Pliocene Antilocapridae (Mammalia: Artiodactyla) from San Miguel de Allende, Guanajuato, central Mexico

Abstract

The pronghorns Texoceros altidens, Subantilocapra garciae and a new specimen of Hexobelomeryx fricki are described. Fossil material was collected from Zanclean age sediments of the informal Rancho Viejo Beds of the San Miguel de Allende Graben, state of Guanajuato, in central Mexico. Analysis of teeth measurements of the four Texoceros species from North America revealed that they cannot be objectively identified, thus, they were synonymized with Texoceros altidens, which has priority. A mesowear analysis of the San Miguel de Allende teeth specimens showed that their mesowear scores are most similar to mixed-feeder and browser ruminants. A discriminant function analysis classified most of the Pliocene pronghorns from Guanajuato as mixed-feeders. Given the occurrence of Texoceros and Subantilocapra in the Hh3 of central Mexico, it is likely that the early evolution of the Recent pronghorn took place in central Mexico. The identified antilocaprid species from San Miguel de Allende, Guanajuato are the most southern records of Pliocene age in North America.