Ogliocene, White River Formation, South Dakota.
This merycoidodont skull was fossilized with the mandible separated and pushed to the opposite side of the skull upper, which creates an interesting sculptural form. The skull has many intact teeth, but the skull is incomplete. In total, the fossil measures 11.25" at the longest point and 5.5" tall.
Oreodonts (aka "ruminating hogs"), were pig-like ruminating mammals who lived in what is now South Dakota approximately 30,000,000 years ago. There were two species; the Leptauchenia was a cat-sized aquatic animal, while the Merycoidodont was the size of a peccary and browsed on land.