Feeding habits and mobility of Equus conversidens and E. mexicanus from La Presita Blanca, State of San Luis Potosí, México

ABSTRACT

The aim of this study is to determine the feeding habits and home range of fossil horses (Equus conversidens and E. mexicanus) from La Presita Blanca, San Luis Potosí, central México. For this purpose, we used carbon, oxygen, and strontium isotope ratios. We compared ⁸⁷Sr/⁸⁶Sr from horses with strontium ratios of La Presita Blanca plants and soils to identify if these animals were local or came from elsewhere. The δ¹³C values indicate that E. conversidens specimen consumed C₄ plants and E. mexicanus was a mixed feeder. In this case, carbon isotopic values reflect only the animal’s feeding preferences and not the type of vegetation that existed in La Presita Blanca during the Pleistocene. Furthermore, δ¹⁸O values and strontium isotopic ratios show that E. conversidens was an animal that could be local to the Campo Volcánico de San Luis Potosí whereas E. mexicanus came from another region.

KEYWORDS:

• San Luis Potosí
• fossil horses
• stable isotopes
• ⁸⁷Sr/⁸⁶Sr
• diet
• mobility

Acknowledgements

We thank the Programa de Apoyo a Proyectos de Investigación e Innovación Tecnológica – UNAM for financial support (grants #IA104017 and #IA102719) for this study. Thanks to the Laboratorio Nacional de Geoquímica y Mineralogía/Laboratorio de Isótopos Estables of the Instituto de Geología, Universidad Nacional Autónoma de México, specially to Rafael Puente Martínez who helped with sample preparation and to Teodoro Hernández Treviño, from the Laboratorio Universitario de Geoquímica Isotópica LUGIS, who performed mechanical sample preparation. We thank Gerardo Arrieta García, from LUGIS, for conducting the isotopic measurements. Luis Peña Cruz, from the Departamento de Ciencias Ambientales y del Suelo – Instituto de Geología-LANGEM assisted with the FT-IR-ATR measurements. María Elena Sánchez-Salazar edited the first English manuscript. Miguel Morales Gomez for support in the drawing of Figure 1. Three anonymous reviewers provided important comments that improved the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Programa de Apoyo a Proyectos de Investigación e Innovación Tecnológica [IA102719, IA104017].