Miocene Hominoids and Hominid Origins

Abstract

Recent discoveries have greatly clarified the family tree relationships of Miocene apes to modern apes and humans. Contrary to most previous interpretations, new fossil evidence indicates that well-known middle-late Miocene large-bodied apes such as Kenyapithecus, Sivapithecus, and Dryopithecus branched off before the ancestor that gave rise to all living hominoids; therefore, these extinct genera are not members of the great ape and human grouping. Jaw and tooth features that Miocene large-bodied apes share with great apes and humans can now be regarded as conservative retentions from the ancestral condition for living apes, including gibbons. The first appearance of these great ape-like features in the African middle Miocene is correlated with an adaptive shift to consumption of hard fruit and nuts. Although the transition from life in the trees to life on the ground is deeply embedded in models of human evolution as a primary motive force in human origins, among African large-bodied apes this change occurred approximately 15 million years ago and is not directly linked with the advent of bipedalism or colonization of grassland environments 3-4 million years ago.