434.

Sandy Pygmy Rice Rat

Oligoryzomys arenalis

French: Colilargo des sables / German: Sand-Zwergreisratte / Spanish: Rata arrocera pigmea de arena

Other common names: Sandy Colilargo

Taxonomy. Oryzomys arenalis Thomas, 1913, Etén, Lambayeque, Peru.

Taxonomy uncertain. Nomenclatorial status with respect to Mus peruvianus Peale, 1848, tenously allied to Oligoryzomys by several authors, was formally solved with the recent selection of a lectotype belonging to Mus musculus from the material collect ed by the famous US Exploring Expedition. However, in the original description, T. R. Peale (page 51) recorded the length of the tail of peruvianus as larger than the head-body, a measurement hard to reconciliate with typical M. musculus . Monotypic.

Distribution. Coastal plains of W Peru.

Descriptive notes. Head—body 80 mm, tail 100 mm, hindfoot 21 mm (holotype). No specific data are available for body weight. The Sandy Pygmy Rice Rat is one of the smallest species of Oligoryzomys . Dorsum is clay over underlying buffy, lined with dark brown; head is slightly grayer and less buffy; sides are buffy, with somewhat buffy line separating dorsum and venter; underparts are creamy white, with slight buffy tint and slaty bases to hairs; ear are only slightly darker than dorsum; chin is white; dorsal surfaces of forefeet and hindfeet are white; and tail is long and bicolored, brown above and creamy white below.

Habitat. Arid and semiarid coastal plain; restricted to hydromorphic vegetation patches close to rivers and lagoons at edges of small swamps or irrigating ditches.

Food and Feeding. No information.

Breeding. No information.

Activity patterns. No information.

Movements, Home range and Social organization. No information.

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

Bibliography. Fisher & Ludwig (2014), Musser & Carleton (2005), Osgood (1914b), Peale (1848), Tate (1932e), Trouessart (1897), Weksler & Bonvicino (2015b), Zeballos & Vivar (2016b), Zeballos et al. (2001).