Icochilus curtus 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 : 215

Icochilus curtus 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: 17). “ De la même taille que l’ I. extensus . Cette espèce se distingue facilement par le grand raccourcissement de la dernière molaire inférieure qui est à peine un peu plus longue que l'avant-dernière, et par son lobe postérieur qui est convexe sur le côté externe, sans vestige du sillon perpendiculaire qu'on voit sur la même dent des autres espèces. La dernière molaire inférieure a près de 5 mm. de longueur, et les deux dernières molaires occupent un espace de 9 mm. de long ”.

English translation. With the same size as Ic. extensus . This species is easily distinguished by the great shortening of the last lower molar, which is just a little longer than m2, and by its posterior lobe that is convex on the external side and it does not exhibit the perpendicular groove seen on the same tooth in the other species. The last lower molar is nearly 5 mm long, and the last two molars occupy a space of 9 mm.

Comments. Ameghino (1894a) did not illustrate this species. According to Ameghino’s catalogue and Mones (1986), the mandibular fragment MACN-A 9852 is the type material of the species. However, MACN-A 9852 does not match the original description, because its m3 exhibits a labial groove in the talonid as in other species of Icochilus . Among the remaining specimens assigned to this species within the Ameghino Collection, other two fragmented mandibles, MACN-A 9853 and MACN-A 9854, neither present the diagnostic characteristics described for the m3. In addition, no material labelled as Icochilus sp., Interatherium sp., Icochilini, Icochilinae and Interatheriidae indet. matches the original description provided by Ameghino (1894a). As a result, the type specimen of Ic. curtus has not been located.