Interatherium anguliferum Ameghino, 1894a

Fernández, Mercedes, Fernicola, Juan Carlos & Cerdeño, Esperanza, 2019, On the type materials of the genera Interatherium Ameghino, 1887 and Icochilus Ameghino, 1889 (Interatheriidae, Notoungulata, Mammalia) from early Miocene of the Santa Cruz Province, Argentina, Zootaxa 4543 (2), pp. 195-220 : 201

Interatherium anguliferum Ameghino, 1894a

Holotype. MACN-A 3444 ( Fig. 1 C ), a fragmented right maxilla with C and P2–M1 series.

Age and provenance of the type material. Santacrucian SALMA, early Miocene , Santa Cruz Province ( Argentina).

Original description ( Ameghino 1894a: 18). “ De taille intermédiaire entre celle de 1’ I. rodens et celle de 1’ I. supernum dont elle se distingue par l'absence de la première prémolaire supérieure. La canine supérieure est bien développée et isolée par des diastèmesen avant et en arrière. Les p. 2 à 4 ont les deux arêtes perpendiculaires de l'angle antérieur externe très fortes. Longueur du bord antérieur de la canine au bord postérieur de la première vraie molaire supérieure, 17 mm ”.

English translation. Size intermediate between I. rodens and I. supernum , from which it is distinguished by the absence of the first upper premolar. The upper canine is well developed and anteriorly and posteriorly isolated by diastemata. P2–4 have the two perpendicular columns of the antero-external angle very strong. Length from the anterior region of the upper canine to the posterior border of the first true upper molar, 17 mm.

Comments. Ameghino (1894a) did not illustrate any specimen of this species. According to Ameghino’s catalogue and Mones (1986), the maxilla MACN-A 3444 is the type specimen of the species. This material matches the original description provided by Ameghino (1894a) because its dP1 is absent, there are diastemata anterior and posterior to C, and the series C–M1 is 17.3 mm long. Therefore, MACN-A 3444 is confirmed as the holotype of I. anguliferum .

Figures

FIGURE 1. Interatherium rodens, holotype MLP 12-2826, right maxilla with alveolus of dP1 and complete dP2 and P3–M3, in occlusal view (A); reproduction of figure 26 (B) from Ameghino (1889, plate 15). Interatherium anguliferum, holotype MACN-A 3444, right maxilla with C and P2–M1, in occlusal view (C). Interatherium interruptum, holotype MACN-A 3445, left maxilla with the alveolus of dP1 and complete dP2–3 and P4–M3, in occlusal view (D). Interatherium dentatum, holotype MACN-A 9863, skull and mandible articulated, left lateral view (E). Scale bar = 10 mm.