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. The researchers are members of the New York Consortium in Evolutionary Primatology, which groups biological anthropologists at Columbia, CUNY, NYU, the American Museum of Natural History and the Wildlife Conservation Society at the Bronx Zoo. The Consortium funds graduate students' training and research, and it contributed to the costs of Ms. Gonder's field work. Laboratory work was primarily supported by CERC's program in conservation genetics. 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.