This image is of a Subhyracodon occidentalis rhino skull fossil on display at Mace Brown Museum of Natural History (August 2017). The animal it belonged to is a cow sized extinct hornless rhino-like creature. It dates to the Early Oligocene Epoch (about 33 million years ago). The fossil was found in Pennington County South Dakota USA.
The Mace Brown Museum of Natural History is located at the College of Charleston, 202 Calhoun Street, 2nd Floor, Charleston, South Carolina 29424.
Learn more at their blog: http://blogs.cofc.edu/macebrownmuseum/