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Ethiopian Amphibious Rat

Nilopegamys plumbeus

French: Rat d'Ethiopie / German: Athiopische Waldbachmaus / Spanish: Rata de agua de Etiopia Other common names: Ethiopian Water Mouse, Ethiopian Water Rat

Taxonomy. Nilopegamys plumbeus Osgood, 1928,

“from small stream tributary to the Little Abbai, between Sakalla and Njabarra, Gojam, Abyssinia [= NW Ethiopia].”

Because of its derived morphology, genus Nilopegamys has not yet been placed in a Murinae tribe. Following its initial description, it was considered a valid species by some authors and a subspecies of Colomys goslingi by others. J. C. Kerbis Peterhans and B. D. Pattersonprovided a full description of the holotype in 1995, and showed that it differs from Colomys in multiple morpho-anatomical characteristics. P. H. Fabre and colleagues in 2015 found it possibly a member of tribe Praomyini, as did C. Denys and coworkers two years later. Monotypic.

Distribution. Known only from the type locality on the Ethiopian highlands.

Descriptive notes. Head-body 148 mm, tail 180 mm, ear 14-4 mm, hindfoot 40 mm; weight 80 g. Medium-sized rodent adapted to aquatic life, the Ethiopian Amphibious Rat has very soft grayish-black dorsal pelage and pure white belly. Head is long, and muzzle bulbous with long vibrissae. Ears are small, and there are postauricular spots. Hands and feet are white, long and broad. Tail is very long (120% of head-body length), with black tip, and is bicolored (black above, white below with thin black median line). Skull is flat, braincase rather large (enlarged brain), and foramen magnum enlarged.

Habitat. Recorded from highland, riparian habitat at 2800 m.

Food and Feeding. Probably smallfish.

Breeding. No information.

Activity patterns. The Ethiopian Amphibious Rat is thought to be terrestrial and semiaquatic.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Critically Endangered on The IUCN Red List but could be soon declared extinct. The Ethiopian Amphibious Rat is known from a single individual collected in 1927; despite many searches, it has not been found again. Its original habitat has been destroyed and is now overgrazed by cattle.

Bibliography. Denys et al. (2017), Fabre et al. (2015), Happold (2013a), Kerbis Peterhans & Patterson (1995), Monadjem et al. (2015), Musser & Carleton (2005).