Interatherium brevifrons 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 brevifrons Ameghino, 1894a

Holotype. Not located, probably lost.

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

Original description ( Ameghino 1894a: 18). “ Espèce de taille beaucoup plus petite que le I. rodens et avec toute la denture en série continue, sans diastèmes. La partie antérieure du crâne est très raccourcie. L'i. 1 est très grande et les i. 2 et 3 très petites. La canine est bien développée. Longueur de la partie antérieure de l'i. 1 à la partie postérieure de la m 3, 27 mm ”.

English translation. Species much smaller in size than I. rodens and with all the dentition in continuous series, without diastemata. The anterior part of the skull is very short. I1 is very large and I2–3 are very small. The canine is well developed. Length from the anterior part of I1 to the posterior part of m3, 27 mm.

Comments. Ameghino (1894a) did not add any illustration to the original description of the species. According to Ameghino’s catalogue, the cranial fragment MACN-A 3440 is the type specimen of I. brevifrons . Instead, Mones (1986) indicates the fragmented maxilla MACN-A 3441 as such.

MACN-A 3440 does not match the original description because it does not exhibit a complete dental series and it presents two diastemata, anterior and posterior to the upper canine. Therefore, it is discarded as the type specimen of the species. On the other hand , MACN-A 3441 can neither be considered the type material, because it is a very fragmented specimen with only three molariforms (Ameghino’s catalogue indicates “ tres muelas ” [three cheek teeth], so there is no option of having lost any dental piece through time) .

Unfortunately, no material that matches the original description ( Ameghino 1894a) was located within the studied collections.