It’s springtime, and in the Inland Empire that means snakes! The Pleistocene fossils from Southern California make it clear that this has been the case for a long time, as demonstrated by the vertebra shown above.
This partial vertebra is probably from the genus Crotalus, a rattlesnake, shownfrom the front (anterior view). Snake vertebrae are procoelous, meaning that the vertebrae articulate with each other with a ball-and-socket joint with the socket on the front of the vertebra; the socket is clearly visible in the image above.
Snakes have a lot of vertebrae, up to several hundred in some species, so each individual vertebra is typically not very big. This vertebra is a little over a centimeter across, which represents a pretty large rattlesnake.