Roloway Guenon, Cercopithecus diana roloway - Top 25 Most Endangered Primates

Illustration © 2007 by Stephen Nash. Roloway Guenon
Cercopithecus diana roloway (Schreber, 1774)
Ghana and Côte d’Ivoire
(2002, 2006)
One of the most beautiful of West Africa's monkeys, the Roloway guenon is targeted by the voracious bushmeat trade, and is vanishing from forest reserves throughout its limited range.

There are two subspecies of Cercopithecus diana, both highly attractive, arboreal monkeys that inhabit the Upper Guinean forests of West Africa (Grubb et al. 2003). The Roloway subspecies is distinguished by its broad white brow line, long white beard and yellow thighs. Groves (2001) considers the two subspecies to be sufficiently distinct to be regarded as full species. Of the two forms, the Roloway, which is known from Ghana and eastern Côte d’Ivoire, is more seriously threatened with extinction. In fact, along with the white-naped mangabey (Cercocebus atys lunulatus) and Miss Waldron’s red colobus (Procolobus badius waldroni), it is among the three most endangered monkeys of the Upper Guinea forest block and a target species of the relentless bushmeat trade (Oates 1996).
As primatologists search the tropical forests of Ghana and Côte d’Ivoire for evidence of living red colobus, they are also documenting the continued decline of both the Roloway guenon and white-naped mangabey, which seem to be found in and to be absent from many of the same forests (Struhsaker and Oates 1995; Oates et al. 1996/1997; McGraw 1998a; Kone 2004; Oates 2006). In Ghana, Roloway guenons have been steadily extirpated from both unprotected and protected areas (for example, Bia National Park) and the monkey is nearing extinction in that country if it has not disappeared already.
Very recent surveys failed to confirm the presence of Roloways in four reserves in western Ghana including one—Krokosua Hills Forest Reserve—believed to harbor the monkey only several years earlier (Magnuson 2003; Oates 2006). It is possible that Ankasa Resource Reserve still contains a few Roloway individuals (Magnuson 2003), but in 2006 a wildlife guard reported to J. Oates (unpublished) that he had not seen the monkey for several years. A thorough new survey of Ankasa, and of the Dadieso Forest Reserve (where the monkey was also reported in the recent past) should be a high priority.
In neighboring Côte d’Ivoire, the Roloway guenon is not known from any protected areas and the monkey’s status is equally dire. Surveys made ten years ago documented Roloways in two forests: the Yaya Forest Reserve and wet forest adjacent to the Ehy Lagoon (McGraw 1998b, 2005). Field surveys made in 2004 failed to document Roloways at additional sites in southern Côte d’Ivoire (Kone and Akpatou 2005) although hunters indicate that Roloways are present in small numbers in the Parc National des Iles Ehotilé (Kone and Akpatou 2005). Intensive and systematic primate inventories must be carried out at both Ehotilé and Ehy.

W. Scott McGraw & John F. Oates

References
Groves, C. P. 2001. Primate Taxonomy. Smithsonian Institution Press, Washington, DC.
Grubb, P., T. M. Butynski, J. F. Oates, S. K. Bearder, T. R. Disotell, C. P. Groves and T. T. Struhsaker. 2003. An assessment of the diversity of African primates. Int. J. Primatol. 24: 1301–1357.
Kone. I. 2004. Report on recent primate surveys in the southeast of Ivory Coast. Report, Conservation des Espèces et des Populations Animales (CEPA), Schlierbach, France.
Kone, I. and K. B. Akpatou. 2005. Recherche en Cote d’Ivoire de trios singes gravement menaces d’extinction. CEPA Magazine 12: 11–13.
Magnuson, L. 2003. Final Brief: Ecology and Conservation of the Roloway Monkey in Ghana. Unpublished report to the Wildlife Division of Ghana, Forestry Commission, Ghana.
McGraw, W. S. 1998a. Three monkeys nearing extinction in the forest reserves of eastern Cote d’Ivoire. Oryx 32: 233–236.
McGraw, W. S. 1998b. Surveys of endangered primates in the forest reserves of eastern Cote d’Ivoire. African Primates 3(1–2): 22–25.
McGraw, W. S. 2005. Update on the search for Miss Waldron’s red colobus monkey (Procolobus badius waldroni). Int. J. Primatol.26(3): 605–619.
Oates, J. F. 1996. African Primates: Status Survey and Conservation Action Plan. Revised Edition. IUCN/SSC Primate Specialist Group, Gland, Switzerland. 80pp.
Oates, J. F. 2006. Primate Conservation in the Forests of Western Ghana: Field Survey Results, 2005–2006. Report to the Wildlife Division, Forestry Commission, Ghana.
Oates, J. F., T. T. Struhsaker and G. H. Whitesides. 1996/1997. Extinction faces Ghana’s red colobus and other locally endemic subspecies. Primate Conserv. (17): 138–144.
Struhsaker, T. T. and J. F. Oates. 1995. The biodiversity crisis in southwestern Ghana. African Primates 1: 5–6.

Suggested citation:
McGraw, W. S. and Oates, J. F. 2007. Roloway Guenon, Cercopithecus diana roloway. In: Primates in Peril: The World’s 25 Most Endangered Primates 2006–2008, R. A. Mittermeier et al. (compilers), p.8. Unpublished report, IUCN/SSC Primate Specialist Group (PSG), International Primatological Society (IPS), and Conservation International (CI), Arlington, VA.