Environmental correlates of the cercopithecoid radiations.

Modern Old World monkeys live in an array of habitats, an ability that was established early in their evolutionary history. The Old World monkey radiation is commonly correlated with the general trend of climatic cooling in the Neogene and the associated increase in open habitats. However, although they became more abundant and speciated extensively in the very late Miocene, Pliocene and Pleistocene, many of the major events in cercopithecoid evolution occurred before the onset of the late Miocene long cooling period. In the Plio-Pleistocene, regional environmental change and interspecific competition probably influenced the radiations of the Old World monkeys in Africa much more than did global climatic patterns. In southern Africa, the evolution of the monkey community is tied to Pleistocene increases in grassland and open habitats. In East Africa, the more diverse cercopithecid fauna reflects the presence of a wider variety of habitats, including forest, woodland and grassland.