Taxonomy and paleoecology of fossil Bovidae (Mammalia, Artiodactyla) from the Kibish Formation, southern Ethiopia: Implications for dietary change, biogeography, and the structure of the living bovid faunas of East Africa

• Kibish Formation yielded earliest fossils of Homo sapiens, ~ 196 ka.
• Kibish record shows significant range expansions of Late Quaternary bovids.
• Kibish fauna contrasts with sites from southern Kenya, deposited during periods of aridity.
• Kibish bovids are mesic-adapted; arid-adapted Quaternary forms are absent.
• Kibish fauna contrasts strongly with fauna from arid sites in southern Kenya.

The Kibish Formation of southern Ethiopia has yielded the earliest fossils of Homo sapiens, ca. 196 ka, and has thus figured prominently in discussions of the origins of modern humans. Here we describe the fossil Bovidae from the Kibish Formation, a record that spans the late Middle Pleistocene to the early to mid-Holocene, and reconstruct aspects of their dietary ecology using mesowear analyses. All of the Kibish bovids represent extant taxa with the exception of the extinct blesbok-like alcelaphin Damaliscus hypsodon; extinct arid-adapted forms Syncerus antiquus and Megalotragus, common in other Late Quaternary sites, are notably absent. Mesowear of the Kibish bovids suggests that the Late Quaternary specimens were characterized by diets with considerably more abrasion-dominated wear relative to their extant conspecifics. Finally, the Kibish record provides supporting evidence for recent phylogeographic hypotheses by demonstrating significant range expansions of Aepyceros melampus, Connochaetes taurinus, Hippotragus equinus, and, to a lesser extent, Kobus kob in the late Middle Pleistocene through the early to mid-Holocene coincident with humid phases that punctuated dry spells of the Late Quaternary.