On display in the “Extreme Mammals” traveling exhibit (seen at the Natural History Museum of Utah in Salt Lake City), it’s a fossil of Scarrittia Canquelensis:
Scarrittia lived around 30 million years ago in South America, during the early Oligocene epoch — back when South America was still attached to Antarctica. They were about 2 meters (6.6 feet) long, with a rhinoceros’ build (minus the horns). Apparently their defense against predators came from their bulk, since they were poorly adapted for running, and the shape of their leg bones made it hard for them to turn quickly.
Scarrittia was a very successful genus of the Leontiniidae family. This family prospered in South America until a major shift in climate occurred about 14.8 million years ago (coincident with the separation of South America from Antarctica), which led to a global wave of species extinctions.