486.

Atlantic Water Rat

Nectomys squamipes

French: Nectomys atlantique / German: Atlantische Wasserratte / Spanish: Rata de agua atlantica

Other common names: Atlantic Forest Nectomys, South American Water Rat

Taxonomy. Mus squamipes Brants, 1827, “ Brasilien.” Restricted by P. Hershkovitz in 1944 to “Sao Sebastiao, Sao Paulo, Brazil.” This species is monotypic.

Distribution. E Brazil (along Atlantic Forest from Pernambuco to Rio Grande do Sul states), E Paraguay, and NE Argentina (Misiones Province).

Descriptive notes. Head-body 119-258 mm, tail 122-287 mm, ear 15-35 mm, hindfoot 35-62 mm; weight 112-380 g. See general characters of the genus under the Trinidad Water Rat (N. palmipes) account. Dorsum of the Atlantic Water Ratis ocherous orange, mixed with brown; underparts are pale gray, mixed with orange or pale yellow; orbital ring is poorly defined; ears are brown; and tail is uniformly brown. Skull is heavy built and robust. Chromosomal complement varies according to presence of B chromosomes at 2n = 56-59, FN = 56-58 and 62.

Habitat. Primary forests along watercourses.

Food and Feeding. The Atlantic Water Rat eats fungi, small vertebrates, invertebrates, leaves, and fruits.

Breeding. In captivity, gestation is 30 days, and females have postpartum estrus. Litters have 1-6 young; weaning occurs at 20-25 days old; and females reach sexual maturity at c.75 days old.

Activity patterns. The Atlantic Water Rat is nocturnal.

Movements, Home range and Social organization. Home ranges of Atlantic Water Rats are 2200-12,000 m?. Densities are 1:2-3-4 ind/ha.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Atlantic Water Rat has a wide distribution and presumably large overall population and is tolerant of some habitat disturbance.

Bibliography. Alho (1982), Bonvicino & Weksler (2015), Briani et al. (2001), Crespo (1982), D'Andrea et al. (1996), Davis (1947), Ernest (1986), Hershkovitz (1944), Moojen (1952), Musser & Carleton (2005), Prevedello et al. (2010), Vieira et al. (2016).