A newCormohipparion(Mammalia, Equidae) from the Pliocene (latest Hemphillian and Blancan) of Florida

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Abstract
Cormohipparion emsliei n. sp. is documented from the latest Hemphillian and late Blancan of peninsular Florida. This extends the known temporal range of the genus in North America by about four million years. C. emsliei continues and accentuates many of the trends observed in earlier species of Cormohipparion, including increased fossette complexity (on average it is the most complicated of North American hipparionines) and pli caballinid development on both premolars and molars. The dorsal preorbital fossa is reduced, as is frequently observed in late Neogene equids, but a number of shared derived characters suggests referral to Cormohipparion rather than Nannippus. The topotypic sample, which includes cranial and post-cranial elements, was collected in situ from a narrow horizon under- and overlain by diverse marine shellbeds of Pliocene age. It was found in lithosympatry with specimens of Nannippus peninsulatus, Neochoerus dichroplax, Glossotherium chapadmalense, Dasypus bellus, and Sigmodon medius. Their combined presence indicates a late Blancan age. C. emsliei is the descendant of the earlier Hemphillian species Cormohipparion ingenuum, also known from Florida, and possibly represents a relictual taxon limited to the Gulf Coastal Plain.