200.

Least Dwarf Shrew

Suncus infinitestmus

French: Pachyure de Heller / German: Zwergwimperspitzmaus / Spanish: Musarana enana minima

Taxonomy. Pachyura infinitesima Heller, 1912,

Rumruti, 7000 ft. (= 2135 m), Laikipia Plateau, Kenya.

The seven species of endemically African Suncus seem to be more closely related to Sylvisorex than to other species of Suncus. They might be better placed in Sylvisorex but are retained in Suncus here until additional research is conducted. Suncus infinitesimus possibly represents a species complex considering its wide and frag-

mented distribution that consists of three widely separate clusters. It might be closest genetically to S. remy, which together might be close to S. etruscus or S. varilla, although phylogeny in Suncus is obscure and uncertain. Three names that have been allocated to the three distributional clusters of S. infinitesimus might be valid but require additional research: chriseos in South Africa, infinitesimus in East Africa, and ubanguiensis in Central Africa. Monotypic.

Distribution. Found in three main clusters in C Cameroon and SW Central African Republic (both are known only from single records), W Kenya, and S & E South Africa and Swaziland; range is probably much more extensive, although it has not been collected readily outside its South African and Kenyan distribution.

Descriptive notes. Head-body 42-62 mm, tail 23-31 mm, ear 3-7 mm, hindfoot 7-9 mm; weight 2-8-3-1 g. The Least Dwarf Shrew is one of the smallest species of shrew. Dorsum is darkish gray brown (hairs dark slate-gray at bases, with white subterminal bands and brown tips), with gray venter (hairs on venter dark slate-gray at bases with white tips); and dorsum and venter fade together on sides. Muzzle is long and narrow, head is slender, eyes are small, and ears large and round. Feet are grayish brown. Tail is ¢.55% of head-body length and bicolored, being brown above and paler below. Skull is shorter than in the Climbing Shrew (S. megalurus). Female Least Dwarf Shrews have three inguinal mammae. There are four unicuspids, and fourth is very small; teeth are unpigmented white.

Habitat. Forested and open habitats, including montane grasslands, savannas, mixed bushveld, and primary moist forests at elevations of 1700-2100 m. Least Dwarf Shrews have often been found associated with mounds of the snouted termite (Trinervitermes trinervoides).

Food and Feeding. Least Dwarf Shrews are presumably insectivorous and are known to eat beetles in captivity.

Breeding. Breeding of Least Dwarf Shrews involves nose-to-tail chasing, followed by brief copulation.

Activity patterns. No information.

Movements, Home range and Social organization. Least Dwarf Shrews are usually solitary. They shelter in termite mounds that are moist and cool compared with warmer temperatures outside, which reduces metabolic costs of regulating body temperature in warm environments. Least Dwarf Shrews build ball-shaped nests in termite mounds, and they might go into torpor similarly to other species of crocidurines.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Least Dwarf Shrew does not seem to have any major direct threats, although it is considerably rare to catch throughoutits wide but fragmented distribution.

Bibliography. Baxter & Dippenaar (2013h), Cassola (2017b), Dubey, Salamin, Ohdachi et al. (2007), Dubey, Salamin, Ruedi et al. (2008), Heim de Balsac & Meester (1977), Lynch (1983), Meester & Lambrechts (1971), Quérouil et al. (2001), Ray & Hutterer (1996), Young & Evans (1993).