501.

Harris's Rice Water Rat

Tanyuromys aphrastus

French: Mélanomys a longue queue / German: Harris-Reiswasserratte / Spanish: Rata de agua de Harris

Other common names: Long-tailed Montane Rat, Long-tailed Sigmodontomys

Taxonomy. Oryzomys aphrastus Harris, 1932, San Joaquin de Dota, 1219 m, San José Province, Costa Rica.

Tanyuromys aphrastus is the type species of the genus. Monotypic.

Distribution. SE Costa Rica, W Panama, W Ecuador; and probably Colombia.

Descriptive notes. Head-body 116-152 mm, tail 176-235 mm, ear 17 mm, hindfoot 35-40 mm; weight 63 g. Harris’s Rice Water Rat is a medium-sized, very long-tailed oryzomyine, with long and robust hindfeet. Pelage is long and soft, upperparts are grizzled dark brown with orange highlights, and underparts are paler gray, with pronounced ocherous highlight. Dorso-ventral countershading is subtle. Ears are small and sparsely to moderately covered with blackish, dark brown, or reddish brown hair. Mystacial and superciliary vibrissae are very long. Manus and pes have sparse to moderate cover of pale brown to dark brown hairs dorsally. Hindfeet lack well-developed natatory fringes and interdigital webs and have sparse ungual tufts covering tips of claws. Tail is unicolored brown and sparsely haired, terminating in short tuft. Four pairs of mammae are present.

Habitat. Mature primary or secondary forests at elevations of 1200-2500 m. Habitat of Harris’s Rice Water Rat is characterized by lush evergreen forests where canopy height and continuity decrease with elevation and epiphyte and moss cover increase with elevation. Where an adult was caught in Monteverde Cloud Forest Reserve, Costa Rica, forest had a tall, somewhat broken canopy (15-30 m), with heavy epiphyte and moss growth and multilayered understory of ferns, shrubs, herbs, young trees, and monocots.

Food and Feeding. Molars of Harris’s Rice Water Rat have unique occlusal pattern, with tendency to lophodonty and probably associated with some degree of herbivory.

Breeding. No information.

Activity patterns. Harris’s Rice Water Rat is terrestrial; all collected specimens were trapped on ground.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Data Deficient on The IUCN Red List (as Sigmodontomys aphrastus).

Bibliography. Brito & Arguero (2016), Harris (1932), Hershkovitz (1944), Lee et al. (2010), McCain et al. (2007), McPherson (1985), Pine et al. (2012), Samudio et al. (2008), Voss (1988), Weksler (2015c¢).