Thomasomys incanus (Thomas, 1894)

Don E. Wilson, Russell A. Mittermeier & Thomas E. Lacher, Jr, 2017, Cricetidae, Handbook of the Mammals of the World – Volume 7 Rodents II, Barcelona: Lynx Edicions, pp. 204-535 : 500-501

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).

Figures

622. Unicolored Oldfield Mouse (Thomasomys monochromos), 623. Venezuelan Oldfield Mouse (Thomasomys emeritus), 624. Dressy Oldfield Mouse (Thomasomys vestitus), 625. Woodland Oldfield Mouse (Thomasomys hylophilus), 626. Niceforo Maria’s Oldfield Mouse (Thomasomys nicefor), 627. Popayan Oldfield Mouse (Thomasomys popayanus), 628. Shortfaced Oldfield Mouse (Thomasomys baeops), 629. Snow-footed Oldfield Mouse (Thomasomys niveipes), 630. Principal Oldfield Mouse (Thomasomys princeps), 631. Silky Oldfield Mouse (Thomasomys bombycinus), 632. Red Andean Oldfield Mouse (Thomasomys auricularis), 633. Cinnamon-colored Oldfield Mouse (Thomasomys cinnameus), 634. Central Andes Oldfield Mouse (Thomasomys contradictus), 635. Ashy-bellied Oldfield Mouse (Thomasomys cinererventer), 636. Colombian Oldfield Mouse (Thomasomys dispar), 637. Soft-furred Oldfield Mouse (Thomasomys laniger), 638. Ash-colored Oldfield Mouse (Thomasomys cinereus), 639. Wandering Oldfield Mouse (Thomasomys erro), 640. Paramo Oldfield Mouse (Thomasomys paramorum), 641. Forest Oldfield Mouse (Thomasomys silvestris), 642. Smoky Oldfield Mouse (Thomasomys fumeus), 643. Pichincha Oldfield Mouse (Thomasomys vulcani), 644. Ucucha Oldfield Mouse (Thomasomys ucucha), 645. Taczanowski’s Oldfield Mouse (Thomasomys taczanowsku), 646. Golden Oldfield Mouse (Thomasomys aureus), 647. White-tipped Oldfield Mouse (Thomasomys caudivarius), 648. Hudson's Oldfield Mouse (Thomasomys hudsoni), 649. Reddish-backed Oldfield Mouse (Thomasomys pyrrhonotus), 650. Montane Oldfield Mouse (Thomasomys oreas), 651. Cajamarca Oldfield Mouse (Thomasomys praetor), 652. Distinguished Oldfield Mouse (Thomasomys notatus), 653. Apeco Oldfield Mouse (Thomasomys apeco), 654. Peruvian Oldfield Mouse (Thomasomys eleusis), 655. Strong-tailed Oldfield Mouse (Thomasomys ischyrus), 656. Reddish-nosed Oldfield Mouse (Thomasomys rosalinda), 657. Large-eared Oldfield Mouse (Thomasomys macrotis), 658. Ashaninka Oldfield Mouse (Thomasomys onkiro), 659. Inca Oldfield Mouse (Thomasomys incanus), 660. Kalinowski’s Oldfield Mouse (Thomasomys kalinowskii), 661. Slender Oldfield Mouse (Thomasomys gracilis), 662. Daphne’s Oldfield Mouse (Thomasomys daphne), 663. Anderson’s Oldfield Mouse (Thomasomys andersoni), 664. Austral Oldfield Mouse (Thomasomys australis), 665. Ladew’s Oldfield Mouse (Thomasomys ladewi)

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