Equidae from the Baynunah Formation

We report 87 specimens of hipparionine horse from the Baynunah Formation, United Arab Emirates. The dominate species is referred to “Hipparion” abudhabiense. “Hipparion” abudhabiense is represented by mandibles, mandibular and maxillary cheek teeth and a variety of postcranial bones, some of which are complete. Baynunah Formation early wear cheek teeth suggest that “Hipparion” abudhabiense was higher crowned than Central European Hippotherium primigenium with a maximum crown height of 60-65 mm. AUH 270, the type mandible is characterized as having a short, broad symphysis with horizontally aligned incisors. While the previous view was that this mandible suggested an evolutionary relationship with Greek Hipparion dietrichi, a fragmentary but otherwise elongate metacarpal III (AUH 1499) exhibits a close similarity to Akkasdagi (7.1 Ma) and Calta (4.0 Ma) “Plesiohipparion” cf. longipes. There is a rare, smaller species of hipparion that compares favorably in its size and morphology to Greek and Iranian members of the Cremohipparion matthewi-nikosi lineage. The Baynunah hipparion fauna supports a correlation of ca. 7 Ma, and a potential biogeographic affinity with Greece, Turkey, Iran and possibly Northern Kazakhstan.