The oldest ape

Abstract

This paper recounts the history and significance of Morotopithecus bishopi, an early Miocene East African ape. Morotopithecus differs in intriguing ways from its contemporary Proconsul. While craniodental differences are slight, the known elements of its postcranium suggest that Morotopithecus was capable of modern ape–like positional behaviors, including vertical postures, deliberate climbing, and arm hanging. In contrast, Proconsul and other early and middle Miocene hominoids have been reconstructed as above–branch quadrupeds. Paleoanthropologists are currently divided over whether and which of the anatomical features associated with upright posture and suspension in the modern apes are due to inheritance or independent evolution. This debate has important implications for interpreting the phylogenetic positions of both Morotopithecus and Proconsul, as well as for reconstructing the pattern and timing of the emergence of modern ape adaptations.