646.

Golden Oldfield Mouse

Thomasomys aureus

French: Thomasomys doré / German: Gold-Paramomaus / Spanish: Raton de erial dorado

Other common names: Golden Thomasomys

Taxonomy. Hesperomys aureus Tomes, 1860, type locality not given. According to R. S. Voss in 1993, the type locality is uncertain.

Thomasomys aureus might represent a species complex. Monotypic.

Distribution. Andes, from W Venezuela, C & SW Colombia, Ecuador, and Peru to WC Bolivia.

Descriptive notes. Head-body 142-180 mm, tail 172-250 mm, ear 20-29 mm, hindfoot 33-40 mm; weight 75-175 g. Dorsum of the Golden Oldfield Mouse is yellowish brown to reddish brown. Venteris yellowish pale gray to whitish, with stripe or yellow spot on chest, throat, and cheeks. Pelage is soft, fine, dense, and long, usually more than 10 mm in midline of back and toward tail. Uniform or bicolored tail is thick and long, reaching ¢.130% of head-body length. Hairs on back and belly are bicolored, always with bases of gray to dark gray. Eyes are small, and ears are medium-sized, well-rounded, and dark brown, barely covered by small, blackish hair that do not contrast with color of head. Vibrissae are thin, black, and long, reaching a little further behind ears when tilted. Hindfeet are moderately long and broad, with silvery, brown, or blackish hair on upper faces and black soles. Fifth digit is semi-usable.

Habitat. Primary forests, secondary forests, human modified areas, and near human habitation at elevations of 1460-3850 m. Golden Oldfield Mice prefer forests with abundant bushy vegetation, high humidity, and rich in humus. In the moors, they occupy areas covered with grass or near rock walls and water bodies. In north-western Ecuador, they are abundant in and strong select for Polylepis (Rosaceae) forest.

Food and Feeding. The Golden Oldfield Mouse eats fruit, seeds, other plant material, and insects, with a preference for Passiflora (Passifloraceae) fruit. In north-western Ecuador, some individuals ate tender shoots of Aetheolaena patens and Dendrophorbium tipocochense ( Asteraceae) in middle and upper vegetation strata of the forest.

Breeding. In Peru, male Golden Oldfield Mice with descended testes and females with 2-3 embryos were recorded in September. In north-western Ecuador, reproduction occurs year-round, although it is more frequently in dry season.

Activity patterns. The Golden Oldfield Mouse is nocturnal and arboreal, moving through the forest canopy; it occasionally falls to the ground when the canopy is discontinuous.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Golden Oldfield Mouse is infrequently caught, suggesting it is rare or difficult to record.

Bibliography. Anderson (1997), Barnett (1999), Brito, Teska & Ojala-Barbour (2012, 2015), Eisenberg et al. (1979), Gardner & Romo (1993), Handley (1976), Jarrin (2001), Leo & Romo (1992), Linares (1998), Musser & Carleton (1993, 2005), Pacheco (2003, 2015b, 2016a), Sahley et al. (2015), Salas et al. (2013), Salazar-Bravo & Yates (2007), Thomas (1900c), Tirira (2007), Tomes (1860), Voss (1993, 2003).