Carnivora Id code: amd111Herpestidae Crossarchus obscurus F. G. Cuvier, 1825 (Eng) Cusimanse (Fre) Mangouste brune, crossarche brune Taxonomic notes It does not include C. platycephalus as stated by Goldman (1984, 1987), who separated central (C. platycephalus) from western monotypic (C. obscurus) African populations based on phenetic differences in skull proportions (Colyn & Van Rompaey, 1994). This separation, however, is still controversial (H. Van Rompaey, pers. comm.). IUCN threat category Not listed. Available information Most of the information available on the cusimanse derives from observation in captivity, and very few field studies have been conducted. Literature available is reviewed by Goldman (1984), where habitat, diet, and habits, as well as distribution are reported. Notes on its presence on Mount Nimba (Liberia) are found in Coe (1975); the author thoroughly describes the area surveyed, giving information on the habitat in which the species is found. General information on the species' ecology and distribution is found in Kingdon (1997) and in Stuart & Stuart (1997). The species' occurrence is accurately described in Goldman (1984). Known extent of occurrence  C. obscurus inhabits the rain forest zones between Sierra Leone and Nigeria (Ghana, Guinea, Ivory Coast, Liberia and Sierra Leone) (Wilson & Reeder, 1993; Colyn & Van Rompaey, 1994; Barnett et al., 1996). Fig 3.3.7.a was obtained from a map in Goldman (1987) and revised by Dr. H. Van Rompaey (20 May ‘97). At present there is no record of C. obscurus east of the Volta River in eastern Ghana or in the western Togo forest (Goldman, 1987). Categorical-discrete (CD) distribution model The species inhabits high forests, it is also associated to riparian forests (Goldman, 1987; Kingdon, 1997). Based on these environmental preferences, the following scores were assigned (Fig. 3.3.7.b) (3.3.7.a):
Tab 3.3.7.a: Cumulative size (km2) of areas pertaining to each environmental suitability class within the Extent of Occurrence.
Tab 3.3.7.b: Area of Occupancy fragmentation indexes. Probabilistic-continuous (PC) distribution model The output of the probabilistic-continuous (PC) distribution model is shown in Fig. 3.3.7.c. Validation No occurrence of the species within the four sample areas.
Comments and conservation issues The species is restricted to West Africa, where the known EO occupies less than 2 hundred thousand km2. According to the CD model, its AO is highly fragmented in a mosaic of suitable and moderately suitable patches; however, the total area available for the species occupies more than 90% of the EO and forms a large continuous area, as shown by the LPI value. The PC model output shows a similar but less fragmented pattern. The northern boundary of the known EO matches quite closely the suitable vegetation types limit; on the other hand, potential suitable areas west of the known boundary should be better investigated. Only 3% of the AO is included in existing protected areas, but the species is not considered endangered. However, considering its very restricted distribution range, and the tendency toward habitat deterioration indicated by the AO fragmentation pattern, this species status should be carefully monitored.
Tab 3.3.7.c: Percent of environmental suitability classes within EO (as obtained from the categorical-discrete distribution model) inside and outside the protected areas. References Barnett A.A., Prangley M., Hayman P.V., Diawara D., Koman J. (1996). A survey of the Mammals of the Kounounkan Massif, South-Western Guinea, West Africa. J.Afr.Zool.: 110, 235-240. Coe M.J. (1975). Mammalian ecological studies on Mount Nimba, Liberia. Mammalia: 39, 523-581. Colyn M.M., Van Rompaey H. (1994). A biogeographic study of cusimanses (Crossarchus) (Carnivora, Herpestidae) in the Zaire Basin. J.Biogeogr.: 21(5), 479-489. Goldman C.A. (1984). Systematic revision of the African mongoose genus Crossarchus (Mammalia: Viverridae). Can. J. Zool.: 62, 1618-1630. Goldman C.A. (1987). Crossarchus obscurus. Mammalian Species: 290, 1-5. Kingdon J. (1997). The Kingdon field guide to African Mammals. Academic Press, London and New York:Natural World. Stuart C., Stuart T. (1997). Field guide to the larger mammals of Africa. Struik Publishers. Wilson D.E., Reeder D.M. (Eds) (1993). Mammal Species of the World: A Taxonomic and Geographic Reference. Second edition. Smithsonian Institution Press, Washington D.C.
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