Micropotamogale lamotte, Heim de Balsac, 1954

Russell A. Mittermeier & Don E. Wilson, 2018, Potamogalidae, Handbook of the Mammals of the World – Volume 8 Insectivores, Sloths and Colugos, Barcelona: Lynx Edicions, pp. 174-179 : 178

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Nimba Otter-shrew

Micropotamogale lamotte

French: Micropotamogale du Nimba / German: Nimba-Otterspitzmaus / Spanish: Musarana nutria de Nimba

Other common names: Pygmy Ottershrew

Taxonomy. Micropotamogale lamotter Heim de Balsac, 1954 ,

“Ziéla, dans une savane au pied du Nimba [= savanna at the foot of Mt. Nimbal], altitude 550 m,” Guinea . This species is monotypic.

Distribution. Endemic to the Upper Guinea rainforest zone with its distribution centered on Mt Nimba (SE Guinea, N & E Liberia, and E Ivory Coast).

Descriptive notes. Head-body 120-155 mm, tail 95-134 mm, ear 9-11 mm,

hindfoot 19-21 mm; weight 32-95 g. The Nimba Otter-shrewis small and rat-sized and superficially resembles a large shrew. Fur is soft, rather shaggy, and grayish brown to black dorsally, with paler bases to individual hairs. Dorsal pelage is sprinkled with long pale-tippedhair, giving it a slightly grizzled appearance when dry. Ventral pelage is similar to dorsal pelage, but hairs are slightly paler, only noticeable when pelage is dry. When wet, the Nimba Otter-shrew looks uniformly dark brown or black. Headis relatively large, with broad muzzle covered with long vibrissae; eyes are small. Ears are typically shrew-like and relatively small. Tail is thick, similar to head-bodylength and sparsely covered with long hair along its entire length. Limbs are short and similar in color to dorsum, with five digits on forefeet and hindfeet. Second and third digits of hindfeet are fused to form comb used for grooming. No webbing occurs between digits on forefeet or hindfeet.

Habitat. Small streams and wetlands in rainforest, typically in upland, hilly areas above elevations of 400 m but sometimes as low as 200 m. Most records of Nimba Ottershrews are from forested streams, but they have occasionally been captured in rice fields adjacent to blocks offorest. Clear water appears to be an important habitat requirement because Nimba Otter-shrews seem to disappearfrom streams after mining activity has increased turbidity of water. Thick vegetation along banks ofstreams also appears to be an important habitat requirement.

Food and Feeding. The Nimba Otter-shrew mostly eats crabs, which are capturedin the water but consumed on land. Crabs are attacked from the rear presumably to prevent injury frompincers, andskeletonis crushed atjunction ofcephalothorax and abdomen.

Fish and insects are also eaten, but crabs are preferred over other aquatic prey. Tadpoles and small mammals are not eaten. Daily consumption in captivity was c.40 g offish.

Breeding. A pregnant female Nimba Otter-shrew was recorded during the dry season in December. Averagelittersize is 2-6 young. Gestation is morethan 50 days. Young are born naked. Eyes open after 23 days, and solid food is eaten after 40 days.

Activity patterns. Nimba Otter-shrews are nocturnal and mostly aquatic. Foraging activities begin after sunset, and individuals return to burrows before sunrise. Despite lack offlattenedtail and webbedfeet, Nimba Otter-shrews are strong swimmers.

Movements, Home range and Social organization. The Nimba Otter-shrewis almost entirely aquatic in its foraging activities. Radio-taggedindividuals traveled 300 m or more upstream and downstreamofsite of capture. Movement is confinedto streams, with almost no movement away from water. It appears to bea solitary forager, seldom encountering other otter-shrews. It makes regular underwater foraging dives that maylast for 2-5 minutes; destressed individuals can remain submergedfor up to 15 minutes.

Status and Conservation. Classified as Near Threatened on The IUCNRed List, but will be uplisted to Vulnerable in 2018. The Nimba Otter-shrew has a global extent of occurrence ofjust 14,725 km?, centered on Mount Nimba, with two small outlying populations (Sérédou in Guinea and Putu Hills in Liberia). It is currently under threat mostly from habitat loss and degradation. Its mountain stream habitat is under increasing pressure from slash-and-burn agriculture and mining. Mining activities, in particular, negatively affect presence of the Nimba Otter-shrew, presumably by clearing riparian vegetation and introducing sediments that increase turbidity of water.

Bibliography. Decher et al. (2016), Guth et al. (1959, 1960), Kuhn (1964, 1971), Monadjem et al. (2018), Vogel (1983, 2013b).

Figures

1. Nimba Otter-shrew (Micropotamogale lamotte), 2. Rwenzor Otter-shrew (Micropotamogale ruwenzorii), 3. Giant Otter-shrew (Potamogale velox)

Distribution. Endemic to the Upper Guinea rainforest zone with its distribution centered on Mt Nimba (SE Guinea, N & E Liberia, and E Ivory Coast).