Cephalophus arrhenii (Lönnberg, 1917)

Don E. Wilson & Russell A. Mittermeier, 2011, Bovidae, Handbook of the Mammals of the World – Volume 2 Hoofed Mammals, Barcelona: Lynx Edicions, pp. 444-779 : 728-729

260.

Uele White-bellied Duiker

Cephalophus arrhenii

French: Céphalophe d'Arrhenius / German: Uélle-WeiRbauchducker / Spanish: Duiker de vientre blanco del Uele

Other common names: Eastern White-bellied Duiker

Taxonomy. Cephalophus castaneus arrhenii Lonnberg, 1917 ,

Beni, Semliki Valley, Zaire.

Although initially described as a subspecies of C. castaneus , C. arrhenu 1s most closely related to C. leucogaster , of which it was formerly considered a subspecies. Monotypic.

Distribution. S Central African Republic and DR Congo NE of the Congo River.

Descriptive notes. Head—body 105 cm,tail 10-5 cm (from a single male from Ituri Forest, DR Congo), shoulder height c.42-51 cm; weight 14.7-21 kg. Females weigh approximately 11% more than males (averaging 18-9 kg vs. 16-8 kg, respectively). The Uele White-bellied Duikeris slightly larger than the Western White-bellied Duiker (C. leucogaster ). Overall color is sandy brown, tending to be both paler and browner than its western sister species. The belly is white, blending gradually with the color of the flanks; the throat and rear surfaces of the rump are also whitish in color. The shoulders and front limbs are grayish, and the hocks of the hindlimbs are marked with black. As in the Western White-bellied Duiker, a black dorsal stripe is present from the shoulders (or occasionally from the back of the head) to the base of the tail; it is narrow at the ends and widest in the middle of the back. The dorsal stripe is broader than that of the Western White-bellied Duiker; the minimum width at its widest point is 6-7 cm and the average width is 10-9 cm. The edges tend to be diffuse, sometimes appearing scalloped. The dorsal stripe may continue as a thin line to the tip of the otherwise sandy-colored tail. There is a pronounced tuft of black and white hairs at the tail tip. The face is generally reddish, with a dark blaze along the bridge of the nose that expands over the forehead. The coronal tuft is reddish. Horns are present in both sexes; they are short and pointed, with heavily ridged bases. In males, they measure 2.1-6. 9 cm in length; those of females are shorter, 1-:8.2-9 cm. Dental formulais10/3, C0/1,P 3/3, M 3/3 (x2) = 32.

Habitat. L.owland primary forest with an open understory. The Uele White-bellied Duiker tends to avoid dense thickets. Population densities are c.6 ind/km® in open forests dominated by Gilbertiodendron dewevrei (higher than other sympatric duiker species). In mature mixed forest, density decreases to 4-5 ind/km?, likely due to competition with other duikers.

Food and Feeding. Highly frugivorous, with fruits and seeds comprising 80-100% of examined stomach contents throughout most of the year. Seasonally dominant dietary items include seeds of Landolphia spp., Donella pruniformis, and the unripe (still soft) fruits of Klainedoxa gabonensis and Irvingia grandifolia. In captive feeding trials in the Ituri Forest, DR Congo, the fruits of Ficus exasperata, Maesopis schweinfurthu, Blighia welwitschii, Cleistanthus michelsonii, Klainedoxa gabonensis, and the opening flower buds of Gulbertiodendron dewevret were preferred. Fruits from Aidia micrantha and Musanga cecropioides were also consumed, but those from Dacryodes yangambiensis were never eaten. Fallen flowers and fungi are principal dietary components when fruit availability is low. The Uele White-bellied Duiker ranges widely searching for fruiting trees. This species will actively seek out groups of primates to feed on dropped material; individuals have also been documented selectively foraging through primate feces for edible seeds.

Breeding. Breeding likely occurs throughout the year, although a peak in births has been noted in August-November (the rainy season). Litter size is one. Two full-term fetuses weighed 1-3 kg and 1-5 kg.

Activity patterns. Diurnal, butlittle other specific information available forthis species.

Movements, Home range and Social organization. Group size of the Uele White-bellied Duiker is one or two individuals: pairs are generally a juvenile traveling with its mother. Both sexes disperse from the home range of their mother upon reaching sexual maturity. Home ranges of males and females overlap, and average 0-63 km? in mixed forest and 0-58 km?® in Gilbertiodendron forests.

Status and Conservation. Classified as Least Concern on The IUCN Red List (under C. leucogaster ). The large home ranges of Uele White-bellied Duikers may increase the risk associated with snareand net-hunting when compared to more sedentary species; it is one ofthe first duiker species to be locally eliminated when high-intensity hunting occurs.

Bibliography. Blancou (1935), Grubb & Groves (2001), Hart (In Press), Heymans & Lejoly (1981), Karesh etal. (1995), IUCN/SSC Antelope Specialist Group (2008b), Kingdon (1997), Molloy & Hart (2002), Roberts (1996), Skinner & Chimimba (2005).

Figures

On following pages: 259. Western White-bellied Duiker (Cephalophus leucogaster); 260. Uele White-bellied Duiker (Cephalophus arrhenii); 261. Red-flanked Duiker (Cephalophus rufilatus); 262. Natal Red Duiker (Cephalophus natalensis); 263. Harvey's Duiker (Cephalophus harveyi); 264. Black-fronted Duiker (Cephalophus nigrifrons); 265. ltombwe Duiker (Cephalophus hypoxanthus); 266. Rwenzori Duiker (Cephalophus rubidus); 267. Mount Elgon Duiker (Cephalophus fosteri); 268. Mount Kenya Duiker (Cephalophus hooki)

Distribution. S Central African Republic and DR Congo NE of the Congo River.