Either result could require more aggressive conservation plans for the species, which is endangered throughout its range in sub-Saharan Africa. If further work confirms that the chimpanzees in Nigeria and western Cameroon are indeed a distinct subspecies, the anthropologists suggest that the correct name for it is Pan troglodytes vellerosus. Burton's skin may have come from the same subspecies as that discovered by the New York researchers. Field research was conducted in July and August of 1995 by Katy Gonder, a graduate student at the City University of New York and a research associate in Hunter College's Department of Anthropology. Three subspecies of common chimpanzee have been generally recognized, based on geographical, morphological and genetic criteria.
Pan troglodytes schweinfurthii in East Africa.
Though there are scattered groups of chimpanzees in Africa west of Ghana and east to Nigeria, all genetic samples of the verus subspecies prior to this study had come from west of Ghana, a factor that may account for their considerable genetic divergence from the others. The study found as much difference between the Nigerian chimps and the verus subspecies as between the two other recognized subspecies. That result, in itself, is not enough to declare a new subspecies, the researchers said, but it does throw the existing schema into question. If the Nigerian chimpanzees turn out not to be sufficiently different to be regarded as a distinct subspecies, then the other groups of central and eastern chimpanzees now recognized as subspecies should only be considered populations of Pan troglodytes troglodytes, they said. They propose two possible revisions to the existing schema, leaving either two or four subspecies.