The sabre-toothed cat Smilodon fatalis Leidy, 1868 (Felidae, Machairodontinae) in the late Pleistocene-early Holocene of South America (Dolores Formation, Uruguay): New insights about its paleodistribution, taxonomy and status of the genus

The sabre-toothed cat Smilodon fatalis was an iconic predator in the Americas during the Ice Age. While its distribution in North America is abundant, its record in South America is very scarce and is restricted to only a few locations. In the present contribution a new skull assigned to Smilodon fatalis is described. The specimen comes from the Dolores Formation (late Pleistocene-early Holocene, Lujanian Stage/Age) in southern Uruguay. This skull is elongated and narrow in its general shape; its nasals are not markedly high and, in the posterior part, the large lambdoid crest is anteroventrally straight, converging in the same plane with the mastoid process, characteristics observed in S. fatalis that clearly differentiate it from S. populator. Body mass estimations, according to allometric equations for extant felids, and the quantitative analyses (bivariate graphs) provide results consistent with the aforementioned taxonomic assignment. Based on this finding, which turns out to be, to date, the southernmost record for this species in the Americas, some paleobiogeographic and taxonomic implications in a regional context are discussed.