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

河马是一种已经灭绝的三趾马，在中新世晚期，大约公元11世纪，它们首次出现在旧大陆后不久，就在旧大陆广泛繁衍。一旦建立，河马群就演变成许多谱系，其年代范围延伸到中国的中更新世和非洲的晚更新世。这些马在这个巨大的时间跨度（约10英里）和地理跨度内的古生物学迄今尚未得到系统的研究。pi认为，河马实际上起源于北美的Cormohipparion属，但实际涉及的物种尚未得到证实。他们提出的研究将在1.开辟新天地。描述了一种复杂的物种形成模式；2. 更好地解决了旧大陆河马迁徙和随后的进化辐射问题；和3。揭示了物种的起源、进化辐射、多重地理扩展和适应，这些物种属于一个独特的旧大陆中新世晚期更新世辐射，被称为Sivalhippus Complex。一旦描述和记录了东半球马的分散和多样化模式，pi将能够研究这些马的古生物学，从而进一步了解它们在进化舞台上如此长时间取得优势的饮食和运动适应。

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.