274.

Black-tailed Mosaic-tailed Rat

Melomys rufescens

French: Mélomys roux / German: Schwarzschwanz-Mosaikschwanzratte / Spanish: Rata de cola moteada y negra

Other common names: Black-tailed Melomys

Taxonomy. Uromys rufescens Alston, 1877,

“Duke-of-York Island, New Britain, and New Ireland.”

Melomys rufescens is a complex of forms originally described as subspecies, but there is no general agreement on which should stand or be recognized as species. G. H. H. Tate in 1951 recognized nine subspecies. In a 1996 revision based on morphology, J. I. Menzies recognized seven subspecies with some geographical integrity: rufescens (New Britain and New Ireland), calidior (southwestern lowlands), gracilis (highlands), hagen: (highlands), niviventer (Fly-Digoel

plains), stalker: (northern and south-eastern lowlands), and wisselensis (Wissel Lakes). T. E. Flannery in 1995 and many subsequent authors have recognized gracilis and dollmani as representing a distinct species. In a collection from the Bulolo Valley between 1200 m and 1400 m, most specimens had tail length shorter than head-body, but a few had longer tail (greater than 110%); despite the altitude, these are probably of lowland race stalker . More study is needed. Seven subspecies currently recognized.

Subspecies and Distribution.

M.r.rufescensAlston,1877—NewBritainandNewIrelandIs.

M.r.calidiorThomas,1911—lowlandsofSWNewGuinea.

M.r.gracilisThomas,1906—SescarpmentoftheCentralCordilleraofNewGuineafromMtBosaviEtotheOwenStanleyRange.

M.r.hageniTroughton,1937—mountainsofNewGuineafromCWestPapua(=IrianJaya])EtotheKratkeRange.

M.r.niviventerTate,1951—lowerDigulandFlyriverbasins,SCNewGuinea.

M.r.stalkeriThomas,1904—lowlandsofN&SENewGuinea.

M. r. wisselensis Menzies, 1996 — known only from the Wissel Lakes area ofW New Guinea. Known also from islands of Waigeo, Salawati, Yapen, Blup Blup, Karkar, and Sideia (off NW, N & SE New Guinea), but subspecies involved not identified.

Descriptive notes. Head-body 113-146 mm, tail 108-175 mm, ear 13-17 mm, hindfoot 25-5-29 mm; weight 37-102 g. The Black-tailed Mosaic-tailed Rat is a small rat with soft to woolly, often reddish, fur without spines, and with some pure white fur on belly. In highland forms, the while belly fur may be restricted to anterior and posterior parts, with gray-based fur between. Tail is uniformly dark, and the scales each subtend one tiny hair except at tip, which is scaleless and prehensile; tail may beslightly shorter or longer than head-body length, and is longest in highland form gracilis . Hindfeet are broad, with prominent plantar pads. Subspecies calidior is larger in most dimensions, mean head-body length 138 mm, tail equal to head-body length; subspecies stalker: generally darker in color, mean head-body length 136 mm, head-body/tail (98%); Subspecies wisselensis larger in most dimensions than calidior but has longertail (though not so long as in highland forms), ventral white fur restricted, mean headbody length 133 mm, head-body/ tail (95%).

Habitat. Characteristic of open country, such as forest in early stage of succession after cultivation. Rarely found in well-developed forest. In absence of introduced Rattus species, the Black-tailed Mosaic-tailed Rat may persist in gardens and even roost in thatched roofs ofvillage houses. Ranges from sea level to 3500 m.

Food and Feeding. No information.

Breeding. Reproduction may be seasonal. Mean litter size appears to be slightly less than two.

Activity patterns. All forms appear to be either scansorial or totally arboreal. Nests are made in tree holes or under crowns of Pandanus (Pandanaceae), or woven in tall grass or reeds, especially among Miscanthus (Poaceae) canes, one to several meters above ground level.

Movements, Home range and Social organization. Because this species’ preferred habitat is open vegetation rather than closed forest, and such vegetation is often anthropogenic in origin and transitory, its occurrence is largely dependent on human activity. Black-tailed Mosaic-tailed Rats first appear a few years after farmland is abandoned, and disappear when succession advances to forest.

Status and Conservation. Classified as Least Concern on The IUCN Red List. In 1968, W. Z. Lidicker and A. C. Ziegler reported that this species was “widespread in the Bulolo Valley and adapting to the steadily increasing encroachment of human activity.” Usually common.

Bibliography. Dwyer (1978, 1984), Flannery (1995b), Lidicker & Ziegler (1968), Menzies (1996), Tate (1951).