Una nueva localidad fosilífera en Oaxaca (México) y el registro más austral de Bison latifrons. Implicaciones paleobiogeográficas, paleoecológicas y paleoambientales

Abstract

We report the southernmost record of Bison latifrons in North America. This is the first record for the species in Oaxaca (Mexico), and for the Transmexican Volcanic Belt morphotectonic province; the known geographic distribution range of Bison latifrons is extended in more than 447 km, from Tequixquiac in the State of Mexico to central Oaxaca. This finding comes from a new fossiliferous locality at the municipality of San Dionisio Ocotepec, located in the Central Valleys region of the state of Oaxaca, Mexico. The associated fauna includes: Mammuthus columbi, Equus cf. E. conversidens, and Bison sp. By the presence of bison as well as mammoth, a Rancholabrean land mammal age (Late Pleistocene) is assigned to the fossil fauna. In addition, we performed a proboscidean mesowear analysis as well as a low magnification microwear analysis (35x) to the dental elements of the mammoth. Our findings suggest that the mammoth individual was a grazer. Due to the mammoth's feeding habits and the habitat described for Mexican samples of bison and horses, we concluded that during the Late Pleistocene, San Dionisio Ocotepec was dominated by open grassland in the lowlands. This new fossil site and its fauna contribute to improve the knowledge of the Rancholabrean in southern Mexico, and particularly in the Central Valleys of Oaxaca. This improves our understanding of the biotic and climatic changes during the foundation of the Holocene.

Nuevos registros de mamíferos Pleistocénicos de San Mateo Huexoyucán, Tlaxcala, y el segundo registro de juveniles de Mammuthus en México

“…Es interesante observar que esta combinación de megafauna sólo se presenta en la provincia morfotectónica de la Faja Volcánica Transmexicana (Ferrusquía-Villafranca et al, 2010). Recientemente se han reportado registros de Mammuthus en México para los estados de Baja California Sur (Rochín-Bañaga et al, 2017), Puebla (Carbot-Chanona et al, 2017) y Oaxaca (Viñas-Vallverdú et al, 2017;Díaz-Sibaja et al, 2018), pero la presencia de organismos juveniles de Mammuthus sólo han sido reportados en Tocuila, Estado de México (Morett et al, 1998;Arroyo-Cabrales et al, 2002), por lo que el registro en San Mateo Huexoyucán sería el segundo reporte para el país de organismos juveniles de Mammuthus (Figura 7). La presencia de ejemplares adultos y juveniles de Mammuthus sugiere el indicio de posibles manadas de mamuts en San Mateo Huexoyucán durante el Pleistoceno de Tlaxcala y estos ejemplares reflejan parte del potencial para estudios paleontológicos y geológicos futuros.…”

Species Diversity and Paleoecology of Late Pleistocene Horses From Southern Mexico

“…At present there are 23 main Pleistocene equid localities in Mexico (Sánchez Salinas et al, 2016;Priego-Vargas et al, 2017); of them, just five (21.73%) were previously reported from southern Mexico (Doutt and Black, 1962;Pérez Crespo et al, 2008;Priego-Vargas et al, 2017;Díaz-Sibaja et al, 2018a). In most of these reports, the equids are only mentioned or briefly described.…”