A new species of Micropithecus from the middle Miocene of Kenya

Abstract

Recently recovered material of a small catarrhine primate from the middle Miocene locality of Maboko Island in Kenya (dated at 15–16 m.y.) can be referred to a new species of Micropithecus, M. leakeyorum. The dental differences between M. leakeyorum and the type species, M. clarki, suggest that M. leakeyorum was less specialised for frugivory than M. clarki, and probably included in its diet a greater proportion of young leaves or fruits of coarser consistency. This inference is concordant with a general shift in the diet of the catarrhine community from generalised frugivory during the early Miocene to an increased emphasis on folivory during the middle Miocene. This restructuring of the trophic and taxonomic composition of the primate paleocommunity is associated with an apparent increase in the occurrence of woodland habitats in East Africa, probably due to local tectonic events and possible also to global climatic changes. The recognition of a new species of Micropithecus from Maboko Island, along with other recent studies of the Miocene catarrhines from East Africa, demonstrates that middle Miocene apes were more diverse than had been previously thought. This finding has important implications for understanding the dynamics and evolution of the catarrhine community in East Africa during the early part of the Miocene.