New Remains of Middle Miocene Equids From the Cajon Valley Formation, San Bernardino National Forest, San Bernardino County, California

Abstract

Barstow Formation While similar in time and nearby geographically, some Cajon Valley Formation and Barstow Formation fauna are exclusive of each other, which might have implications for the Miocene paleoecology of both areas. Chalicotheres "Parahippus" brevidens Scaphohippus sumani Scaphohippus sumani LARGE-BODIED SMALL-BODIED Archaeohippus mourningi Comparatively rare No occurrence Hypohippus affinis and Megahippus mckennai Cajon Valley Formation Ecological Implications References Acknowledgements The genus Scaphohippus, named by Darrin Pagnac in 2006, currently consists of two species: S. sumani and S. intermontanus, both of which were originally included in the genus Merychippus (Merriam 1915). Both species overlap in time. Furthermore, we propose that previously cited differences in plication morphology and wear patterns are not sufficient to distinguish two taxa. We assert that based on observed full palates of both species, there is actually only one species: Scaphohippus sumani, which has taxonomic priority.