Ichthyomys tweedii Anthony 1921

347.

Tweedy’s Crab-eating Rat

Ichthyomys tweedii

French: Ichthyomys de Tweedy / German: Tweedy-Krabbenratte / Spanish: Rata cangrejera de Tweedy

Other common names: Tweedy'’s Ichthyomyine

Taxonomy. Ichthyomys tweedii Anthony, 1921, “Portovelo, Prov. del Oro, Ecuador; alttude, 2000 ft. [= 610 m].”

It includes I. caurinus which is treated as junior synonym of I. tweedii. Monotypic.

Distribution. C Panama and lowlands and Andean foothills of W Ecuador.

Descriptive notes. Head-body 143-197 mm, tail 132-155 mm, ear 8-12 mm, hindfoot 33-40 mm; weight 123-155 g. Large ichthyomyine, with dark unicolored tail, bilobed M,, and massive skull featuring broad rostra and flaring zygomatic arches. Dorsal pelage is dense and woollylooking. Back is dark brown; flanks are paler; and venter is white to yellowish gray, strongly contrasting flanks and back. Tail is uniformly dark brown, equal or somewhat smaller than head-body length. Outer edges of feet and fingers have fringes of rigid silver-to-white hair.

Habitat. Small streams bordered by dense secondary vegetation from sea levelto elevations of ¢.1350 m.

Food and Feeding. Tweedy’s Crab-eating Rat eats fish, crabs, and aquatic insects.

Breeding. A Tweedy’s Crab-eating Rat collected during late wet season (May) had two newly implanted embryos in utero.

Activity patterns. Tweedy’s Crab-eating Rat is both diurnal and nocturnal, and semiaquatic.

Movements, Home range and Social organization. Tweedy’s Crab-eating Rats are solitary.

Status and Conservation. Classified as Data Deficient on The IUCN Red List. Extent of occurrence, status, and ecological requirements of Tweedy’s Crab-eating Rat are unknown. It could more widely distributed because it is known from two disjunct areas.

Bibliography. Anthony (1921), Santillan & Segovia (2013), Thomas (1924b), Tirira, Boada, Samudio & Pino (2008), Voss (1988, 2015b), Voss et al. (1982).