754.

Andean Big-eared Mouse

Auliscomys sublimis

French: Phyllotis de | 'Altiplano / German: Anden-GroRohrmaus / Spanish: Raton de orejas grandes de los Andes

Other common names: Lofty Pericote

Taxonomy. Phyllotis sublimis Thomas, 1900, “Rinconado Malo pass, above Cayl-loma, on the Sumbay road, Peru. Altitude 5500 metres (nearly 18,000 feet).”

O. Thomas in 1900 noted, “This most interesting little mouse [ sublimis] lives at the highest altitude from which mammalian life has been recorded in the New World, and in the Old is only surpassed in this respect by a few of the Himalayan species.” O. P. Pearson, an expert on Peruvian mammals and landscapes, cautioned in 1951, “If the altitude ofcollection of the type and topotypes of P. sublimis sublimis is correctly stated on the labels and in the type description (18,000 feet), then this species lives at the highest elevation recorded for mammals in the Western Hemisphere.” With currently available technology, the road between Caylloma and Sumbay, c.50 km of high-elevations Altiplano, was checked; the highest point achieved on this road was in the vicinity of Caylloma, with an elevation of ¢.4900 m. Therefore, it seems very improbable that the type series of sublimis was collected at 5500 m; in fact, in a reasonable distance from the road, there is no a single point with above 5100 m. Two subspecies recognized.

Subspecies and Distribution.

A.s.sublimisThomas,1900—SPeru,WCBolivia,andextremeNEChile.

A. s. lewcurus Thomas, 1919 — SWBolivia, adjacent NE Chile (Antofagasta Region), and NW Argentina .

Descriptive notes. Head—body 92-118 mm, tail 49-64 mm, ear 19-23 mm, hindfoot 21-23 mm; weight 28-44 g. See general characters of the genus under the Painted Big-eared Mouse (A. pictus) account. The Andean Big-eared Mouse has fluffy fur, and short-tailed; its dorsal pelage is long, extremely soft, and fine. Overall dorsum is buffy yellow, mixed with some black hair; head is somewhat more grizzled than rest of body; no eye-ring is present; sides of body are paler, turning white on cheeks; although lateral line is usually indistinct, underparts are sharply defined whitish to pale gray, with base of fur often plumbeous; upper surfaces offorefeet and hindfeet are silvery white; and hindfeet are naked below except on heel. Tail length is always less than 68 mm; tail itself is covered with fine white hair, often distinctly bicolored, but lacking tuft at tip. Ears are short and covered with fine yellowish hair inside; distinct post-auricular patches often are present. Chromosomal complement is 2n = 28, FN = 30.

Habitat. Altiplano highlands at elevations of 3200—c.5400 m. The Andean Big-eared Mouse reportedly is common in Peruvian Altiplano and often occurs in areas with abundant vegetative cover, pastures, rocky outcrops, and Stipa-dominated scrublands, or among boulders and yareta ( Azorella compacta, Apiaceae). It can also be found in high-elevation meadows (“bofedales”).

Food and Feeding. The Andean Big-eared Mouse is reportedly a omnivore or a specialized herbivore. Consumption ofinsectsis variable and probably dependent on elevation.

Breeding. The Andean Big-eared Mouse probably breeds in the dry season. Some females were sexually precocious; females with up to five embryos were trapped in Arequipa, Peru. Males with scrotal testes were recorded in late July.

Activity patterns. The Andean Big-eared Mouse is terrestrial and nocturnal.

Movements, Home range and Social organization. The Andean Big-eared Mouse was described as gregarious, probably because the type series of nine individuals was extracted from a single burrow. It is not clearif it excavates its own burrows or just occupies abandoned tuco-tuco or guinea pig burrows. It probably estivates.

Status and Conservation. Classified as Least Concern on The IUCN Red Lust.

Bibliography. Anderson (1997), Diaz & Barquez (1999), Dunnum, Vargas, Bernal, Zeballos, Vivar, Patterson, Jayat & Pardinas (2016b), Hershkovitz (1962), Mercado & Miralles (1991), Pearson (1951a, 1958), Salazar-Bravo (2015b), Thomas (1900d, 19194).