Quelques caractéristiques écologiques du Singe des marais, Allenopithecus nigroviridisLANG 1923

Abstract

A one-month survey was carried out in Zaire in order to clarify the distribution of Allenopithecus nigroviridis and describe the main ecological features of the area. The species was abundant in the districts of Mbandaka, Géména, Mondombé and Lisala. Moreover it is known from the Kasongo-Lundo district : consequently its southern limit should be extended to 6° 30 S instead of the previously quoted limit of 3° S. Allenopithecus troops were observed in swamp forests near Mbandaka. Troops were large (more than 40 members) and had a multi-male structure. Their sleeping sites were situated on river banks and the same sites appeared to be occupied regularly. Allenopithecus troops associated with Cercopithecus ascanius troops. Moreover commensal troops are known near villages. These monkeys are semi-terrestrial and exhibit a strong size dimorphism in favor of males. Apart from these two latter characteristics, the main socioecological features of Allenopithecus are strongly reminiscent of those cf M. talapoin. The species composition of Cercopithecine communities living in inundated forests in N-E Gabon and Central Zaire are very similar. In both areas, Cercopithecus neglectus is abundant and equivalent species belonging to the same superspecies are generally found in each habitat. However in the study area, we did not find any member of the superspecies nictitans nor of Cercocebus galeritus, while A. nigroviridis seemed to replace M. talapoin. The local absence of the semi-terrestrial mangabey raises the question of its sympatry with Allenopithecus : although their distributions overlap extensively, the two* species may not in fact occupy the same habitat.