659.

Inca Oldfield Mouse

Thomasomys incanus

French: Thomasomys inca / German: Inka-Paramomaus / Spanish: Raton de erial de los Incas

Other common names: Black-eared Thomasomys, Inca Thomasomys

Taxonomy. Oryzomys incanus Thomas, 1894, “Valley of Vitoc [Junin], Central Peru.”

Thomasomys incanus could represent a species complex due to broad geographic distribution and intraspecific variation among populations. Monotypic.

Distribution. E slope of the Andes in N & C Peru, between San Martin and Junin regions.

Descriptive notes. Head-body 111-134 mm, tail 125 mm, ear 18-21 mm, hindfoot 22-28 mm. No specific data are available for body weight. Dorsum of the Inca Oldfield Mouse is grizzled brownish gray; venter is rather dirty fulvous and not countershaded. Mystacial vibrissae are moderately long and extended slightly beyond posterior margin of pinnae when bent. On plantar surfaces of hindfeet, gap occurs between thenar and hypothenar pads, and another gap occurs between hypothenar and fourth digital pad. Hair above metatarsals and digits is silvery white. Hallux is moderately long, with claw extended close to interphalangeal of second digit; claw offifth digit is extended to interphalangealjoint of fourth digit. Tail is relatively short (92-110% of head-body length), finely annulated with disperse short hairs, slightly bicolored, dark brownish above and paler below, and without whitish terminaltip.

Habitat. Montane forest at elevations of 2430 m-3850 m. Some Inca Oldfield Mice from Pasco and Huanuco were recorded in dense humid forests near streams, and some from San Martin were recorded in paramo vegetation, under rocks in grassland or scrub vegetation, in fragmented and continuous forest, and near streams either on riverine vegetation or on sandy banks.

Food and Feeding. No information.

Breeding. No information.

Activity patterns. The Inca Oldfield Mouse is nocturnal.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Vulnerable on The IUCN Red List. The Inca Oldfield Mouse occurs in less than 20,000 km?, with severe fragmentation and continuous decline in extent and quality ofits habitat.

Bibliography. Bergsten (2005), Cabrera (1961), Ellerman (1941), Leo & Romo (1992), Musser & Carleton (1993, 2005), Osgood (1933c), Pacheco (2003, 2015b), Pacheco & Vargas (2008b), Pacheco et al. (2009), Thomas (1927d).