Notes on a finding of Megatherium sp. (Mammalia, Xenarthra, Megatheriidae) in the lower course of the Salado River (Region of Antofagasta, Chile)

Abstract

We present results of a taxonomic analysis of a mandible assigned to Megatherium sp. which was recovered from a secondary deposit on the fluvial north terrace in the lower course of the Salado River (Antofagasta Region, Chile). The comparison of the dimensions of the mandibular molariforms indicates that the Salado River specimen is smaller than M. americanum and larger than M. altiplanicum, being closer to the ranges of M. tarijense, M. sundti and M. medinae. Although the materials were collected from a collapsed block of a yet unidentified layer, sediments impregnated in the interstices of the bone, and in agreement with the stratigraphic distribution of the genus in other sites of the area suggest that the mandible comes from deposits of the Chiu-Chiu Formation (Upper Pleistocene and Upper Holocene).