Revision taxonomica de Parahyaenodon argentinus Ameghino y sus implicancias en el conocimiento de los grandes mamiferos carnivoros del Mio-Plioceno de America de Sur

摘要

TAXONOMIC REVISION OF PARAHYAENODON ARGENTINUS AMEGHINO AND ITS IMPLICANCES FOR THE KNOWLEDGE OF THE MIO-PLIOCENE LARGE CARNIVOROUS MAMMALS OF SOUTH AMERICA. Parahyaenodon argentinus, from the Late Miocene-Early Pliocene of Monte Hermoso (Buenos Aires Province, Argentina), was recognized by Ameghino in 1904, who regarded it as Hyaenodontidae (Eutheria, Creodonta). Based on its dental features, later authors assigned P. argentinus to Borhyaeninae (Metatheria, Sparassodonta, Borhyaenidae). Thus, this taxon would have represented the last known borhyaenid. A new analysis of the type and only known specimen led us to reassign P. argentinus to Procyonidae (Eutheria, Carnivora). In this context, the biochron of Borhyaeninae extends up just to Late Miocene (Huayquerian Age), being cf. Borhyaena and possibly Eutemnodus the last known representatives of this subfamily. Based on these results and in the first records of carnivorous placenta! immigrants in South America, it is evident that there was no "competitive displacement" between metatherian and eutherian carnivores: there is a gap of no less than four Ma between the extinction of the last Borhyaeninae and the arrival of their alleged ecological counterparts, the Carnivora.