An updated taxonomic view on the family Gomphotheriidae (Proboscidea) in the final Pleistocene of south-central Chile

摘要

There is an abundant fossil record of the family Gomphotheriidae in Chile, which is en-tirely ascribed to the late Pleistocene. Despite this, the lack of taxonomically diagnostic material has lead to an extended discussion, which has not reached a consensus regarding the number of forms of gomphotheres effectively present. This paper discusses the taxonomy of Chilean gomphotheres, based on tooth morphology and biometry, paleoecological and biogeographical data. The morphol-ogy of the tusks indicates the presence of the Stegomastodon genus in Chile, while bivariate and multivariate analyses of the teeth show an important amount of variability within the studied sample, although with a tendency towards larger sizes for the genus Stegomastodon and the Chilean samples than for Cuvieronius, especially among the M3s and m3s. In spite of this, in this paper only the specimens from localities that yielded molars associated with tusks are assigned to the genus Stego-mastodon. Biogeographic information is consistent with the presence of a lowland-adapted taxon such as Stegomastodon, which could have reached the Chilean territory either through an Andean corridor from Argentina, or through a low-altitude route from Peru, then by the northern region of Chile. Bibliographic isotopic data also indicates an adaptative change to C3 feeding along a latitudinal gradient, around 35-41°S, which makes the Chilean and south Argentinean results quite similar at these latitudes. Due to the metric variability observed, the Chilean samples could not be assigned to individual species.