A new species of Proconsul from the early Miocene of Rusinga/Mfangano Islands, Kenya

The species Proconsul africanus from the early Miocene of East Africa has long been recognized from Koru (the type locality), Songhor, Rusinga Island and Mfangano Island. Comparison of the type series from Koru with specimens from Rusinga and Mfangano indicates that this material does not belong to a single species. The material from Koru and from Songhor belongs to a single species that takes the name P. africanus and which is not represented at Rusinga or Mfangano. The Rusinga and Mfangano material exhibits levels of metric variation in the teeth and postcranial skeleton that are incompatible with its recognition as one species. The larger species at Rusinga and Mfangano takes the name Proconsul nyanzae. The smaller species does not have a name available for it and is described here as a new species, Proconsul heseloni.