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Earless Water Mouse

Anotomys leander

French: Ichthyomys |éandre / German: Ohrlose \Wassermaus / Spanish: Ratén de agua de Ecuador

Other common names: Ecuador Fish-eating Rat, Ecuadoran Ichthyomyine

Taxonomy. Anotomys leander Thomas, 1906, “Mount Pichincha, Ecuador: mountain-streams at 11,500 feet [= 3505 m].”

Anotomys leander 1s the type species of the genus. Monotypic.

Distribution. Known from three Andean localities, one in W Colombia and two in NC Ecuador; an additional unconfirmed record exists from W Colombia.

Descriptive notes. Head-body 101-122 mm, tail 125-153 mm, hindfoot 34—

37 mm, ear (no pinnae are visible); weight 40-60 g. Dorsum of the Earless Water Mouse is woolly, dense, and dull gray or black, contrasting silvery white venter. Hairs of belly have dark gray bases. Tufts of pure white fur cover ear region. There are supraorbital vibrissae, and philtrum is absent. Hypothenar and third interdigital pads are fused showing only four plantar pads. Large hindfeet covered with dense fringe ofsilvery hairs are c.33% of head—body length. Plantar surface is blackish, hypothenar pad is absent, and claw offifth digit extends to base of claw on fourth digit. Brownish tail is longer than head-body length.

Habitat. Mossy elfin forest, grassy paramo, and shrubby ecotone at the forest edge at elevations of 2860-4000 m. In Colombia, the Earless Water Mouse inhabits streams with clear fast water in paramo and mossy dwarf forest.

Food and Feeding. The Earless Water Mouse eats small aquatic arthropods, mainly benthic insects and immature stages (larvae or nymphs).

Breeding. An Earless Water Mouse was recorded with a single large embryo in utero during late dry season in March.

Activity patterns. The Earless Water Mouse is semi-aquatic and probably nocturnal.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Vulnerable on The IUCN Red List. The Earless Water Mouse has a severely fragmented distribution and is found in less than 2000 km?.

Bibliography. Cuervo et al. (1986), Marin & Sanchez-Giraldo (2017), Thomas (1906b), Tirira & Boada (2010), Voss (1988, 2003, 2015b).