545.

Northern Akodont

Necromys urichi

French: Akodon d'Urich / German: Nordliche Graslandmaus / Spanish: Raton cavador septentrional

Other common names: Northern Grass Mouse

Taxonomy. Akodon urichi J. A. Allen & F. M. Chapman, 1897, Caparo, Trinidad, Trinidad and Tobago.

Necromys urichi is the type species of subgenus Chalcomys, currently considered a synonym of Necromys . As presently understood, N. wurichi is a composite of several taxa. On morphological grounds, N. urichi is the most divergent species of Necromys .

Monotypic.

Distribution. Colombia, Venezuela, Trinidad and Tobago Is, and W Guyana; possibly extreme N Brazil.

Descriptive notes. Head-body 107-141 mm, tail 69-102 mm, ear 16-19 mm, hindfoot 22-29 mm; weight 30-61 g. See general characters of the genus under the Ecuadorean Akodont (N. punctulatus) account. The Northern Akodont is a small species of Necromys . Dorsum is dark rusty chestnut, finely intermixed with black; venter is washed with yellowish or has pale to medium gray tips, but always with dark-based hairs; hair tips of chin, throat, and around inguinal area are gray in most specimens; and eye-ring is present. Ears are dark brown, thinly covered with short, dark rusty brown hair; tail is slightly more than one-third the total length, uniformly dark, sparsely haired, and without tuft. Manus and pes are covered dorsally with short, dark ocherous hairs; and ungual tufts are present on forefeet and hindfeet. In contrasting with other species of Necromys (2n = 34), diploid number of the Northern Akodont is 2n = 18.

Habitat. Savannas and evergreen, cloud, deciduous, and premontane humid forests.

Food and Feeding. The Northern Akodont eats succulent vegetation and seeds.

Breeding. Reproduction of the Northern Akodont occurs year-round, with peak in May-June at onset of rainy season. Average littersize is five young. Sexual maturity is reached at 2:7 months old.

Activity patterns. The Northern Akodont is terrestrial and active day and night.

Movements, Home range and Social organization. In premontane humid forest of the Coastal Range in Venezuela, a 22month study found mean density of 2-9 ind/ha (range 0-6-5-9 ind/ha) and a mean residence time ofjust over three months for males and four months for females. The population was slightly female biased (1: 1-2), and estimated juvenile survivorship was 55%.

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

Bibliography. Aagaard (1982), Eisenberg & Redford (1999), Gémez-Laverde, Anderson et al. (2016), Handley (1976), Lim (2016), Linares (1998), O'Connell (1989), Pardinas, Teta, Ortiz et al. (2015), Reig et al. (1971), Ventura et al. (2000), Voss (1992).