679.

Andean Long-clawed Mouse

Paynomys macronyx

French: Paynomys des Andes / German: Anden-Langkrallenmaus / Spanish: Raton de unas largas de los Andes

Other common names: Andean Long-clawed Akodont

Taxonomy. Acodon macronyx Thomas, 1894, “East side of the Andes, near Fort San Rafael, Province of Mendoza.” Questioned by O. P. Pearson and H. A. Lagiglia in 1992 and changed to probably near Peteroa Volcano, on the Argentinean—Chilean border.

Paynomys macronyx is the type species of the genus. Two subspecies recognized.

Subspecies and Distribution.

P.m.macronyxThomas,1894—highAndesinWCArgentina(MendozaandNNeuquénprovinces)andadjacentChile.

P.m. vestitus Thomas, 1903 — mediumto low-elevation localities in S Argentina (Neuquén, Rio Negro, Chubut, and Santa Cruz provinces) and adjacent Chile (Aysén and Magallanes regions).

Descriptive notes. Head-body 109-146 mm, tail 47-65 mm, ear 15-17 mm, hindfoot 25-27 mm; weight 46-96 g. Males and females are about equal in body size. The Andean Long-clawed Mouse is medium-sized, robust and vole-like, with relatively short rounded ears and tail; claws on forefeet are long (c.6-7 mm); furis thick and short, dark olive brown to dark coffee dorsally and buffy brown to grayish or whitish ventrally. Ventral color often extends onto sides and is sharply demarcated from dorsum in most individuals. Chromosomal complement of individuals from south-western Mendoza is 2n = 54, FN = 62.

Habitat. Mostly restricted to high Andean prairies, Nothofagus (Nothofagaceae) forests, and ecotonal areas. Some scattered,isolated populations of Andean Long-clawed Mice occur through central arid Patagonia in suitable wet and dense-covered grasslands or shrublands. In north-western Andean Patagonia, they live primarily in lenga forest ( Nothofagus pumilio) from timber line, where lenga is compressed by snow into chaparral, to edge of precordilleran steppe where it occurs in moist habitats or under shrubs, sometimes several kilometers from the nearest lenga tree.

Food and Feeding. Stomachs of trapped Andean Long-clawed Mice contained arthropods, green plant material, and considerable quantities of fungi. Individuals trapped in Bariloche ingested parts of at least 15 taxa of fungi. Fecal pellets collected from live-trap captures in shrubland environments of the steppe-forest ecotone of Argentinean Patagonia during reproductive period had c.60% arthropod remains. Captive individuals survived well on apples and rolled oats but also ate lucanid beetle larvae, ground beef,leaf bases of young amancay lilies (but not the succulent taproot), bamboo shoots, dandelion flowers, and various fungi including Cyttaria (Cyttariaceae) .

Breeding. Breeding season seems to begin abruptly when ground is still covered by snow (late winter) and continues in spring and summer (March). Neither males nor females were breeding in autumn. Individuals of both sexes may begin breeding before reaching full adult size. Mature testes are 11-14 mm long, and vesicular glands are 10 mm or more. Number of recorded embryos from trapped individuals was 4-5. There seem to be two age groups in autumn, probably young-of-the-year and adults slightly over a year of age. In spring. the population is primarily (or entirely) individuals born in the preceding spring or summer. Individuals born at the beginning of the reproductive season do not venture from their burrows until late spring.

Activity patterns. The Andean Long-clawed Mouse is primarily nocturnal and partly diurnal.

Movements, Home range and Social organization. Andean Long-clawed Mice are primarily subterranean; in winter, they construct networks of tunnels under snow; such networks may cover almost one-third of the surface over an area of 10-30 m?. Averaged lineal distance moved was 32 m. When several individuals are put together in a cage, they spar and jump about excitedly. Males and females make grating and squeaking sounds. In a mixed Araucaria araucana (Araucariaceae) -Nothofagus forest in Lanin National Park in south-western Neuquén Province, Argentina, remains of Andean Long-clawed Mice were discovered in a burrow of Brown Rat ( Rattus norvegicus), suggesting a potential impact of alien species on this native sigmodontine.

Status and Conservation. Classified as Least Concern on The IUCN Red List (as Chelemys Macronyx).

Bibliography. Alarcon et al. (2011), Candn et al. (2014), Chebez et al. (2014), D'Elia, Pardinas, Patterson &Teta (2016), Kelt (1994, 1996), Mann (1978), Mella (2006), Ojeda et al. (2005), Osgood (1925, 1943a), Pearson (1983, 1984, 1995), Pearson & Lagiglia (1992), Perez et al. (1989), Polop et al. (2015), Rau et al. (1978), Reig (1987), Reise & Venegas (1987), Shepherd & Ditgen (2012), Teta (2013), Teta, Canén et al. (2017), Teta, Pardinas & D'Elia (2015a), Thomas (1894, 1903b, 1916d, 1927c¢).