PALEONEUROLOGÍA DE DOLICAVIA MINUSCULA (RODENTIA, CAVIIDAE) y PAEDOTHERIUM INSIGNE (NOTOUNGULATA, HEGETOTHERIIDAE) DEL PLIOCENO DE BUENOS AIRES, ARGENTINA

Abstract

"Based on a palaeoneurological study, the external neuromorphological characters of a Caviidae rodent (Dolicavia minuscula Ameghino) and a Hegetotheriidae notoungulate tPaedotherium insigne Burmeister) from the Chapadmalal Formation, are interpreted. The endocasts of these species show similar external brain morphologies incIuding the same pattem of neocortical sulci. Comparisons with brains of their possible ecological equivalents -rodents and lagomorphs- suggest that the brain of Paedotherium insigne is similar to those of Caviidae, particularly Caviinae (Cavia, Dolicaviai. AIso, this brain shares the same pattern that it is interpreted in other Hegetotheriidae (Hegetotherium, Pachyrukhos). It is proposed that the neuromorphological convergence between Hegetotheriidae and Caviidae has been closer than it is inferred from the osteological and dental characters. Indices of encephalization were computed. The relative brain size of P. insigne is lower than that of D. minuscula, being the last one at the level of the living Caviidae. "