655.

Strong-tailed Oldfield Mouse

Thomasomys ischyrus

French: Thomasomys a queue forte / German: Langschwanz-Paramomaus / Spanish: Raton de erial de cola fuerte

Other common names: Long-tailed Thomasomys

Taxonomy. Thomasomys cinereus ischyrus Osgood, 1914, Tambo Almirante, 65 km E Chachapoyas, near Uchco, Amazonas, Peru.

Southern population of 7 ischyrus from Cordillera de Carpish, Huanuco Region, has disjunct distribution and might represent an undescribed species. Monotypic.

Distribution. E slope of Andes of N & C Peru.

Descriptive notes. Head-body 132-138 mm, tail 151 mm, ear 23 mm, hindfoot 30-31 mm. No specific data are available for body weight. Dorsum of the Strong-tailed Oldfield Mouse is rich burnt umber, finely sprinkled with sooty tones; venter is washed with fulvous brown and not countershaded. Ears are blackish, and hair near inner bases of ears have whitish roots. Mystacial vibrissae are moderately long, extending slightly beyond posterior margin of pinnae when bent. Dorsal surface of metatarsals is brownish, contrasting with whitish digits; gap is present between thenar and hypothenar pads. Hallux is moderately long, and claw does not extend more than about one-half the length offirst phalanx of second digit. Tail is 100-121% of head-body length and bicolored, dull brownish above and scarcely lighter below, and lacks terminal white tip.

Habitat. Pristine humid montane forests and disturbed forests near potato crops in Cordillera de Carpish, with slender trees 10-15 m high, densely covered by orchids, bromeliads, ferns, lichens, and mosses; montane forests with low and high canopies, with trees 15-20 m high, covered with orchids, bromeliads, and tree ferns ( Cyathea, Cyatheaceae) at Huiquilla (Amazonas Region); elevations of 2280-3350 m.

Food and Feeding. No information.

Breeding. No information.

Activity patterns. No information.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Vulnerable on The IUCN Red List. The Strongtailed Oldfield Mouse is restricted to a very narrow elevational range on eastern flanks of the Andes, whereits estimated area of occupancy is less than 2000 km?. Its distribution is severely fragmented, and there is continuing decline in extent and quality of its habitat.

Bibliography. Beltran & Salinas (2010), Eisenberg & Redford (1999), Johnson (1972), Lee et al. (2011), Leo & Romo (1992), Musser & Carleton (2005), Osgood (1914b), Pacheco (2003, 2015b), Pacheco & Vargas (2008c¢), Pacheco et al. (2009).