Mammuthus meridionalis (Proboscidea: Elephantidae) from the Borrego Badlands of Anza-Borrego Desert State Park ®, California: phylogenetic and biochronologic implications

A nearly complete skeleton of a mature female southern mammoth was recovered from the Borrego Badlands in Anza-Borrego Desert State Park®, California, USA. The remains represent a late evolutionary stage of the Mammuthus meridionalis (NESTI, 1825) chronocline, and constitute the most complete skeleton of this taxon in North America. Magnetostratigraphy and tephrochronology date the specimen at approximately 1.1 Ma BP. The osteology and osteometrics are presented herein. This late stage of Mammuthus meridionalis co-existed with an early evolutionary stage of M. columbi (= M. imperator of some authors). Significant morphological differences between the two taxa from the Borrego Badlands suggest that M. armeniacus rather than M. meridionalis was immediately ancestral to M.columbi. A dispersal of M. armeniacus to North America approximately 1.2 Ma BP is implied. At least two mammoth lineages (excluding Mammuthus primigenius) are seen in North America. An early M. meridionalis lineage and a later M. armeniacus - M. columbi lineage. M. meridionalis is recognized as the earliest species of mammoth in North America.