Article: The horse Cormohipparion theobaldi from the Neogene of Pakistan, with comments on Siwalik hipparions

A well-preserved skull of a three-toed horse, which is one of only a few known from the Neogene Middle Siwaliks of the Potwar Plateau, Pakistan, is referred to Cormohipparion theobaldi. This conclusion is based on cranial, dental, and size criteria that are diagnostic of this genus and species and differentiate it from the small Siwalik hipparions. The Siwalik hipparions appear to represent a polyphyletic assemblage of at least two, and probably three, forms. As a result of recent field work it is suggested, in contrast to previous hypotheses, that the 'Hipparion Datum' involves more than one form. The Siwalik hipparions have phylogenetic affinities with two or more groups in Holarctica. Cormohipparion theobaldi appears most closely related to other species of this genus found in Clarendonian (late Miocene) deposits of North America.