Almost all the species alive today were also around during the Ice Age. While they may have been filling different niches in the much more diverse Pleistocene fauna, their remains are very recognizable.
WSC has a small collection of fossils from Murrieta that include remains from a number of extant species. Among these are two associated forelimb bones from a deer, the humerus (above) and the radius (below, both in anterior view)
The humerus is missing the proximal 1/3 or so, but is otherwise in good shape. The radius is nearly complete except for a fragment at the distal end. While it’s difficult to see in these photos, there is some evidence of gnaw marks from rodents at the distal end of the humerus.
Both of these bones are from the left forelimb, and they articulate quite nicely (lateral view, with anterior to the left):
These bones are pretty much a perfect match for Odocoileus, the genus that includes the white-tailed deer and the mule deer. They are surprisingly small, however, and are a good bit smaller than the female white-tailed deer I was using as a reference. I’m not sure if this has any significance, since it’s difficult to draw generalized conclusions from a single specimen.