14.

Wilson's Spiny Mouse

Acomys wilsoni

French: Acomys de Wilson / German: Wilson-Stachelmaus / Spanish: Raton espinoso de Wilson

Taxonomy. Acomys wilson: Thomas, 1892,

Mombasa, Kenya.

Acomys wilsoni was formerly included in the A. subspinosus species group, and then genetic and molecular analyses found it to be a valid species, closely related to A. percivali . R. Matthey in 1968 found a chromosomal complement of 2n = 60 and FN = 76, and C. Fadda and colleagues in 2001 and M. Corti and colleagues in 2005 found 2n = 62 and FN = 76. The most recent molecular phylogeny revealed high diversity in Tanzania, and W. N. Verheyen and colleagues in 2011 found that A. wilson: is probably a species complex based upon mtDNA sequences (cytochrome-b). Five subspecies recognized.

Subspecies and Distribution.

A. A.w.wilsoniThomas,1892—knownonlyfromthetypelocalityincoastalS Kenya. A. A.w.ablutusDollman,1911—NyamaNyango,NEwaso Ng’iroRiver,Kenya.

A. A.w.argillaceusHinton&Kershaw,1920—SSouthSudan.

A. A.w.enidSt.Leger,1932—NUganda. A. A.w. nubilus Dollman, 1914 — known only from the type locality in SW Kenya.

A.w. present in S Ethiopia, S Somalia, and N Tanzania, but subspecies involved not known.

Descriptive notes. Head—body 89-114 mm, tail 65-100 mm, ear 14-16 mm, hindfoot 14-16 mm; weight 22-47 g. Wilson's Spiny Mouse is very small, with short and broad feet, orange-rufous pelage with black dominant on head and nape, and belly white. Tail is slender and ¢.94% of head-body length.

Habitat. Riverine areas with trees and plateaus of the Omo River in southern Ethiopia; “kopjes” (isolated rock ridges) shared with Percival’s Spiny Mouse ( A. percivali) in central Kenya; and dense shrubby vegetation and sometimes houses in Kenya.

Food and Feeding. Wilson's Spiny Mouse is omnivorous; diets are dominated by insects and vary seasonally. In dry seasons, arthropods represent 60-95% of diets, followed by seeds (5—40%) and stems and leaves. During wetter seasons, vegetation in diets increases slightly and arthropods decrease.

Breeding. Pregnant Wilson’s Spiny Mice have been reported throughout the year. Each female canhave 7-9 litters/year and produce an average of 17-4 young/year. Gestation lasts 4-6 weeks, and litter size averages two young. Numbers of embryos are 1-4/female. Young are precocious at birth, weigh 3-4 g, and reach adult size at 17 g.

Activity patterns. Wilson's Spiny Mouse is nocturnal and an excellent climber; it might be arboreal to scansorial.

Movements, Home range and Social organization. In captivity, Wilson’s Spiny Mice are not aggressive, even at high density. Adults have widely overlapping home ranges.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Wilson's Spiny Mouse is found in protected areas, and there are no major threats reported.

Bibliography. Corti et al. (2005), Delany (1964), Fadda et al. (2001), Hubert (1978b), Matthey (1968), Neal (1983, 1984), Takata (2013), Verheyen et al. (2011).