Environmental inferences based on the dietary ecology of camelids from west-central Mexico during the Late Pleistocene

Fossil camelids (Artiodactyla, Camelidae) record for Mexican Late Pleistocene is constituted by Camelops hesternus, Hemiauchenia macrocephala, Hemiauchenia gracilis, and Palaeolama mirifica. It analysed dental microwear and carbon and oxygen stable isotopes in teeth enamel of C. hesternus, H. macrocephala and H. gracilis from two fossil sites (LC-PT, and LP-SA) in west-central Mexico, gaining knowledge about camelids palaeoecology (diet and habitat). Microwear and δ13C values indicate that C. hesternus from both sites had a browser diet with a preference for C3-C4 plants, while H. macrocephala from LC-PT was browser with a predilection for C3 plants, and H. gracilis from LC-PT had a mixed feeder diet with a preference for C3 plants. The δ18O and the aridity index show that camelids in central Mexico were evaporation-sensitive taxa. The results suggest that LC-PT had a heterogeneous environment composed of open areas and closed zones, temperatures between 13.95°C and 19.9°C and extreme seasonal changes. The environment in LP-SA was dominated by open areas, with small closed vegetation patches, a temperature of 16.29°C, and less seasonal variation. The aridity index indicates relatively drier conditions at LP-SA than at LC-PT. Camelid dietary ecology provides an initial reconstruction of a regional paleoenvironment, with diverse ecosystems present.