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Mirza’s Western Moss Rat

Mirzamys louiseae

French: Mirzamys de Louise / German: Westliche Moosratte / Spanish: Rata de musgo de Mirza occidental

Taxonomy. Mirzamys louiseae K. M. Helgen & L. E. Helgen, 2009,

“Star Mountains, Western District, Territory of Papua (Western Province, Papua New Guinea), at 10,500 ft (= 3180 m).” Prior to description of genus Mirzamys in 2009, specimens of M. louiseae were erroneously referred to Pseudohydromys occidentalis . Genus Mirzamys shows greatest morphological affinity to Paraleptomys . Monotypic.

Distribution. Known only from seven localities in Central Cordillera of New Guinea, including Star (= Jayawijaya) Mts and the Hindenburg, Victor Emanuel, and Blucher ranges. A subfossil specimen from an owl pellet deposit at 3450 m on Mt Jaya, W New Guinea, may also represent this species; if confirmed, this would extend both the geographic and elevational range of Mirza’s Western Moss Rat.

Descriptive notes. Head—body 95-120 mm, tail 100-124 mm, ear 14-16 mm, hindfoot 23-25 mm; weight 25-6 g (subadult female). Species of Mirzamys are small murines with soft, dense fur that is dark gray with dark brown wash on upperparts, and only slightly paler below; head with reduced eyes, moderately large dark ears,fine vibrissae extendingjust past ears; fur on head plain, lacking eye-rings and cheek patches; all feet with dark fur on upper surfaces, pigmented plantar surfaces, hindfeet elongate with claws on all digits and small plantar pads;tail approximately equal to combined length of head and body, finely scaled and thinly furred, entirely dark to tip. Dentition characterized by loss of third molars, basined molar morphology, and pale yellow-orange to ivory-colored enamel on incisors. Distinguishing external features of Mirza’s Western

Moss Rat are its dark brown pelage,tail equal to head—body length, and proportionally larger hindfeet and ears; additional distinguishing features in cranium. Mammae two on each side, both inguinal.

Habitat. Capture records across the geographic and elevational range of Mirza’s Western Moss Rat come from lower to upper montane forests, grading into the interface between forest and subalpine scrub and grasslands,at elevations of 1900-3200 m.

Food and Feeding. No information.

Breeding..ow mammary formula (two pairs) indicates small litter size.

Activity patterns. No information.

Movements, Home range and Social organization. No information.

Status and Conservation. Not assessed on The IUCN Red List. The number of examples of this species in collections indicates moderately high local abundance within preferred habitat. The high-elevation habitats occupied by Mirza’s Western Moss Rat suffer little impact under traditional land use, but they are under potential impact from regional resource-development activities.

Bibliography. Flannery (1995b), Flannery & Seri (1990), Helgen & Helgen (2009), Musser & Carleton (2005).