Allenopithecus nigroviridis (Pocock, 1907)

Russell A. Mittermeier, Anthony B. Rylands & Don E. Wilson, 2013, Cercopithecidae, Handbook of the Mammals of the World – Volume 3 Primates, Barcelona: Lynx Edicions, pp. 550-755 : 668-669

46.

Allen’s Swamp Monkey

Allenopithecus nigroviridis

French: Cercopithéque d'Allen / German: Sumpfmeerkatze / Spanish: Mono de Allen

Other common names: Swamp Guenon, Swamp Monkey

Taxonomy. Cercopithecus nigroviridis Pocock, 1907 ,

Upper Congo.

Molar flare and ischial callosities that fuse across the midline are two physical conditions unique to the genus Allenopithecus among Cercopithecini , but they are shared with some,if not all, Papionini . Another feature common to most Papionini is the periodic sexual swelling of females, shared only with Miopithecus among the Cercopithecini . Recent molecular studies suggest a tribal affiliation of Allenopithecus with the Cercopithecini rather than the Papionini . It is the sister taxon ofall the Cercopithecini . Monotypic.

Distribution. NW DR Congo and NE Republic of the Congo, in lowland forests of the Congo Basin on both sides of the lower and middle Congo (c.16” E to 26°-27° E); S of the Congo Riverits distribution extends E to the Lomami River system (c.3° N to 6° 30° S); it has also been recorded on twoislands in the Sangha River. Its presence in NE Angola requires confirmation.

Descriptive notes. Head-body 45-50 cm (males) and 40-45 cm (females), tail 51 cm (males) and 36 cm (females); weight 5.9-6.1 kg (males) and 3.2-3.7 kg (females). Male Allen’s Swamp Monkeys are larger than females. They are very robust, with short limbs, a relatively short tail, and broad hands and feet. They have pointed macaquelike ears and a dark face, with pale, off-white eyelids and chin. Facial hair is agouti black-yellow, giving a dark olive—green effect; it is especially long on cheeks and forms a circular face mask bordered with narrow black eyebrow bands extending back to ears. Crown appears like a broad, flattened cap. Underside is grayish, off-white, slightly speckled; throat is gray but not speckled. Male perineum has a red margin and an orange perineal tuft; scrotum is bluish white. Males have a scent gland on their chest that is marked by bristly white hair. Digits on feet are long and powerful, and hands are shorter and broader than is typical of guenons. Neonatal coatis yellow-brown, with an almost white crown.

Habitat. Swamps in lowland moist forests, bordering lakes and rivers that are seasonally flooded. Allen’s Swamp Monkey is largely arboreal when the forest is flooded but more terrestrial when flooding recedes. It is also found in mangroves and occasionally enters terra firma forests and more open formations. It enters fields to raid crops.

Food and Feeding. A study of Allen’s Swamp Monkeys in 1985 reported a diet of 81% fruit, 17% invertebrate prey, and 2% miscellaneous items such as flowers, nectar, pith, and roots. They lick nectar of, and thereby pollinate, Daniellia pynaertii ( Fabaceae ) flowers. They also eat crabs and scoop fish out of muddy pools during the dry season.

Breeding. Births of Allen’s Swamp Monkeys have been recorded throughout the year. Life span is estimated to be 28 years.

Activity patterns. Allen’s Swamp Monkeys are diurnal and semi-arboreal-semi-terrestrial. Locomotion is quadrupedal, with climbing and leaping. They use the lowerstrata of the forest canopy and often forage on the ground. They can swim and will dive into a river to avoid predators,or flee on the ground rather than climb to safety. They sleep in trees 8-20 m above the ground along river edges and lake borders.

Movements, Home range and Social organization. Home range sizes and the lengths of the daily movements of Allen’s Swamp Monkeys are unknown. They live in multimale-multifemale social groups of 23-57 individuals, but it is possible that the social organization is one of harems. Groups of 2-8 individuals tend to travel and forage together. Single males may travel separately during the day but join up with the group at night. They produce baboon-like grunts as they travel and also guenon-like, highpitched alarm chirps.

Status and Conservation. CITES Appendix II. Classified as Least Concern on The [UCN Red List. Allen’s Swamp Monkeyis listed as Class B in the African Convention on the Conservation of Nature and Natural Resources. They are hunted from boats on rivers at night as they sleep in trees overhanging the river, but hunting is not believed to be so serious that it results in a decline that would warrant listing it in a threatened category. Further study is required, however, to assess the effects of hunting. Allen’s Swamp Monkeys are found in relatively high densities in Salonga National Park and Tumba-Lediima Reserve, DR Congo, and are marginally present in Nouabalé-Ndoki National Park in the Republic of the Congo. It is a little-known species that is very difficult to observe and follow in the wild, and further information on its distribution and conservation status is needed.

Bibliography. Colyn (1988), Colyn, Gautier-Hion & Verheyen (1991), Disotell & Raaum (2002), Gautier-Hion (1988), Gautier-Hion et al. (1999), Gautier (1985), Gebo & Sargis (1994), Gevaerts (1992), Groves (2000b, 2001), Hill (1966), Kingdon (1997), Maisels, Blake et al. (2006), McGraw (1994), Oates & Groves (2008a), Tosi, Buzzard et al. (2002), Zeeve (1991).

Figures

39. Yellow Baboon (Papio cynocephalus), 40. Kinda Baboon (Papio kindae), 41. Chacma Baboon (Papio ursinus), 42. Olive Baboon (Papio anubus), 43. Guinea Baboon (Papio papio), 44. Hamadryas Baboon (Papio hamadryas), 45. Gelada (Theropithecus gelada)

Distribution. NW DR Congo and NE Republic of the Congo, in lowland forests of the Congo Basin on both sides of the lower and middle Congo (c.16” E to 26°-27° E); S of the Congo Riverits distribution extends E to the Lomami River system (c.3° N to 6° 30° S); it has also been recorded on twoislands in the Sangha River. Its presence in NE Angola requires confirmation.