One thing has become quickly obvious as we’ve been examining the Harveston fossil collection: there are a lot of horses.
This is one of several isolated horse teeth from Harveston. This specimen is an upper right 1st molar, and is of particular interest because it is quite a bit smaller than most of our Harveston horses, as can be seen below:
It turns out there were actually two species of horses at Harveston. The larger and much more common one is Equus occidentalis, while the smaller, rare species is generally called Equus conversidens (there are some nomenclatural issues with this name and with Equus species in general, but I’m not going to get into that here). E. conversidens makes up perhaps 5% of the Harveston horses. This seems to be a general trend for southern California sites, including Diamond Valley Lake, with both species generally present, and E. occidentalis being much more common.
We’ve made a 3D scan of this E. conversidens tooth (WSC 24676) available for download on Sketchfab at https://skfb.ly/6yJNq.