The early Vallesian vertebrates of Atzelsdorf (Late Miocene, Austria) 9. Hippotherium (Mammalia, Equidae)

The Hippotherium sample from the Vienna Basin, Austria, represents one of the geologically oldest collec­ tions of this equid genus in the Old World. This report presents new information from the locality of At­ zelsdorf, in conjunction with material previously known from Mariathal and Gaiselberg, also of Pannonian C (late Miocene) age. Whereas the number of specimens is small at some sites, collectively they show a dental morphology that is simpler and more plesiomorphic than that of Hippotherium primigenium from Eppelsheim or Howenegg, Germany, and also resembles material assigned to Cormohipparion sp. from North America. The new Atzelsdorf specimens improve our understanding of the morphology of the taxon that represents the earliest entry of Hippotherium into the Old World, here allocated to Hippotherium sp.