Piliocolobus gordonorum, Matschie, 1900

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 : 707

91.

Udzungwa Red Colobus

Piliocolobus gordonorum

French: Colobe des Gordon / German: Uzungwe-Stummelaffe / Spanish: Colobo rojo de Udzungwa

Other common names: Iringa Red Colobus, Uhehe Red Colobus

Taxonomy. Piliocolobus gordonorum Matschie, 1900 ,

Tanzania, Uzungwa (= Udzungwa) Mountains, Uhehe.

Modern taxonomic arrangements of the colobus monkeys either divide the red colobus and the Olive Colobus into two genera, Piliocolobus and Procolobus , respectively, or consider them to belong to one genus, Procolobus , with two subgenera ( Procolobus for the Olive Colobus and Piliocolobus for the red colobus). We follow here C. P. Groves in his publications of 2001 and 2007 in using two genera. There is a rare red-backed morph (representing c¢.2% of the population), in which the upper bodyis black with a brick-red lumbar region and rump. Monotypic.

Distribution. SW Tanzania, known only from the Udzungwa Mts, a few small tracts of forest between the Little Ruaha and Ulanga rivers (S of Iringa), and several forest patches of the Kilombero Valley at the E base of the Udzungwa Mts (Magombera, Kiwanga, Kalunga, and in gallery forest along the Msolwa River S of the railway to its confluence with the Kilombero River, including the Ibiki and Msitu ya Kinjugu forests).

Descriptive notes. Head-body 60-66 cm (females), tail 64-69 cm (females); no measurements for males or body weight data for either sex are available. The Udzungwa Red Colobus is somewhat larger, but with a shorter tail, than the Ashy Red Colobus ( P. tephrosceles ). It is a deep shining black above (rarely with a red lumbar region and rump), with white on underside and inner surfaces of limbs. Arms and thighs are black, but shanks are mixed with silvery. Lower legs black mixed with silvery. Tail is short and slightly bushy, being black or mixed with ocherous above and tending to be off-white below. Crown is a shiny red, with laterally directed hairs forming a sort of toupee. Face lacks pigmentation around the nose and mouth, and cheeks are white and separated from red of the crown by a thick black line along the temples. A “panache” (a tuft of hair) is present but weakly developed. Skull is broad, short-faced, and small-toothed. A mtDNA analysis shows that the Udzungwa Red Colobus is most closely related to the Zanzibar Red Colobus ( P. kirkii ), but distinct.

Habitat. A variety of forest habitats, including lowland old growth,riparian, groundwater, secondary, and montane forests of the Udzungwa Mountains and Miombo (Brachystegia, Fabaceae ) woodland adjacent to old growth or secondary forest in the lower parts of the Mwanihana Forest in the Udzungwa Mountains National Park and elsewhere. Systematic population surveys examining the relative abundance of primates in the Mwanihana Forest found that the Udzungwa Red Colobus preferred moderate to old growth semi-deciduous forest, but it was also found nearly as often in evergreen forest. It was recorded in deciduous forest and open areas (logged, regenerating forest with shrubs and scattered trees) but in lower numbers. The Udzungwa Red Colobus occurs at elevations of 200-2200 m, althoughit is less abundant at the higher elevations.

Food and Feeding. Diet of the Udzungwa Red Colobus includes young leaves and mature leaves, fruits, flowers, buds, and possibly seeds.

Breeding. Female Udzungwa Red Colobus display a substantial pink sexual swelling during the periovulatory period (larger than in the Ashy Red Colobus ).

Activity patterns. There is no specific information available for this species.

Movements, Home range and Social organization. The movements and home range of the Udzungwa Red Colobus are unknown, but group size is highly variable at 3-83 individuals. Groups are smaller in forests that are small (less than 5 km?), dominated by deciduous trees, or heavily degraded by human activities than are groups living in large, intact, and relatively mature blocks of moist, mixed evergreen and semi-deciduous forest. Groups typically have multiple adult males and females, and variation in numbers of adult males accounts for much of the variability in group size.

Status and Conservation. CITES Appendix II. Classified as Endangered on The IUCN Red Last (as Procolobus gordonorum ). The Udzungwa Red Colobusis listed as Class B in the African Convention on the Conservation of Nature and Natural Resources. It has an extent of occurrence of less than 5000 km®, populations are highly fragmented with no or limited movement between forest fragments, and there is a continuing decline in the distributional extent of occurrence and area of occupancy due to logging, conversion to agriculture, collection of firewood, and charcoal production. The Udzungwa Red Colobus is sometimes hunted for its meat, particularly in the western and south-western parts of the range. Total population size is unknown and difficult to determine, but clearly in the thousands. At least one published estimate puts it at 15,400 individuals, but this might be too high. An earlier estimate by W. Rodgers and K. Homewood in 1982 was 10,000 individuals, but they emphasized that the largest single interbreeding population was certainly less than 2000. In the Udzungwa Mountains, the Udzungwa Red Colobus was the most frequently seen primate, with an average of 0-59 groups/km walked. It occurs in ten protected areas in Tanzania: Udzungwa Mountains National Park; Kiranzi-Kitungulu, Magombero, Mangula, Matundu, New Dabaga/Ulangambi, Nyanganje, Udzungwa Scarp, and West Kilombero forest reserves; and Selous Game Reserve. It is relatively secure in Udzungwa Mountains National Park, but only about half ofits range is protected in this area. Its remaining habitat is either on public land or in forest reserves (including New Dabaga/Ulangambi Forest Reserve) and is not effectively protected. Magombero Forest Reserve, for example, still needs to be legally incorporated into Selous Game Reserve, which the government of Tanzania had promised to do in 1980. In 2004, T. Struhsaker and colleagues highlighted the following conservation priorities for the Udzungwa Red Colobus : 1) annexation of a number of forest reserves to the Udzungwa Mountains National Park (West Kilombero, Udzungwa Scarp, Matundu, and Nyanganje); 2) annexation of a number of forests to Selous Game Reserve (Magombera, Ibiki, and all other forest remnants along the Msolwa River); 3) prevention of fire to allow forest regeneration and expansion and creation of corridors between forest blocks; and 4) more effective law enforcement to prevent fires, illegal logging, and poaching.

Bibliography. Decker (1994a, 1996), Groves (2001, 2007b), Grubb et al. (2003), Marshall et al. (2005), Rodgers (1981), Rovero et al. (2006), Struhsaker & Leland (1980), Struhsaker et al. (2004).

Figures

Distribution. SW Tanzania, known only from the Udzungwa Mts, a few small tracts of forest between the Little Ruaha and Ulanga rivers (S of Iringa), and several forest patches of the Kilombero Valley at the E base of the Udzungwa Mts (Magombera, Kiwanga, Kalunga, and in gallery forest along the Msolwa River S of the railway to its confluence with the Kilombero River, including the Ibiki and Msitu ya Kinjugu forests).