335.

Musso’s Fish-eating Rat

Neusticomys mussoi

French: Ichthyomys de Musso / German: Musso-Fischratte / Spanish: Rata pescadora de Musso

Other common names: Musso's Ichthyomyine

Taxonomy. Neusticomys mussoi Ochoa & Soriano, 1991, Paso Hondo, Rio Potosi, 14 km SE Pregonero, Tachira, Venezuela. This species is monotypic.

Distribution. Known only from three localities in Andean N Colombia and W Venezuela.

Descriptive notes. Head-body 94-118 mm, tail 75-82 mm, ear 86-10 mm, hindfoot 21 mm. No specific data are available for body weight. Musso’s Fish-eating Rat is one of the smallest species of Neusticomys . Dorsal fur is bright brownish, dense, soft, and ¢.6 mm long, with reddish brown tips and scattered longer hairs (c.8 mm long) with black tips. Ventral fur is shorter (c.4 mm long) and paler than dorsal fur and slightly grayer, with longerscattered hairs (c.6 mm long) having golden tips. Hindfeet are narrow and c.21 mm long, with shorter fringing hair and interdigital webs. Manus is cream-colored on dorsal and ventral sides, with three separate interdigital pads and two separate carpal pads; pollex is highly reduced and below lower level of first interdigital pad. Pale cream fur is in ears and on feet. Mystacial vibrissae are short, sparse, soft, and entirely whitish. Philtrum is present, and pinnae are conspicuous, small, rounded, and furred on both sides, with inside part yellowish, contrasting color of dorsalfur. Tail is shorter than head-body length, densely covered by dark-brownish hairs and with patch of entirely white hairs at tip.

Habitat. Streams bordered by montane semideciduous forest. A Colombian Musso’s Fish-eating Rat was trapped in a pitfall set 10 m from the margin of a small creek surrounded by dense riparian forest with litter cover ¢.90%.

Food and Feeding. Musso’s Fish-eating Rat probably feeds on relatively large arthropods with heavily sclerotized exoskeletons.

Breeding. No information.

Activity patterns. Musso’s Fish-eating Rat is probably nocturnal and semi-aquatic.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Endangered on The IUCN Red List. Musso’s Fisheating Rat occurs in less than 5000 km?, with declining habitat quality. It is only known from fewer than five locations.

Bibliography. Ochoa & Soriano (1991, 2008), Rodriguez-Posada (2014), Voss (1988, 2015b).