669.

Andean Swamp Rat

Neotomys ebriosus

French: Néotomys des Andes / German: Anden-Sumpfratte / Spanish: Rata de ciénaga de los Andes

Other common names: Red-nosed Neotomys

Taxonomy. Neotomys ebriosus Thomas, 1894, “Valley ofVitoc [Junin], East Central Peru.”

Neotomys ebriosus is the type species of the genus. Although the speciesis treated here as monotypic, a south-western form (vulturnus) is time to time used to distinguish populations ranging from north-western Argentina to southern Peru on the west side of Lake Titicaca. Monotypic.

Distribution. Highlands in C & S Peru, extreme N Chile, W Bolivia, and NW Argentina; probably also in S Ecuador.

Descriptive notes. Head-body 97-149 mm, tail 62-86 mm, ear 17-19 mm, hindfoot 21-26 mm; weight 63-69 g. The Andean Swamp Rat is robust and medium-sized sigmodontine, with large head, tail shorter than body length, and broad hindfoot with well-developed claws. Fur is long and fine, and ordinary hairs on back are c¢.12 mm long, overlapping fine long piles attaining 24 mm. Dorsum is grizzled grayish brown; long gray hairs with white tips project above dorsum. Muzzle has prominent patch of rich ocherous—source of the specific epithet—contrasting with duller face and head color. Venter is grayish white to gray, and tail is bicolored, brownish gray above and whitish below; ocherous patch is present at base oftail. Hands and feet have pale buffy metapodials and white digits, with tinge of cinnamon, and ears are nearly circular in outline and brownish. Mystacial vibrissae are numerous but short and somewhatrigid. Tail is thick, with conic appearance, and entirely covered with hair, brown above, buffy on sides, and dull whitish below. Broad upper incisors are grooved near outer edges.

Habitat. Altiplano grasslands and shrubby steppe at elevations of mostly 2500-4500 m. Andean Swamp Rats have been trapped most commonly in grasslands along streams with dense cover, among reeds on lake margins, and in marshes. In San Guillermo National Park, they are found in grasslands associated with highland wetlands, inhabiting tunnels formed across dense formations of Festuca scirpifolia ( Poaceae) and Juncus balticus ( Juncaceae). Chilean specimens were trapped along a small stream in dense cover (highly modified by grazing and periodic burning) where shrubs and grasses reached heights of ¢.3 m. The Andean Swamp Rat has been treated typically as a mammal of the Andean Altiplano, inhabiting elevations above 3000 m, but in southern parts of its distribution, it occurs in places outside limits of Puna and related highland systems down to elevations as low as 1950 m.

Food and Feeding. The Andean Swamp Rat is supposedly herbivorous, judging by prismatic condition of its molars, large cecum, and powerful masseteric musculature.

Breeding. Juvenile Andean Swamp Rats were captured in May and July. Males with small testes (4-8 mm) were recorded in July-September. A female caught in August carried no embryos; a pregnant female was caught in February.

Activity patterns. The Andean Swamp Rat is diurnal or nocturnal, with individuals at higher elevations more active during warmth of the day and those at lower elevations more nocturnal. The species is terrestrial and some authors have suggested that it has semi-aquatic habits. Field notes of one collector, E. Budin, stated “More orless aquatic, living on the banks of streams and marshes, and one was caught among reeds on a little islet in a lake.” O. Pearson in 1951 noted “all of these specimens were caught in grassy places, and most were near streams.” Nothing from morphology supports the hypothesis of a close association between the Andean Swamp Rat and water.

Movements, Home range and Social organization. No information.

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

Bibliography. Anderson (1997), Barquez (1983), Ferro & Barquez (2017), Hershkovitz (1955), Jayat, Ortiz, Gonzélez et al. (2011), Martinez et al. (2012), Ortiz & Jayat (2015), Pardifas & Ortiz (2001), Pardinas, Teta & Salazar-Bravo (2015a), Pearson (1951a), Pine et al. (1979), Sanborn (1947a), Thomas (1921g, 1926e), Vargas et al. (2016).