Among the large animals recovered during the Diamond Valley Lake excavation, fully 1/5 of the specimens came from horses; only bison bones were more common among the large animals. There are two species of horse represented at DVL. The smaller species, Equus conversidens, is exceptionally rare in the deposit, and nearly all the recovered specimens belong to the larger Equus occidentalis. Reflecting this, there are a number of E. occidentalis skulls in the WSC collections.
The specimen shown above is a partial skull of E. occidentalis seen in ventral view, with anterior to the right. The incisors are missing, but otherwise the right dentition is almost complete. The right teeth are labeled below:
The only bones visible in this view are the maxillae, which hold the teeth, and a small part of the palatines, which form the curve at the posterior end of the palate (on the left in this image). That curve also forms the front edge of the interior nares, where the nostrils pass through the skull.
This individual was an adult horse, with all of its permanent teeth erupted and showing wear. It was recovered from the West Dam area, which includes the most recent Pleistocene deposits in DVL. Carbon dates on samples from the West Dam area were all less than 20,000 years old, and most were less than 14,000 years (Springer et al. 2009).
Springer, K., E. Scott, J. C. Sagebiel, and L. K. Murray, 2009. The Diamond Valley Lake Local Fauna: Late Pleistocene vertebrates from inland Southern California. In L. B. Albright III (ed.), Papers on Geology, Vertebrate Paleontology, and Biostratigraphy in Honor of Michael O. Woodburne. Museum of Northern Arizona Bulletin 65:217-235.