703.
Western New Guinea Mountain Rat
Rattus arrogans
French: Rat des Snow / German: Kleine Westneuguinea-Ratte / Spanish: Rata de montana de Nueva Guinea occidental
Taxonomy. Stenomys arrogans Thomas, 1922,
“Doormanpad-bivak, 2400 m,”
northern slopes Snow Mountains (Pegunungan Maoke), Province of Papua, New Guinea.
705.
Mount Giluwe Rat
Rattus giluwensis French: Rat du Giluwe / German: Giluwe-Ratte / Spanish: Rata de Giluwe Other common names: Giluwe Rat
Rattus arrogans has not been included in
any phylogenetic studies, and additional research is needed to understand its placement in Rattus. It was previously included in R. niobe but is recognized as a species until further research into the R. niobe species complex is conducted. Monotypic.
Taxonomy. Rattus ruber giluwensis Hill, 1960,
Mount Giluwe, 11,000-12,000 feet (= 3350— 3660 m), Papua, north-eastern New Guinea.
Rattus giluwensis is in the Recent New Guinea species group and sister to a clade including R. verecundus, R. praetor, R. steini, and R. novaeguineae. Monotypic.
Distribution. W New Guinea.
Descriptive notes. Head-body 130-6 mm, tail 113-6 mm, ear 17 mm, hindfoot 27-6 mm (averages). No specific data are available for body weight. The Western New Guinea Mountain Rat is very small and similar to but on average larger than the Eastern New Guinea Mountain Rat (R. niobe). Pelage is soft and without spines. Dorsum is dark graybrown, nearly black, and with rusty tipped hairs (darker than those on the Eastern New Guinea Mountain Rat). Dorsal pelage blends into ventral pelage. Venter is dark graybrown, with cream to rufous-tipped hairs. Feet are lightly covered in silvery and brown hairs dorsally. Ears are dark brown and relatively long; vibrissae are long. Tail is ¢.87% of head-body length and unicolored dark brown, with shorttail hair. Skull has broader interorbital region and long incisive foramen. There are three pairs of mammae: one pectoral and two inguinal pairs.
Habitat. Montane moss forest and alpine habitats at elevations of 2200-4100 m.
Food and Feeding. No information.
Breeding. No information.
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 Western New Guinea Mountain Rat has a large distribution and presumably large overall population and is found in multiple protected areas. Additional research is needed to fully understand its natural history and conservation threats.
Bibliography. Aplin (2016h), Flannery (1995b), Helgen (2007a), Laurie & Hill (1954), Musser & Carleton (2005), Taylor, Calaby & Smith (1990), Taylor, Calaby & Van Deusen (1982).
704.
Manus Island Spiny Rat
Rattus detentus
French: Rat de Manus / German: Manus-Ratte / Spanish: Rata espinosa de Manus
Other common names: Admiralties Rat
Taxonomy. Rattus detentus Timm et al., 2016,
“asmall stream near western end ofKawaliap Village, el. 200 m (2°6’40”S, 147°3’40”E), Manus Island, Admiralty Islands, Manus Province, Papua New Guinea.”
Rattus detentus 1s basal to all other species in the Recent New Guinea clade in Rattus. Monotypic.
Distribution. Manus I, Papua New Guinea (natives claim Los Negros Is).
Descriptive notes. Head-body 260 mm,
tail 150 mm, ear 23-4 mm, hindfoot 43-2 mm. No specific data are available for body weight. The Manus Island Spiny Rat is large and heavily built, with long, harsh, and spiny pelage. Dorsum is dark gray, heavily flecked with pale gray and many translucent spines, some with rufous or dark tips; prominent black guard hairs (longer on rump) are mixed throughout. Dorsal underfur is pale gray, and fur on outer parts of limbs is lighter. Rhinarium is white, and sides of rostrum have short dark hairs. Venter is white and lacks spines. Feet are white, with dark pigment speckling caused by short dark hairs thinly covering dorsal part. Claws are robust and ivory. Undersurface offeet has irregular gray patches. Ears are white at bases, grayer toward ends; vibrissae are fairly long and black. Tail is only ¢.58% of head-body length, dark gray throughout with paler mottling at very base, and covered with short bristly hair. Skull has elongated and anteriorly broadened rostrum, relatively short and bowed incisive foramina that terminate anterior to molar rows and short and uninflated auditory bullae. There are four pairs of mammae: one pectoral, one post-axillary, and two inguinal pairs.
Habitat. Mosaic of Metroxylon (sago) palms (Arecaceae) and mixed tapioca (Manihot esculenta, Euphorbiaceae), vegetable gardens, and secondary regrowth scrub from sea level to elevations of ¢.200 m.
Food and Feeding. The Manus Island Spiny Rat might feed on fallen nuts of Canarium indicum (Burseraceae), as indicated by conspicuous gnawing on nuts, but this might also be caused Pacific Rats (R. exulans).
Breeding. Holotype of the Manus Island Spiny Rat was carrying two fetuses, each 1 cm long.
Activity patterns. The Manus Island Spiny Rat might be nocturnal and terrestrial; it makes nests in burrows.
Movements, Home range and Social organization. No information.
Status and Conservation. Not assessed on The IUCN Red List. The Manus Island Spiny Rat seems to be rather rare and might compete with the Pacific Rat. Lowlands and coastal region of Manus Islands are largely deforested and replaced by plantations. The species is commonly hunted by natives for food. It is reported to be common by natives, although it seemsto be hardto capture, and populations might be decreasing. Additional research is needed to fully understand its natural history and conservation threats.
Bibliography. Timm, Weijola et al. (2016).
Distribution. Mt Giulwe and its nearby peaks and Kaijende Highlands, EC New Guinea.
Descriptive notes. Head-body 136— 187 mm, tail 84=108 mm, hindfoot 28— 32 mm; weight 50-60 g. The Mount Giluwe Rat is small and vole-like, with long, very thick, and soft pelage without spines. Dorsum is rich cinnamon brown, with longer
black guard hairs throughout, being more conspicuous toward rump. Juveniles are less richly cinnamon brown, with less developed guard hairs. Dorsal pelage fades into ventral pelage. Venter is yellowish gray, being dark or steel gray with yellowish buff to cinnamon tips. Feet are dark brown and covered with light brown hair dorsally. Ears are covered with short brown hair and are a similar color to dorsum; vibrissae are fairly short. Tail is only ¢.65% of head-body length and uniformly brown, with inconspicuous hairs throughout. Skull is thinly built, with small rostrum compared with cranial region. Gastrointestinal helminth genera Heterakis and Odilia have been found in Mount Giluwe Rats. There are four pairs of mammae: one pectoral, one postaxial, and two inguinal pairs.
Habitat. Subalpine grassland, moss forests, and beech-moss zone at elevations of 2195— 3660 m.
Food and Feeding. Diet probably consists of grass seeds and buds and flowers of alpine plants.
Breeding. Reproduction probably occurs in February-March, June, and October.
Activity patterns. The Mount Giluwe Rat is probably nocturnal. It constructs shallow tunnels that lead to nests in tussock grass.
Movements, Home range and Social organization. No information.
Status and Conservation. Classified as Least Concern on The IUCN Red List. The Mount Giluwe Rat has a restricted distribution but seems to have a stable overall population. It is preyed on by domestic dogs and might be threatened by increased fire frequency in the region.
Bibliography. Flannery (1995b), Helgen (2007b), Helgen & Opiang (2011), Gerrie & Kennerley (2016b), Musser & Carleton (2005), Smales (2016), Taylor et al. (1982), Timm, Weijola et al. (2016).