New perspectives on middle Pleistocene change in the large mammal faunas of East Africa: Damaliscus hypsodon sp. nov. (Mammalia, Artiodactyla) from Lainyamok, Kenya

In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: New perspectives on middle Pleistocene change in the large mammal faunas of a b s t r a c t a r t i c l e i n f o The middle Pleistocene fossil mammal assemblage from Lainyamok in the southern Kenya rift has previously been considered the oldest (330–392 ka) African mammal community consisting entirely of extant species, with the dominant bovid tentatively attributed to the southern African blesbok (Damaliscus cf. dorcas). We show that the blesbok-like fossils from Lainyamok belong to an extinct species, described here as Damaliscus hypsodon sp. nov. The D. hypsodon hypodigm includes the previously unnamed small alcelaphine material known from late Pleistocene sites elsewhere in Kenya and Tanzania. Its dental anatomy, together with an ecomorphological analysis of its postcrania, indicates that D. hypsodon grazed in open and arid grassland environments. Although Lainyamok is no longer represented entirely by extant species, the absence of species common earlier in the middle Pleistocene of East Africa suggests substantial faunal turnover between 500 and 400 ka. Damaliscus hypsodon persisted in East Africa until the end of the Pleistocene and its extinction can be attributed to a loss of arid grassland environments at the onset of the Holocene. The fossil evidence from southern Kenya suggests that the development of the taxonomically modern large mammal community was a long-term process characterized by the extinction of grazing specialists, with marked turnover occurring between ~500 and 400 ka and near the end of the Pleistocene. Dating to between 330,000 and 392,000 years ago, the faunal assemblage from Lainyamok in the southern Kenya rift (Fig. 1) is regarded as the oldest well-sampled African mammal community consisting entirely of extant species (Potts and Deino, 1995). The absence of extinct taxa typical of earlier East African sites (780,000 to 500,000 years ago), including the suid Kolpochoerus majus, the giant cercopithecid Theropithecus oswaldi, the elephantid Elephas recki,, implies substantial faunal turnover during the middle Pleistocene. At the same time, Lainyamok is atypical of subsequent late Pleistocene sites in East Africa, here several extinct bovid species (e.g., long-horn buffalo (Syncerus antiquus), giant wildebeest (Megalotragus sp.), Rusingoryx atopocranion, and a small alcelaphine) are well documented and sometimes …