Plesippus is a genus of extinct horse from the Pleistocene of North America. Although commonly seen as a subgenus of Equus recent cladistic analysis considers it a distinct genus.
Species Two species are recognized by Barron et al. (2019), P. simplicidens and P. idahoensis.
References
The Hagerman Horse Quarry Hagerman Fossil Beds' Critter Corner - Hagerman Horse - Equus simplicidens, Dr. Greg McDonald