329.

Bougainville Island Giant Rat

Solomys salebrosus

French: Solomys de Bougainville / German: Bougainville-Nacktschwanzratte / Spanish: Rata gigante de Bougainville

Other common names: Bougainville Giant Rat, Bougainville Island Solomys, Bougainville Naked-tailed Rat

Taxonomy. Solomys salebrosus Troughton, 1936,

Bougainville Island, Solomon Is-lands.

Solomys salebrosus is presumed to be the nearest relative of S. sapientis, but this remains to be confirmed by molecular studies. Phylogenetic study by IL. M. Bryant and colleagues in 2011 revealed S. salebrosus and S. ponceleti as sister-species. According to local inhabitants, islands of Makira and New Georgia have native rats similar to Solomys,these not yet scientifically described. Monotypic.

Distribution. Bougainville I and ChoiseulI. Fossils are known from Buka I.

Descriptive notes. Head—body 225-328 mm, tail 238-250 mm, ear 18:5-20 mm, hindfoot 47-50 mm; weight 290-460 g. The Bougainville Island Giant Rat is smaller than Poncelet’s Giant Rat ( S. ponceleti), and about the size of the Isabel Island Giant Rat ( S. sapientis). It differs from both in its peppered brown back and long guard hairs. It is similar in morphology to the Isabel Island Giant Rat, but has shorter hindfeet and less reddish back;it also has a coarser pelage, and different cranial features and heavier molars. Upperparts are yellowish brown, cinnamon buff on sides, and underparts are pinkish buff. Tail is naked, and similar to that of other Solomys . Females have four mammae.

Habitat. Bougainville Island Giant Rats prefer areas where tall stands of Pandanus (Pandanaceae) plants and figs ( Ficus, Moraceae) are abundant. On Choiseul this species is more commonly encountered in lowland rainforests; most records were made on village/forest interface in southern Choiseul. In 2012, local inhabitants on Choiseul reported seeing this rat while clearing vegetation for garden on the opposite side of the Kolombangara River.

Food and Feeding. Diet is composed of vines,fruits, figs, nuts, and edible leaves.

Breeding. Females may give birth to a single young. One young weighed 69 gand another 220 g. An individual of this species was encountered in a nest of leaves placed some 15 m above ground in a hollow of a large tree; two others were caught at different times in leaf nests made on a branch.

Activity patterns. Bougainville Island Giant Rats appear to be nocturnal and strictly arboreal. They nest mainly in trees of large girth.

Movements, Home range and Social organization. No information.

Status and Conservation. Classified as Endangered on The IUCN Red List because of a serious population decline inferred from the extent of logging on Choiseul and the increasing degree of logging on Bougainville . It is likely that hunting pressure on this speciesis also increasing. The Bougainville Island Giant Rat is threatened by logging, especially the selective logging of large roosting trees; predation by cats may also be a problem, but this requires confirmation. There has been increased hunting pressure on Bougainville in recent years, but the Bougainville Island Giant Rat is probablystill present in large areas of forest that have not been logged.

Bibliography. Boseto & Pikacha (2016), Bryant et al. (2011), Flannery (1995a), Flannery & Wickler (1990), Lavery et al. (2016), Leary, Seri, Flannery, Wright, Hamilton, Helgen, Singadan, Menzies, Allison, James & Bonaccorso (2008), Musser & Carleton (2005), Pikacha (2008), Pikacha & Sirikolo (2009), Troughton (1936a).