New wrist bones of Proconsul africanus and P. nyanzae from Rusinga Island, Kenya.

The anatomy of the wrist of two species of the early Miocene hominoid Proconsul is described based on new material collected on Rusinga Island, Kenya. These fossils generally confirm previous findings that the wrist of Proconsul is monkey-like in much of its morphology. However, the structure of the ulnar side of the wrist, particularly the ulnocarpal joint, is significantly different from that of extant monkeys and suggests some functional affinities with extant hominoids. Thus the wrist of Proconsul is neither monkey-like nor ape-like in its total morphology. Instead, it shows a unique combination of features which once again point to the oversimplicity of forcing fossil forms into categories based only on extant taxa.