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Mirza’s Eastern Moss Rat

Mirzamys norahae

French: Mirzamys de Norah / German: Ostliche Moosratte / Spanish: Rata de musgo de Mirza oriental

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

“immediate vicinity of Porgera (05°28’S, 143°05’E, Enga Province, Papua New Guinea ...), 2650 m.”

Prior to description of genus Mirzamys in 2009, specimens of M. norahae were erroneously referred to Pseudohydromys occidentalis . Genus Mirzamys shows greatest morphological affinity to Paraleptomys . Monotypic.

Distribution. Known only from type locality in Enga Province, in C New Guinea.

Descriptive notes. Head-body 105-115 mm, tail 89-100 mm, ear 11-13-2 mm, hindfoot 22-22-4 mm; weight 30 g. Both known specimens are male. 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 that extend just 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 head-body length, 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 features of Mirza’s Eastern Moss Rat are its reddish-brown pelage, proportionally shorter tail (85-87% of head-body length), and proportionally shorter hindfeet and ears; additional distinguishing features in cranium.

Habitat. The habitat at type locality is mossy upper montane forest; above 2900-3000 m these forests give way to extensive subalpine tussock grasslands with open canopy of tree ferns ( Cyathea, Cyatheaceae). If this species parallels the better-known Mirza’s Western Moss Rat ( M. louiseae), it is likely to occur more widely within this regional mosaic of montane forests and subalpine grasslands.

Food and Feeding. The intestinal tract of one specimen (reported as Pseudohydromys occidentalis) contained spiders and various insects, including lepidopterans, but little, if any, plant or fungal material. Dietary focus on invertebrates is suggested also by the relatively short intestinal tract of Mirza’s Eastern Moss Rat compared with that of related species of Pseudohydromys .

Breeding. No information.

Activity patterns. No definite information.

Movements, Home range and Social organization. No information.

Status and Conservation. Not assessed on The [UCN Red List. The high-elevation habitats occupied by Mirza’s Eastern Moss Rat suffer little impact under traditional landuse patterns, but they are under potential impact from regional resource-development activities. The range of this murid is likely more extensive than is currently known.

Bibliography. Helgen (2007b), Helgen & Helgen (2009), Jackson & Woolley (1993), Musser & Carleton (1993, 2005), Richards (2007).