505.

Dusky Rice Rat

Melanomys caliginosus

French: Mélanomys sombre / German: Dunkelreisratte / Spanish: Rata arrocera oscura

Other common names: Dusky Melanomys

Taxonomy. Hesperomys caliginosus Tomes, 1860, Esmeraldas, Esmeraldas, Ecuador.

M. caliginosus includes Oryzomys phaeopus Thomas, 1894, type species of the genus Melanomys Thomas, 1902 . Several nominal forms are currently subsumed under M. caliginosus, including Oryzomys phaeopus, O. phaeopus obscurior, O. phaeopus olivinus, O. ( Melanomys) obscurior affinis, Melanomys caliginosus oroensis, M. affinis monticola, M, phaeopus vallicola, M. phaeopus tolimensus, M. lomitensis, and M. buenavistae. As for the entire genus, taxonomy in M. caliginosus needs a comprehensive revision. Monotypic.

Distribution. WC Colombia S to SW Ecuador.

Descriptive notes. Head—body 100-140 mm, tail 70-111 mm, ear 16 mm, hindfoot 24-28 mm. The Dusky Rice Rat is geographically variable but overall very dark dorsally. See general characters of the genus under the Black-and-Yellow Rice Rat ( M. chrysomelas) account. Upperparts are brown washed, rather pale yellow and finely lined with black, especially along middle of back; underfur is grayish plumbeous, with hairs black basally; sides are less dark and more yellowish than middle of back; venteris pale gray at base, tipped with pale buffy yellow, forming heavy conspicuous yellow wash; tail, ears, and feet are dark brown; and tail is naked, faintly lighter below than above.

Habitat. Andean and Pacific forests from sea level to elevations of ¢.2300 m.

Food and Feeding. No information.

Breeding. In Choc6, Colombia, reproductively active Dusky Rice Rats were recorded in March; a pregnant female gave birth to two young.

Activity patterns. The Dusky Rice Ratis terrestrial.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Least Concern on The IUCN Red List.

Bibliography. Allen (1913b), Cadena et al. (1998), Cassola (2016ab), Hanson & Bradley (2008), Thomas (1902d), Weksler & Loss (2015).