New records and diet reconstruction using dental microwear analysis for Neolicaphrium recens Frenguelli, 1921 (Litopterna, Proterotheriidae)

摘要

Neolicaphrium recens is the only survivor proterotherid in the Quaternary of South America, of which few fossil records from Argentina, Uruguay and probably Brazil are known. In this paper we describe new cranial remains with teeth series of N. recens from Artigas Department, Uruguay (Sopas Formation, Late Pleistocene), and previously published remains were reinterpreted and assigned to N. recens. We performed a dental microwear study of the seven most complete adult specimens from Argentina and Uruguay. The dental facets of interest were molded with silicone dental impression; the moulds were filled with epoxy resin and observed in a stereomicroscope. The paracone of M2 and the protoconid of m2 were photographed and the images digitally processed and studied. The results showed a high relative percentage of pits (scars of soft plants) on scratches (grooved pattern caused by silicophytoliths of grasses), indicating that the analyzed specimens were browsers, and their diet probably included fleshy leaves, buds and stems of trees and shrubs. These new data are consistent with previous results of carbon and oxygen isotopes studies and with inferences based on the associated fauna of N. recens in Uruguay, indicating for the Sopas Formation open to semi open grassland with forested areas, resembling a savanna. This study suggests some woodland environments for all the range of geographical distribution of the taxon.