Abrocoma cinerea Thomas 1919

5.

Ashy Chinchilla Rat

Abrocoma cinerea

French: Abrocome cendré / German: Graue Chinchillaratte / Spanish: Rata chinchilla cinérea

Taxonomy. Abrocoma cinerea Thomas, 1919,

“Cerro Casabindo, 4800 m,” Jujuy, Argentina.

Abrocoma cinerea is one of six allopatric species in the “ A. cinerea complex” that were formerly classified as subspecies. Older literature does not always distinguish among them, and early observations of Ashy Chinchilla Rats may refer to taxa now recognized as other species. These can be distinguished by locality. Monotypic.

Distribution. S Peru (Arequipa, Puno, Tacna), S through SW Bolivia (La Paz, Oruro, Potosi, Tarija), to NW Argentina (Jujuy, Salta, Tucuman, Catamarca) and N Chile (Arica y Parinacota, Tarapaca, Antofagasta).

Descriptive notes. Head-body 157-196 mm, tail 50-96 mm, ear 22-30 mm, hindfoot 23-30 mm; weight 90-105 g. Dorsal fur of the Ashy Chinchilla Rat is tipped in pale gray above, imparting an overall pale gray appearance; venter is whitish with gray hair bases.

Dorsal fur is dense and long (¢.33 mm) and has 25-80% greater insulation index than that of other high-elevation or arctic mammals. Tail of the Ashy Chinchilla Ratis the shortest in the genus, and it is bicolored, pale gray above and whitish below. All feet are white above. There are two pairs of mammae: one axillary and the otherlaterally on the abdomen. Greatest length of skull is 41-47 mm.

Habitat. Rocky habitats with Festuca spp. (Poaceae); shrubs (e.g. creosote bush, Larrea spp-, Zygophyllaceae); tola (Parastrephia lepidophylla), Lepidophyllum spp., and Senecio spp.

(all Asteraceae); and cushion plants in its southern distribution (Chile). Ashy Chinchilla Rats are found only in the Puna biome of the high Andesat elevations of 3700-5000 m.

Food and Feeding. The Ashy Chinchilla Ratis a folivore. It ate leaves of Senecio, tola, and Baccharis microphylla (Asteraceae) at a site in Antofagasta, and of B. boliviensis (73-4%), Lupinus ananeanus, Fabaceae (15-4%), and Atriplex sp., Amaranthaceae (0-5%) at another locality. These values suggest specialization. In Peru, a caught Ashy Chinchilla Rat fed on leaves of tola, Polylepis (Rosaceae), Senecio, and Azorella (Apiaceae). Captured individuals preferred to eat flowers and branch tips.

Breeding. Litter size of the Ashy Chinchilla Rat is 2-3 young, and pregnant or lactating females are reported in August-December. Reported gestation of 115-118 days is exceptionally long for a rodent.

Activity patterns. There is no specific information for this species, but the Ashy Chinchilla Ratis probably nocturnal.

Movements, Home range and Social organization. Ashy Chinchilla Rats live in small colonies under rocks and in rock clefts, below which they establish latrines of dried feces and urine. Burrows with entrances of ¢.5 cm in diameter occur near rock outcrops, under shrubs, or in stone walls. Ashy Chinchilla Rats use paths that lead away from their burrows at least as far as 200 m.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Ashy Chinchilla Rat does not face conservation threats of concern.

Bibliography. Cortés et al. (2002), Koford (1955), Spotorno et al. (1998).