ABSTRACT

We report on the Late Pleistocene (36–12 ka) mammals from Kibogo in the Nyanza Rift of western Kenya, providing (1) a systematic description of the mammal remains, (2) an assessment of their paleoenvironmental implications, and (3) an analysis of the biogeographic implications of non-analog species associations. Kibogo has yielded one of the largest paleontological assemblages from the Late Pleistocene of eastern Africa, and it is dominated by grassland ungulates (e.g., equids and alcelaphin antelopes), including an assortment of extralimital (e.g., Equus grevyi, Ceratotherium simum, Redunca arundinum) and extinct species (Syncerus antiquus, Damaliscus hypsodon, Megalotragus sp.). The composition of the fauna, in conjunction with the soils and topography of the region, indicate the local presence of edaphic grassland situated within a broader environment that was substantially grassier and likely drier than at present. In contrast to non-analog faunas from higher latitudes (e.g., North America and western Eurasia), the climatic niches of non-analog species associations strongly overlap, indicating that non-analog climate regimes during the Late Pleistocene of eastern Africa are not necessary to account for the former association of presently allopatric species. The Kibogo faunas add to a growing body of evidence implying that the composition of present-day African herbivore communities is distinct from those of the geologically recent past.

摘要

我们报告了肯尼亚西部Nyanza裂谷Kibogo地区的晚更新世（36–12 ka）哺乳动物，提供了（1）哺乳动物遗骸的系统描述，（2）对它们的古环境影响的评估，以及（3）非类比物种协会的生物地理意义分析。Kibogo取得了来自非洲东部的晚更新世最大的古生物组合之一，它是由草原有蹄类动物（如，马属动物和alcelaphin羚羊），包括extralimital的品种为主（例如，雅科仕grevyi，Ceratotherium simum，Redunca arundinum）绝种（Syncerus antiquus，Damaliscus hypsodon，Megalotragussp。）。动物区系的组成，再加上该地区的土壤和地形，表明当地存在埃达夫草原，这比现今的草场更为茂盛，可能更干燥。与高纬度地区（例如北美和欧亚大陆）的非类比动物区系相反，非类比物种协会的气候生态位强烈重叠，这表明东非晚更新世期间的非类比气候体制对于解释了目前同种异体物种之间的联系。Kibogo动物区系增加了越来越多的证据，这表明当今非洲的草食动物群落的组成与最近的地质情况截然不同。