Rattus nikenii

683.

Gag Island Rat

Rattus nikenii

French: Rat de Niken / German: Insel-Gag-Ratte / Spanish: Rata de Gag

Other common names: Niken's Rat

Taxonomy. Rattus nikenii Maryanto et al., 2010,

“Gag Island,

West Papua, Indonesia.”

Rattus nikenai is in the Recent New Guinea clade within Rattus. Populations of R. nikenii were previously allocated to R.praetor. Monotypic.

Distribution. Gag I, Indonesia; and perhaps other islands in the region.

Descriptive notes. Head-body 135- 300 mm, tail 138-165 mm, hindfoot 31-36-5 mm; weight 113-175 g. The Gag Island Rat is mediumto large-sized and similar to the Large New Guinea Spiny Rat (R. praetor), although it is considerably smaller on average, with shorter snout and hindfeet proportionately. Pelage is harsh and spiny. Dorsum is ashy gray, with light brown sides sharply demarcated from venter. Venter is white on chin, rufous merging to tawny on throat, brown to patchy light brown on chest, creamy on abdomen, and pale brown mixed with cream in scrotal area. Feet are grayish white dorsally. Ears are small, rounded, and similarly in color to dorsum; vibrissae are long. Tail is less than 100% of head-body length and unicolored blackish brown. Skull has oval profiled cranium and is altogether similar to Stein’s New Guinea Rat (R. stein). There are four pairs of mammae: two axillary and two inguinal.

Habitat. Probably ultrabasic, evergreen valley forests.

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 Vulnerable on The IUCN Red List. The GagIsland Rat was only recently recognized as a distinct species and has a very limited distribution (56 km?) that is completely in a protected area, although it is potentially threatened bynickel mining. More research is needed to fully understand its natural history, taxonomy, and conservation threats.

Bibliography. Engelbrektsson & Kennerley (2016a), Maryanto et al. (2010), Timm, Weijola et al. (2016).