We're continuing our review of our collection of Pleistocene fossils from the Harveston neighborhood of Murrieta, in southwestern Riverside County. This is a diverse fauna with a number of different genera, but it appears that in terms of shear numbers of bones this collection is dominated by horses.The specimen shown here is a partial lower jaw of Equus occidentalis, including about 2/3 of the right dentary and a fragment of the left dentary at the mandibular symphysis. At the top is the lateral view, with anterior to the right. Below is the medial view, with anterior to the left:
And the dorsal view, also with anterior to the left, and showing the occlusal surfaces of the teeth:
The entire right dentition except for the incisors is preserved, from the 2nd premolar to the 3rd molar. These are all adult teeth, and they are all in wear, so this was an adult horse. In fact, in the lateral view at the top, we can see the unerupted part of the 3rd premolar. There is only a very short crown present above the root. Horses have teeth with extremely tall crowns, so possibly as much as 70-80% of this tooth has worn away. This horse was not just an adult, but was elderly (or, at least its teeth show an amount of wear typically only seen in elderly horses).