First record of cf. Aenocyon dirus (Leidy, 1858) (Carnivora, Canidae), from the Upper Pleistocene of the Atacama Desert, northern Chile

Abstract

Fossil records of canids are rare and incomplete in South America. In Chile, all well-identified taxa are part of the "South American Canid Clade" and come from sites located in southern Patagonia. Here, we report the first record for Chile of a taxon of the "Canis clade," assigned to cf. Aenocyon dirus. The fossil remains consist of a partially complete left hind limb, exposed by aeolian deflation, which facilitated its discovery at an isolated setting in Quebrada Maní, named QM38 site, in the southern sector of the Pampa del Tamarugal basin, part of the hyperarid core of the Atacama Desert, northern Chile. Measurements of the fossil are larger than the Protocyon troglodytes, falling in the smaller size range of A. dirus and within the larger range of Theriodictis platensis. Its morphological features compared with bone references of large extinct canids show that the fossil belongs to a small-sized Aenocyon. The remains occur in surface silty clays deposited by an alluvial fan that was active in the Pampa del Tamarugal basin in the Late Pleistocene. A radiocarbon date from bone apatite yielded an age of 14,660 cal years BP, placing it within the first half of the Central Andean Pluvial Event when this basin was wetter, well vegetated, and inhabited by large, medium, and small herbivores. No other large predator records are known from this basin, and our find affords a more complete view of this ecosystem which thrived in the hyperarid core of the Atacama during the Late Pleistocene.