Taxonomic and Functional Interpretation of Associated Cercopithecoid Carpal Bones (KB 5378) From Kromdraai B, South Africa

A partial carpus belonging to a large, South African Pliocene cercopithecoid was excavated from Kromdraai B (Gauteng, South Africa) between 1977 and 1981 alongside an associated late juvenile metacarpus and several manual phalanges (KB 5378). Included in the KB 5378 carpus is a partial scaphoid, lunate, os centrale, trapezium, trapezoid, capitate, and hamate. Here we describe each carpal bone quantitatively and qualitatively in comparison to a sample of extant anthropoid primates to gain an understanding of both functional morphology and taxonomy of the KB 5378 fossils. Overall, the carpal morphology reflects that of a generalized quadruped with potential specializations for terrestrial, digitigrade locomotion. The absolute size of the carpus and metacarpus indicate that they are likely from the same individual but are more similar in size to that of Papio or Parapapio rather than the larger Gorgopithecus major, as previously suggested.