This Specimen has been sold.
8.3" Hyracodon (Running Rhino) Jaw Section - South Dakota
This is a beautiful, 8.3" long jaw section of Hyracodon nebraskensis. It was collected from the the Brule Formation in South Dakota and would be approximately 32-34 million years old. There are five teeth still embedded within the jaw. There are multiple repaired cracks throughout this jaw section, however there is no indication of any restoration.
Hyracodons were hornless running rhinoceroses with large heads compared to their slight, pony-like bodies. They are an extinct line as I'm sure you've noticed there are no Rhinos browsing the plains of North America today.