Milne-Edwards, 1886

(Fre) Cercocèbe agile

In accordance with Wilson & Reeder (1993) this species is considered distinct from C. galeritus and includes the subspecies: C. a. chrysogaster (Golden-bellied mangabey) in former Zaire and C. a. sanjei (Sanjei crested mangabey) in Tanzania. Baillie & Groombridge (1996) and Oates (1996) still maintain the original classification.

Lower Risk, near threatened (LR: nt) as C. g. agilis, but Endangered (EN: criteria B1+2c) as C. g. sanjei and Data Deficient (DD) as C. g. chrysogaster.

The species’ ecology has been poorly studied. Notes on its ecology in north-east Gabon are found in Quris (1975). Some information on the habitat in which it occurs is reported in Bourlière (1985), Colyn (1988) and Homewood & Rodgers (1981), while Gautier-Hion & Gautier (1986) focus on behavioural aspects of the species’ ecology. The species’ presence has been thoroughly surveyed in parts of former Zaire (Colyn, 1988), Congo and Cameroon (Mitani, 1990). Status and threats are discussed in Lee et al. (1988); the authors also give some information on the species’ ecology. General information on the biology of the species is found in Kingdon (1997).

Known extent of occurrence

This species ranges in Eq. Guinea, Cameroon, north-east Gabon, south C.A.R., north Congo Republic and former Zaire (Wilson & Reeder, 1993). The newly discovered sanjei form is endemic to a small area around the Uzungwa Mts. in Tanzania (Lee et al., 1988). The southern limits have been identified as the watershed between the Aruwimi and Lindi Rivers (Colyn, 1988). Fig. 2.3.2.a was obtained from Groves (1978) and revised on the basis of both the river network and the new map in Kingdon (1997).

This species is associated to swamp, riparian and seasonally flooded forests (Bourlière, 1985; Kingdon, 1997).

Based on these environmental preferences, the following scores were assigned (Fig. 2.3.2.b) (Tab. 2.3.2.a):

The output of the probabilistic-continuous (PC) distribution model is shown in Fig. 2.3.2.c.

The known EO of this species is divided into three separate portions, inhabited by different subspecies. According to the CD model, which is amply supported by the validation parameters (Index of Accordance = 70%), its AO in central Africa, on both sides of the Zaire River, is largely suitable and interconnected, as shown by the NP and LPI, while the quite separate portion in Tanzania is apparently mostly unsuitable, confirming the endangered status of the sanjei form. The PC model confirms this general pattern, though indicating better suitability values in the southern portion of the main range. Moreover, it clearly shows low suitability peaks matching major cities. About 7% of the AO is included in existing protected areas; the Uzungwa National Park appears essential for the survival of the Sanjei crested mangabey, while further research is needed to clarify the distribution, taxonomy and conservation status of the species in the central forest block.