There are three primate taxa which have the same range in West Africa (eastern Ivory Coast and western Ghana): Miss Waldron’s red colobus Piliocolobus badius waldronae, the Roloway guenon Cercopithecus diana roloway and the white-naped mangabey Cercocebus atys lunulatus. They were previously listed as critically endangered; however, Cercocebus atys lunulatus was recently downgraded to endanger. A series of surveys have been conducted since the early 1990s in the tropical forests of Ghana and Ivory Coast to survey thesee taxa.
citation: Bi SG, Bené JCK, Bitty EA, Kassé BK, Guessan AN, et al. (2013) Roloway Guenon (Cercopithecus diana roloway) and White-Naped Mangabey (Cercocebus atys lunulatus) Prefer Mangrove Habitats in Tanoé Forest, South-Eastern Ivory Coast. J Ecosys Ecograph 3: 126.