Date of this Version
Well-preserved teeth and jaw fragments of a very small but extremely hypsodont horse referable to Calippus regulus are described from the Penny Creek Local Fauna of Early Clarendonian age in south-central Nebraska. The species has previously been reported only from Texas, with possible occurrences in Oklahoma and Florida. Specimens from the Late Clarendonian of northern Nebraska previously referred to Calippus placidus appear to be similar to the Penny Creek specimens. C. placidus is probably confined to older, Late Barstovian, rocks.