706.

Yapen Island Rat

Rattus jobiensis

French: Rat de Yapen / German: Yapen-Ratte / Spanish: Rata de Yapen

Other common names: Japen Rat, Yapen Rat

Taxonomy. Rattus leucopus jobiensis Riimmler, 1935,

Pulau Yapen in Teluk Cendrawasih (= Geelvinck Bay), Province of Papua, West Papua (= Irian Jaya), Indonesia.

Relationship of R. jobiensis in Rattus is un-certain, but it probably is part of the Recent New Guinea radiation. It has been included in R. leucopus, although they are clearly distinct. Monotypic.

Distribution. Supiori, Biak, Owi, and Yapen Is, off NW New Guinea.

Descriptive notes. Head—body 212-252 mm, tail 186-227 mm, ear 22-3-23-3 mm, hindfoot 44-51 mm; weight 260-500 g. The Yapen Island Rat is large, with very coarse, long, and spiny pelage and spines and blackor tan-tipped guard hairs mixed throughout. Dorsum is grizzled medium to dark brown, with translucent spines and pale brown tipped hairs. Juvenile pelage is steel gray and less spiny. Dorsal pelage blends into ventral pelage. Vent is buff or dusky yellow white, with medium gray underfur and occasional rufous spot on chin and pectoral region. Feet are lightly covered with white to light buffy hair. Ears are sparsely covered with small brown hair; vibrissae are long. Tail is ¢.92% of head-body length, unicolored dark brown, and naked. Skull is elongated, withlong narrow rostrum. There are three (Yapen and Owi Islands) or four (Biak-Supiori Islands) pairs of mammae: one or two pectoral and two inguinal.

Habitat. Tropical moist forest, forest edge, rural gardens, and villages at elevations up to 600 m.

Food and Feeding. No information.

Breeding. A non-reproducing female Yapen Island Rat and ajuvenile male were found in September, suggesting reproductive season before September.

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 Yapen Island Rat has a rather restricted distribution and might be threatened by deforestation and competition with introduced Rood Rats ( R. rattus). More research is needed to fully understand its natural history, taxonomy, and threats.

Bibliography. Flannery (1995a), Leary, Singadan, Menzies, Wright, Aplin & Helgen (2008a), Musser & Carleton (2005), Taylor et al. (1982).