Philantomba aequatorialis (Matschie, 1892)

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 : 714

235.

Eastern Blue Duiker

Philantomba aequatorialis

French: Céphalophe équatorial / German: Ostafrika-Blauducker / Spanish: Duiker azul oriental

Other common names: Equatorial Blue Duiker, Zanzibar Blue Duiker

Taxonomy. Cephalophus aequatorialis Matschie, 1892 ,

Chagwi, Uganda.

Formerly considered to be a grouping of subspecies under P. monticola . Individuals from Pemba Island ( Tanzania, adjacent to Zanzibar) are sometimes listed as a separate subspecies (pembae), but they are not presently considered distinct. Three subspecies are recognized.

Subspecies and Distribution.

P.a.aequatorialisMatschie,1892—fromCCentralAfricanRepublicandEDRCongo(EfromLisala,StoUpemba)toSWSudanandWUganda,withanisolatedpopulationinSSudan(ImatongMts).RangeborderedtotheSandWbytheCongoRiver.

P.a.musculoidesHeller,1913—EUganda,WKenya(EtotheRiftValley),andNWTanzania.

P. a. sundevalli Fitzinger, 1869 — Zanzibar, Pemba, and Mafia Is ( Tanzania), coastal mainland Kenya and Tanzania.

Descriptive notes. Head-body c. 60 cm, tail 6.5-9 cm, shoulder height 31-38 cm; weight 4-3 kg (3.9-5 kg) for males and 5-4 kg (4-2-6-5) for females from Zanzibar. Head—body 60-67 cm, tail 8-12 cm, ear 4:7.5-6 cm, for animals of both sexes from Uganda. Few specific body measurements are available for the Eastern Blue Duiker; skull measurements indicate that females are usually slightly larger than males. Overall color is a drab brown; the subspecies sundevalli tends to be paler than the other two subspecies. The dorsal surface tends to be darker in color than the flanks. A restricted black or very dark brown patch is present on the upper haunches on eitherside of the tail base; the transition between the dark croup and paler haunchesis relatively sharp, although less so than in the Western Blue Duiker (P. congica) and the Bioko Blue Duiker (P. melanorhea). The underparts range from pale gray (subspecies aequatorialis and musculoides) to whitish (sundevalli). Horns are always present in males, tending to be rather long: approximately 4-3 cm for male sundevalli and 3-17 cm for male musculoides. There is significant variation among males of subspecies aequatorialis, with a tendency for shorter horns in eastern parts of the subspecies’ range; average regional horn length varies between 2: 2 cm and 4 cm, although an isolated specimen from south-western Sudan had horns 4-6 cm long. Presence of horns in femalesis highly variable. Female musculoides appear never to grow horns, and they are regularly absent from female aequatorialis (especially in Uganda). However, when present in aequatorialis and sundevalli, female horns are fully developed and relatively long; one record from Pemba is 3-4 cm. Horn length from aequatorialis females is 2.5-3. 3 cm; as in the males, a single specimen from Sudan had very long horns: 4-05 cm. Dental formulais 10/3, C0/1,P 3/3, M 3/3 (x2) = 32.

Habitat. The Eastern Blue Duiker inhabits a wide range of forested habitats, including lowland rainforest, montane forest, and dry thickets. The species has been recorded from sea level ( Zanzibar) to 3000 m (the Rwenzori Mountains in Uganda and Mount Kenya in Kenya). In the Ituri Forest, DR Congo, subspecies aequatorialis densities average 24-2 ind/km?, with a range in estimates from 15 ind/km? to 69 ind/km?The subspecies musculoides in Uganda lives at densities of 5-13 ind/km?. On Zanzibar, population densities of sundevalli are highest in undisturbed high thicket, averaging 34-1 ind/km?. The lowest densities on Zanzibar are in intermediate secondary thicket (14-6 ind/km?); young secondary thickets appear to be avoided.

Food and Feeding. Frugivorous/folivorous. Seeds or fruits from plants such as Maesopsis, Ricinodendron, Cordia, Musanga, and Pycnanthus have been recorded in the diet in Uganda; commonly consumed leaves in this region include Milbraediodendron and Mammea africanum, as well as Isoglossa, Brachylaena, and Urtica. Captive feeding trials in the Ituri Forest, DR Congo, indicated a strong preference for the fruits of Ficus exasperata; those of Aidia micrantha, Maeposis schweinfurthii, Cleisthanthus michelsonii, Klainedoxa gabonensis, and the opening flower buds of Gilbertiodendron dewevreiwere also consumed at high levels. The Eastern Blue Duiker is known to forage in agricultural areas, feeding on crops such as sweet potato (/pomea sp.).

Breeding. There islittle specific information available forthis species, but likely breeds year-round; adult females with late-term fetuses were observed in Zanzibar bushmeat markets in every month studied (July-December). There are several birth records in January-February from Uganda and western Kenya.

Activity patterns. Diurnal; generally most active around dawn and dusk. Foraging patterns show short periods of activity interspersed with periods of rest and rumination.

Movements, Home range and Social organization. Group size is typically two or three animals, most likely an adult pair and their subadult offspring. Distinct home ranges are defended against other members of the same species; territorial behavior is believed to be mostly the responsibility of the male. Each home range is covered with a network of regularly used pathways.

Status and Conservation. CITES Appendix II (under P. monticola ). Classified as Least Concern on The IUCN Red List (combined with the other nine blue duiker species within the P. monticola complex). The widespread distribution of the Eastern Blue Duiker includes large tracts of undisturbed forest in central DR Congo, and it is the most common antelope species in several areas (including the Ituri Forest). Intense hunting pressure has led to localized declines in the coastal forests of Tanzania and in the forests of western Kenya.

Bibliography. Andanje et al. (2011), East (1999), IUCN/SSC Antelope Specialist Group (2008as), Karesh et al. (1995), Kingdon (1982), Molloy & Hart (2002), Williams et al. (1996), Wilson (2001).

Figures

233. Western Blue Duiker (Philantomba congica), 234. Bioko Blue Duiker (Philantomba melanorhea), 235. Eastern Blue Duiker (Philantomba aequatorialis), 236. Mountain Blue Duiker (Philantomba lugens), 237. Simpson’s Blue Duiker (Philantomba simpsoni), 238. Malawi Blue Duiker (Philantomba hecki), 239. Zimbabwe Blue Duiker (Philantomba bicolor), 240. Cape Blue Duiker (Philantomba monticola), 241. Angolan Blue Duiker (Philantomba anchietae), 242. Zambian Blue Duiker (Philantomba defries)

Subspecies and Distribution. P.a.aequatorialisMatschie,1892—fromCCentralAfricanRepublicandEDRCongo(EfromLisala,StoUpemba)toSWSudanandWUganda,withanisolatedpopulationinSSudan(ImatongMts).RangeborderedtotheSandWbytheCongoRiver. P.a.musculoidesHeller,1913—EUganda,WKenya(EtotheRiftValley),andNWTanzania. P. a. sundevalli Fitzinger, 1869 — Zanzibar , Pemba, and Mafia Is ( Tanzania ), coastal mainland Kenya and Tanzania .