Ruwenzorisorex suncoides (Osgood, 1936)

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 : 466

204.

Rwenzori Shrew

Ruwenzorisorex suncoides

French: Pachyure du Rwenzori / German: Ruwenzori-Spitzmaus / Spanish: Musarana de Rwenzori

Taxonomy. Sylvisorex suncoides Osgood, 1936 ,

“ Kalongi , western slope of Mount Ruwenzori, Belgain Congo [= DR Congo]. Alt. 7,000 ft. [= 2134 m].”

Ruwenzorisorex seems to be close to Sun- cus or possibly Sylvisorex based on genetic data. R. suncoides was originally described as a species of Sylvisorex and was moved to Ruwenzorisorex due to brain morphology and its very distinctive morphology, which is supported now by genetic data. Mono-

typic.

Distribution. Endemic to the Albertine Rift in E DR Congo, SW Uganda, Rwanda, and Burundi.

Descriptive notes. Head-body 84-102 mm, tail 55-70 mm, ear 7-8 mm, hindfoot 16-19 mm; weight 18-23 g. The Rwenzori Shrew is large (larger than any Sylvisorex ) and semi-aquatic (the only semi-aquatic Crocidurinae ), with woolly, waterrepellent fur. Dorsum is blackish gray, flecked with paler gray; individual hairs have slate-gray bases and brown tips; and there are long pale guard hairs on rump. Venter is slate-gray, with hairs with gray bases and pale gray or brownish tips. Vibrissae are well developed, muzzle is swollen, eyes are very small, and ears are small and do not extend past fur. Feet are like those of terrestrial species, with short claws. Tail is c.40% of head-body length, slightly bicolored (dark above and paler below), and lacking long bristle hairs. Skull is elongated and dorsoventrally compressed, with concave profile in lateral view. There are four unicuspids, and fourth is only a little smaller than third. Lower incisors are smooth and without denticulations. Unlike all other crocidurines, the Rwenzori Shrew shares similarities with aquatic shrews in Nectogalini, including their enlarged medulla oblongata, enlarged foramen magnum, and expanded trigeminal nerve system in muzzle, but they do not have altered tails or feet as in other aquatic species. Dental formulais 13/1, C1/1, P2/1,M 3/3(x2)=30.

Habitat. Near clear shallow streams in primary montane moist forests at elevations of 1800-2350 m. Ugandan records of the Rwenzori Shrew come from meandering streams going through Brillantaisia (Acanthaceae) swamps, and Burundi records come from streams surrounded by forests of scattered Syzygium (Myrtaceae) , Symphonia (Clusiaceae) , Arundinaria bamboo, Cyathea tree ferns, and Tabernaemontana (Apocynaceae) .

Food and Feeding. Rwenzori Shrews have been attracted to animal baits of fish and worms.

Breeding. No information.

Activity patterns. The Rwenzori Shrew is the only semi-aquatic shrew in Africa.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Vulnerable on The IUCN Red List. The Rwenzori Shrew has a very restricted distribution (area of occupancy is almost certainly less than 2000 km?) and is rare (only known from ten specimens). It is found in multiple nature reserves, including Rwenzori Mountains National Park and Bwindi-Impenetrable Forest National Park in Uganda and Bururi Nature Reserve and Kibira National Park in Burundi. Its biggest threats seem to be coal mining, logging operations, and conversion of natural habitat for agricultural purposes.

Bibliography. Hutterer (1986a), Kerbis Peterhans (2013b, 2016), Meegaskumbura et al. (2014), Quérouil et al. (2001).

Figures

182. Palawan Moss Shrew (Palawanosorex muscorum), 183. Pearson’s Long-clawed Shrew (Solisorex pearsoni), 184. Kelaart’s Long-clawed Shrew (Feroculus feroculus), 185. Etruscan Shrew (Suncus etruscus), 186. Sri Lankan Shrew (Suncus fellowesgordoni), 187. Malayan Pygmy Shrew (Suncus malayanus), 188. Bornean Pygmy Shrew (Suncus hosei), 189. Jungle Shrew (Suncus zeylanicus), 190. Asian House Shrew (Suncus murinus), 191. Sr 1 Lankan Highland Shrew (Suncus montanus), 192. Nilgir 1 Highland Shrew (Suncus niger), 193. Anderson’s Shrew (Suncus stoliczkanus), 194. Day’s Shrew (Suncus dayi), 195. Flores Shrew (Suncus mertensi), 196. Black Shrew (Suncus ater), 197. Taita Shrew (Suncus aequatorius), 198. Greater Dwarf Shrew (Suncus lixa), 199. Hutu-Tutsi Dwarf Shrew (Suncus hututsi), 200. Least Dwarf Shrew (Suncus infinitestmus), 201. Remy’s Pygmy Shrew (Suncus remyi), 202. Lesser Dwarf Shrew (Suncus varilla), 203. Climbing Shrew (Suncus megalurus), 204. Rwenzori Shrew (Ruwenzorisorex suncoides), 205. Johnston's Forest Shrew (Sylvisorex johnstoni), 206. Akaibe’s Forest Shrew (Sylvisorex akaiber), 207. Moon Forest Shrew (Sylvisorex lunaris), 208. Greater Forest Shrew (Sylvisorex ollula), 209. Lesser Forest Shrew (Sylvisorex oriundus), 210. Bioko Forest Shrew (Sylvisorex isabellae), 211. Corbet’s Forest Shrew (Sylvisorex corbeti), 212. Bamenda Forest Shrew (Sylvisorex silvanorum), 213. Rainforest Shrew (Sylvisorex pluvialis), 214. Cameroonian Forest Shrew (Sylvisorex camerunensis), 215. Mount Cameroon Forest Shrew (Sylvisorex moro), 216. Kongana Forest Shrew (Sylvisorex konganensis), 217. Volcano Forest Shrew (Sylvisorex vulcanorum), 218. Grant's Forest Shrew (Sylvisorex granti), 219. Howell's Forest Shrew (Sylvisorex howelli), 220. Armored Hero Shrew (Scutisorex somereni), 221. Thor’s Hero Shrew (Scutisorex thor), 222. Greater Large-headed Shrew (Paracrocidura maxima), 223. Lesser Large-headed Shrew (Paracrocidura schoutedeni), 224. Grauer’s Large-headed Shrew (Paracrocidura graven), 225. Piebald Shrew (Diplomesodon pulchellus)

Distribution. Endemic to the Albertine Rift in E DR Congo, SW Uganda, Rwanda, and Burundi.