Subhyracodon (name meaning "Below Tooth") is an early relative of the Rhinoceros, It did not have a horn, so it relied on its running abilities and its tough skin. It was a herbivore eating mostly low plants.
In the Series 3 episode "The Big, the Bad, and the Ugly," several Subhyracodon were brought to the park from Late Oligocene North America, 24 million years ago. They reside in the Giraffe Enclosure.