320.

Vangunu Giant Rat

Uromys vika

French: Uromys de Vangunu / German: Vangunu-Riesenratte / Spanish: Rata gigante de Vangunu

Other common names: Masked White-tailed Rat, Masked White-tailed Uromys, Pygmy White-tailed Rat, Thornton Peak Melomys

Taxonomy. Uromys vika Lavery & Judge, 2017,

“Vangunu Island, Solomon Islands (8°43’14-16”S 157°55°34-44’E) at 145 m above sea level.”

Uromys wvika is in the subgenus Cyromys along with the three Guadalcanal species, U. rex, U. imperator, and U. porculus, although this has yet to be confirmed by genetic data. U. vika is the first species of Uromys in the Solomon Islands, apart from rats on Guadalcanal, to have been discovered alive, and there are further indications that other species of Uromys, Solomys, and Melomys are present throughout the rest of the island chain. Monotypic.

Distribution. Vangunu I, Solomon Is; possibly on other nearby Is.

Descriptive notes. There are no external measurements for this species; estimated weights are 290-460 g. Holotype, the only known specimen of the Vangunu Giant Rat, was a subadult that was not preserved well, and it mostly rotted except for some hair, skull, and partial skeleton. It is a relatively small species of Uromys . Pelage is shorter and less woolly than that of other Solomon Island species. Dorsum is cinnamonbrown, with individual hairs buffy at base, gray in middle, and cinnamon-brown attip, and dark guard hairs. Eyes are surrounded by a ring of sparsely furred skin. Venter is creamy white, fading from cinnamon-brown dorsum. Feet are broad, long, and brownish above and pinkish below, being sparsely furred dorsally. Claws are long and curved. Ears are small and pale brown; vibrissae are long, thick, and dark. Nearly hairless tail is probably longer than head-body length, although it was damaged during capture. Skull is very broad, with short maxillary tooth row and incisive foramina.

Habitat. Lowland tropical rainforest. The single specimen of the Vangunu Giant Rat was captured in a cut-down kapuchu tree ( Dillenia salomonensis, Dilleniaceae) at an elevation of 145 m.

Food and Feeding. Vangunu Giant Rats are reported to feed on coconuts and Canarium nuts, which have been found with whole gnawed through them. There are reports of an unidentified rat on Malatai that may represent this or a related species that cracks open rather than gnaws through the hard outer layer of Canarium nuts.

Breeding. No information.

Activity patterns. The Vangunu Giant Rat is probably nocturnal and arboreal. It is reported to build nests with epiphytes, but may also nest in tree hollows.

Movements, Home range and Social organization. No information.

Status and Conservation. Not assessed on The IUCN Red List. The Vangunu Giant Rat would probably be listed as Critically Endangered because of habitat destruction from logging, which is very prevalent on Vangunu Island. Additional research is needed in order to gain a full understanding ofits natural history, taxonomy, and conservation status.

Bibliography. Lavery & Judge (2017).