Pseudohydromys fuscus

307.

Mottled-tailed Shrew Mouse

Pseudohydromys fuscus

French: Souris-musaraigne a queue tachetée / German: Fleckenschwanz-Moosmaus / Spanish: Raton musarana de cola moteada

Taxonomy. Neohydromys fuscus Laurie 1952,

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“High northern slopes Mt. Wilhelm, Bismarck Range, NE. New [Papua] Guinea, 9000-10,000 feet [= 2743-3048 m].”

Pseudohydromys fuscus was originally described as a new genus and species and maintained as such until 2009, when K. M. Helgen and L. E.Helgen argued for a more inclusive definition of Pseudohydromys. Helgen and Helgen regarded P. fuscus as a highly distinctive species, with no close relatives among congeners. In the Hagen and Bismarck Ranges it issyntopic between 2400 m and 2800 m with P. murinus, P. eleanorae, and P. ellermani. Monotypic.

Distribution. Widely distributed in E half of the Central Range of New Guinea.

Descriptive notes. Head-body 80-110 mm, tail 72-90 mm, ear 11-14 mm, hindfoot 20-25 mm; weight 14-2-25-5 g. Pseudohydromys is a taxonomically diverse group of smallbodied murines characterized by dense, velvety to plush fur; a variably narrowed and flattened head with small eyes and ears; head generally without contrasting pattern; vibrissae fine and elongate, extending past ears; eyes small to minute; narrow hindfeet, lacking webbing between digits and with claws on all digits;tail narrow and thinly furred, approximating to combined length of head and body; mammae (when known) two on each side, both inguinal; cranium delicately built, with small molars reduced in number to two or fewer per quadrant. The Mottled-tailed Shrew Mouse is a medium-sized member of the genus;fur is short and velvety, uniform gray on upperparts or with pale flecking on back and rump,slightly paler below, with no contrasting markings on head; vibrissae extending well past ears; eyesless reduced that in most congeners; ears small and pale gray; upper surfaces of feet white; tail proportionally shortest in genus, averaging 84% of head-body length, pale for most of length, often mottled, and usually with white tip up to one-third of tail length. Mammae two on each side, both inguinal. Cranium relatively broad and robust, with broad, forward-projecting upper incisors; upper and lower incisors with red enamel; molars two per quadrant but very reduced. Phallic morphology suggests possible relationship with ellermani species group. Spermatozoa with head 9 pm long and 3 pm wide, with apical hook and two accessory paired ventral hooks.

Habitat. All captures have been made in evergreen tropical montane rainforest, including both lower and upper montane rainforests, from 1600 m to near limit oftree growth at 3660 m on Mount Wilhelm.

Food and Feeding. A study of the diet of the Mottled-tailed Shrew Mouse and those of two congeners in Morobe Province, as reflected by gut contents, found this species to be primarily insectivorous, eating more lepidopterans and fewer beetle and oligochaete worms than did Shaw Mayer’s Shrew Mouse (P. ellermani) and the Eastern New Guinea Shrew Mouse (P. murinus).

Breeding. The low mammary formula (two pairs) indicates a small littersize.

Activity patterns. No information.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The lower part of the elevational range in the central cordillera of Papua New Guinea coincides with a zone of extensive habitat modification owing to long-term subsistence agricultural activities. Habitats above 2500 m are much less affected by subsistence activities, but, in places within theMottled—tailed Shrew Mouse’s range, are potentially impacted by large-scale resource-development projects.

Bibliography. Aplin (2016u), Breed & Aplin (1995), Flannery (1995b), Helgen & Helgen (2009), Jackson & Woolley (1993), Laurie (1952), Lidicker (1968), Menzies & Dennis (1979), Musser & Carleton (1993, 2005).