471.

Crafty Marsh Rat

Holochilus vulpinus

French: Oryzomys fauve / German: Schlaue Sumpfratte / Spanish: Rata de marisma astuta

Taxonomy. Mus vulpinus Brants, 1827, Brazil. Restricted by R. Cerqueira in 1975 to the banks of Rio Uruguay, between Itaqui and Uruguay, Rio Grande do Sul, Brazil. This species is monotypic.

Distribution. E Paraguay, NE & EC Argentina, S Brazil, and Uruguay.

Descriptive notes. Head-body 141-238 mm, tail 160-238 mm, hindfoot 41-65 mm; weight 308-5 g (mean). See general characters of the genus under the Venezuelan Marsh Rat ( H. venezuelae) account. Dorsum of the Crafty Marsh Rat is reddish to brown, and venter is white or sometimes orangish, with white throat and chest. Hindfeet have interdigital webbing. Skull is heavily built. Interorbital margins have moderately well-developed supraorbital crests. Incisors are opisthodont; molars are tetralophodont. Chromosomal complement is 2n = 35-39, FN = 57-61.

Habitat. Wetlands and agricultural fields in Atlantic Forest and Pampas biomes.

Food and Feeding. The Crafty Marsh Rat eats riparian and aquatic vegetation and agriculture crops.

Breeding. Nests of Crafty Marsh Rats are built up to 2-3 m above water level with hygrophilous vegetation or vines. Numbers of embryos are 2—4/litter.

Activity patterns. No information.

Movements, Home range and Social organization. No information.

Status and Conservation. Not assessed on The IUCN Red Lust.

Bibliography. Cerqueira (1975), Formoso et al. (2010), Goncalves et al. (2015), Massoia (1971c, 1976), Nachman (1992a, 1992b), Nachman & Myers (1989), Waterhouse (1839).