Icochilus robustus Ameghino, 1891

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 : 209

Icochilus robustus Ameghino, 1891

Holotype. MACN-A 3454 ( Fig. 4A ) to MACN-A 3505 , complete skull and mandible of the same individual, with associated postcranial elements.

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

Original description ( Ameghino 1891: 393). “ Del tamaño de Icochilus extensus , del que se distingue por el cráneo más ancho y por los frontales que se prolongan adelante entre los nasales ”.

English translation. Of the same size as Icochilus extensus , from which it is distinguished by presenting a wider skull and the frontals extended forward between the nasals.

Comments. Ameghino (1891: 393, figs. 95–97) briefly described this species in a footnote, stating that he had the entire skeleton of an individual. He also illustrated a foot, a right hand and an almost complete skull.

According to Ameghino’s catalogue and Mones (1986), MACN-A 3454 to MACN-A 3505, an almost complete individual, constitute the type specimen of the species. MACN-A 3454 is indeed the illustrated complete skull ( Ameghino 1891: fig. 97), herein reproduced ( Fig. 4 B ), although it has suffered many breaks. Regarding the right manus and foot, only some elements (basipodia, metapodia and phalanges) are present. At the beginning of the current study, all of these materials were in different uncovered containers, so it is assumed that different elements have been missed over the years. Therefore, MACN 3454 to MACN-A 3505 are confirmed as elements of the holotype of Ic. robustus .

Figures

FIGURE 4. Icochilus robustus, holotype MACN-A 3454, skull, in dorsal view (A); reproduction of figure 97 (B) from Ameghino (1891). Icochilus senilis, holotype MACN-A 3596, incomplete skull, in ventral view (C); holotype MACN-A 3597, incomplete mandible, in dorsal view (D). Scale bar = 10 mm.