutilum, holotype MACN-A 1081, incomplete skull, in ventral (H) and dorsal (I) views; holotype MACN-A 1082, incomplete mandible, in lateral (J) and occlusal (K) views; reproductions of figures 6 (L) and 6a (M) from Ameghino (1889, plate 14); reproductions of figures 7 (N) and 7a (O) from Ameghino (1889, plate 14). Scale bar = 10 mm.