New data on the diversity and chronology of late Neogene sloths (Xenarthra, Folivora) from the Villavil-Quillay Basin, Catamarca, Argentina

Abstract

Folivora (Mammalia, Xenarthra) constitutes one of the most characteristic groups of mammals of the Cenozoic of South America, which is represented by several species within of Mylodontidae, Nothrotheriidae, Megatheriidae, and Megalonychidae. The diversity and biostratigraphical relevance of ground sloths recorded in the late Miocene–late Pliocene of Catamarca Province are studied here. The specimens studied come from new collections made in San Fernando Norte locality, and from museum collections from Puerta de Corral Quemado locality, both in Villavil-Quillay Basin, Belén Department, Catamarca Province (Argentina). The fossil record of ground sloths of Catamarca Province analysed here is expanded from the late Miocene to late Pliocene (Messinian to Piacenzian) and it is correlated with the biozones proposed for this basin. The record of the Megatheriinae Pyamidontherium sp. from San Fernando Norte confirms its presence in sediments younger than 5 Ma; the Nothrotheriinae Pronothrotherium typicum presents a very extensive record expanded for more than 3 Ma, and finally, the record of the genus Proscelidodon, represented by Proscelidodon gracillimus constitutes the oldest record of the genus.