672.

Peterson’s Chinchilla Rat

Funeomys petersoni

French: Eunéomys de Peterson / German: Peterson-Chinchillamaus / Spanish: Rata chinchilla de Peterson

Other common names: Peterson's Chincilla Mouse, Peterson's Euneomys

Taxonomy. Euneomys petersoni J. A. Allen, 1903, “upper Rio Chico de Santa Crus, near the Cordilleras, Patagonia.” Clarified by U. F. J. Pardinas in 2013 to “rio Chico, 4.5 km upstream Estancia El Portezuelo, Santa Cruz, Argentina.”

Morphological and molecular variation of populations attributed to E. petersoni suggests existence of an undescribed species. Monotypic.

Distribution. S & C Patagonia, from WC Argentina and C Chile to extreme S mainland Argentina and adjacent Chile.

Descriptive notes. Head—body 97-127 mm, tail 46-73 mm, ear 19-24 mm, hindfoot 22-27 mm; weight 26-47 g. Peterson’s Chinchilla Rat is long-furred and short-tailed; it is smaller than the Patagonian Chinchilla Rat ( E. chinchilloides). Its pelage is soft, almost woolly, and dark gray brown above variegated with blackish and fulvous streaks; sides are much paler and more fulvous, especially along lower border; belly is soiled white; ears are dark brown on both surfaces and very thinly haired; nose and upperlips are white;sides of nose and lower borders of cheeks are whitish gray, with faint tinge of yellow or pure white; soles are naked, except for posterior third; and tail is one-third or less of total head-body length, well-haired, and dusky brown above, with sides and ventral surface white. Upper incisors have lateral grooves. Two chromosomal complements have been detected: 2n = 34, FN = 62-64 and 2n = 36, FN = 64-66.

Habitat. Mostly barren, rocky, windswept slopes with little vegetation characteristic of southern Patagonia but also ecotones between Patagonian steppe and southern beech ( Nothofagus, Nothofagaceae) formations, at elevations as high as 3500 m on Cerro Aconcagua.

Food and Feeding. Peterson’s Chinchilla Rat is herbivorous. Its feces are deposited in large latrines among rocky crevices.

Breeding. Peterson’s Chinchilla Rats with reproductive signals are detected during late spring and summer (November-March). In April, ten males trapped in central Chubut Province, had testes in abdominal position, and five females showed imperforate vaginas.

Activity patterns. Peterson’s Chinchilla Rats are nocturnal and terrestrial, and live in rocky holes and large crevices.

Movements, Home range and Social organization. Peterson’s Chinchilla Rats usually live in moderately large groups.

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

Bibliography. Allen (1903b, 1905), Braun & Pardinas (2015), Greer (1965), Lessa et al. (2010), Ojeda et al. (2015), Pardinas (2013), Pardinas & D'Elia (2016b), Pearson (1983, 1987), Pearson & Christie (1991), Pine et al. (1979), Vianna et al. (2011), Reise & Gallardo (1990), Reise & Venegas (1987), Hershkovitz (1962), Yanez et al. (1987).