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 <i>Camelops hesternus, Hemiauchenia macrocephala, Hemiauchenia gracilis</i>, and <i>Palaeolama mirifica</i>. It analysed dental microwear and carbon and oxygen stable isotopes in teeth enamel of <i>C. hesternus, H. macrocephala</i> and <i>H. gracilis</i> 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 <i>C. hesternus</i> from both sites had a browser diet with a preference for C₃-C₄ plants, while <i>H. macrocephala</i> from LC-PT was browser with a predilection for C₃ plants, and <i>H. gracilis</i> 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.