Sylvisorex isabellae (Heim de Balsac, 1968)

Russell A. Mittermeier & Don E. Wilson, 2018, Soricidae, Handbook of the Mammals of the World – Volume 8 Insectivores, Sloths and Colugos, Barcelona: Lynx Edicions, pp. 332-551 : 468

publication ID 10.5281/zenodo.6870843


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scientific name

Sylvisorex isabellae


210. View Plate 19: Soricidae

Bioko Forest Shrew

Sylvisorex isabellae View in CoL

French: Pachyure de Santa Isabel / German: Bioko-Waldmoschusspitzmaus / Spanish: Musarana de bosque de Bioko

Other common names: Isabella Forest Shrew, Isabella Shrew

Taxonomy. Sylvisorex morio isabellae Heim de Balsac, 1968 View in CoL , Pic Santa Isabel , Refugium , 2000 m, Fernando Po (= Bioko Island) , Equatorial Guinea.

There is a population in the Bamenda Highlands of south-western Cameroon that has been attributed to S. isabellae , although it might represent a distinct cryptic species. Monotypic.

Distribution. N Bioko I and SW Cameroon. View Figure

Descriptive notes. Head-body 54-63 mm, tail 54-59 mm, ear 8-9 mm, hindfoot 10-13 mm; weight 5-5-9 g. The Bioko Forest Shrew is small, with soft and dense pelage. Dorsum is dark reddish brown, and venter is generally slightly paler reddish brown, depending on the angle. Feet are brown, with inconspicuous dark brown scales and sparse short dark brown hairs. Tail is 90% of headbody length, blackish brown, and slightly lighter below. Braincase is high-domed, first incisors are long and hooked,first unicuspid is large while second to fourth are smaller and subequal, and third molar is medium in size. There are four unicuspids. Chromosomal complement has 2n = 36 and FN = 50 for the Cameroonian population.

Habitat. Montane tropical moist forests and grasslands found above the tree line at elevations of 2000-2400 m.

Food and Feeding. No information.

Breeding. No information.

Activity patterns. No information.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Endangered on The IUCN Red List. The Bioko Forest Shrew has a very small extent of occurrence (less than 5000 km?), all individuals are in fewer than five locations, and there is continuing decline in extent and quality ofits habitat. The Bioko Forest Shrew is threatened by habitat loss mainly from logging operations and conversion of land to agricultural uses. Although it is present in Mount Oku Faunal Reserve in the Bamenda Highlands of Cameroon (although its taxonomyis uncertain), there are no conservation plans in place for the Bioko Forest Shrew, and there is urgent need to conserve suitable montane forest habitat, particularly on Bioko Island.

Bibliography. Heim de Balsac & Meester (1977), Hutterer (2013ah), Hutterer & Howell (2008e), Schlitter et al. (1999).














Sylvisorex isabellae

Russell A. Mittermeier & Don E. Wilson 2018

Sylvisorex morio isabellae

Heim de Balsac 1968
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