Is the New Primate Genus Rungwecebus a Baboon?

Abstract

Our study clearly supports a close relationship between Rungwecebus and Papio and might indicate that the kipunji is congeneric with baboon species. However, due to its morphological and ecological uniqueness Rungwecebus more likely represents a sister lineage to Papio and experienced later introgressive hybridization. Presumably, male (proto-)kipunjis reproduced with sympatric female baboons. Subsequent backcrossing of the hybrids with kipunjis would have resulted in a population with a nuclear kipunji genome, but which retained the yellow/chacma baboon mitochondrial genome. Since only one kipunji specimen was studied, it remains unclear whether all members of the new genus have been impacted by intergeneric introgression or rather only some populations. Further studies with additional Rungwecebus samples are necessary to elucidate the complete evolutionary history of this newly-described primate genus.