678.

Red-nosed Tree Mouse

Wilfredomys oenax

French: Wilfredomys / German: Wilfred-Maus / Spanish: Raton arboricola de hocico rojo

Other common names: Greater Wilfred's Mouse, Rufous-nosed Wilfredomys

Taxonomy. Thomasomys oenax Thomas, 1928, Sao Lourenco do Sul, Rio Grande do Sul, Brazil.

Wilfredomys oenax is the type species of the genus. Subtle differences have been highlighted between Brazilian and Uruguayan populations. Monotypic.

Distribution. Known from a few scattered localities in SE & S Brazil (from Sao Paulo to Rio Grande do Sul states) and N Uruguay.

Descriptive notes. Head-body 119-130 mm, tail 161-211 mm, ear 22 mm, hindfoot 30-5-35 mm; weight 42-62 g. The Red-nosed Tree Mouse is medium-sized and brightly colored. Dorsum is orange-brown, with light yellow to orange short hairs and dark brown to black-tipped long hairs. Rump is often ocherous orange due to distally orange hairs. Ears and nose are covered by very short, ocherous, and ocherous-rufous hairs. Venteris lighter than dorsum, without clear demarcation between them. Hair is whitish on throat and inguinal regions. Mystacial vibrissae are dark and long, reaching posterior limit of pinnae. Upper surface of manus and pes are covered by mix of whitish and ocherous hairs. Claws are inconspicuous. Tail looks naked, brown above and slightly paler below, and is finely annulated, with pencil of 2-3 mm attip.

Habitat. Gallery and montane forest. Red-nosed Tree Mice were trapped in a canyon with mesic subtropical woodland among large rocks in the forest or in branches 1-5-2 m aboveground.

Food and Feeding. Stomachs had greenish plant material, trapping bait, and purplish berries from aruera ( Lithraea molleoides, Anacardiaceae). The Red-nosed Tree Mouse has a well-developed cecum, suggesting the consumption of vegetable matter.

Breeding. Male Red-nosed Tree Mice have been captured in winter in breeding condition, with testes measuring 10 x 6 mm containing abundant mature sperm in epididymides.

Activity patterns. The Red-nosed Tree Mouse is nocturnal and arboreal, and uses abandoned bird’s nests.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Endangered on The IUCN Red List. Forest habitats of the Red-nosed Tree Mouse are severely fragmented.

Bibliography. de Avila-Pires (1960b), Barlow (1969), Bonvicino, Oliveira & DAndrea (2008), Gonzalez & Martinez (2010), Gonzalez et al. (2015), Machado et al. (2015), Pine (1980), Thomas (1928), Vaz (1960), Vieira & Christoff (2008).