COLLABORATIVE RESEARCH: Evolutionary History of Holarctic and Ethiopian Hipparionine Horses: Systematics, Lineage Extensions and Adaptations

University Of California-Riverside, Riverside CA

Investigators

Abstract

Hipparions are an extinct group of three-toed horses that flourished widely in the Old world shortly after their first occurrence there in the late Miocene, at about 11 Ma. Once established, hipparions evolved into a multitude of lineages with chronologic ranges extending to the middle Pleistocene in China and the late Pleistocene of Africa. The paleobiology of these horses within this great temporal (ca 10 m.y.) and geographic span has not been addressed systematically heretofore. PIs believe that hipparions actually originated within the North American genus Cormohipparion, but the actual species involved has not been demonstrated. Their proposed research will break new ground in 1. describing a complex pattern of speciation within Cormohipparion; 2. better resolving the Old World hipparion immigration and subsequent evolutionary radiation; and 3. unraveling the origin, evolutionary radiation, multiple geographic extensions and adaptation of species belonging to a distinctive Old World late Miocene Pleistocene radiation known as the Sivalhippus Complex. Once having described and documented the pattern of dispersal and diversification of hipparions in the Old World PIs will be able to investigate the paleobiology of these horses to gain further insights on the dietary and locomotory adaptations by which they achieved their predominance in this evolutionary theater for so long an interval of time.