766.

Karoko Hill Rat

Bunomys karokophilus

French: Bunomys des karokos / German: Karoko-Sulawesi-Bergratte / Spanish: Rata de colina de Karoko

Other common names: Karoko Bunomys

Taxonomy. Bunomys karokophilus Musser, 2014,

“tropical lowland evergreen rain forest along the Sungai Sadaunta (01°23’S, 119°58’E), a tributary on right side of the Sungai Miu, at 3300 ft [= 1007 m].”

Bunomys karokophilus is in the B. fratrorum species group within Bunomys and is sister to B. fratrorum . Monotypic.

Distribution. WC mountain block of C Sulawesi (perhaps more extensive).

Descriptive notes. Head-body 150- 190 mm, tail 135-205 mm, ear 22-25 mm, hindfoot 36-44 mm; weight 95-175 g. The Karoko Hill Rat is medium-sized, with long, smooth, and soft pelage and shortish black guard hairs. Dorsum is dark gray or (usually) steel bluish gray, speckled with pale to very pale buff and gray underfur. Sides are paler, and nose, lips, and lower one-half of muzzle are white, but sides are gray. Venteris grayish white (whiter around throat, chest, and inguinal region) or (more commonly) dark gray or bluish gray, lightly speckled with white that does not contrast very much with dorsum. Juveniles have denser, woollier fur that is dark gray with flat tone and dark grayish white underparts. Feet are dark gray to brownish gray dorsally, with silvery highlights, being gray ventrally and having white digits. Claws are unpigmented. Ears are rubbery and sparsely covered in short hairs and range from shiny dark gray through bluish gray and grayish black. Tail is ¢.95% of head—body length and varies in color pattern individually, always with white distal part, while being glossy dark grayish brown to brownish gray dorsally and ranging greatly from slightly paler than dorsal pelage to glossy white ventrally, sometimes with speckling. Skull is stocky, generally small compared with other species of Bunomys, with short and wide rostrum. The fleas Sigmactenus alticola pilosus and Stivalius franciscae have been recorded on the Karoko Hill Rat. There are two pairs of inguinal mammae. Chromosomal complementis 2n = 42, FN = 60.

Habitat. Stream sides in lowland tropical evergreen rain forest at elevations of 823— 1150 m.

Food and Feeding. The Karoko Hill Ratis largely microphagous, feeding primarily on a single kind of ear fungus (of which it is named) but also invertebrates, vertebrates, and fruits. The ear fungus Awuricularia delicate, known as “karoko,” is the primary food eaten by the Karoko Hill Rat; it grows on wet, decaying tree trunks and limbs lying on the ground. The fungus is such a prevalent part ofits diet that individuals gorge on it until they cannot swallow more; stomach samples often contain only karoko. A captive juvenile ate only karoko while ignoring all other foods. Fungi are held in forefeet, and each rubbery lobe is chewed; tougher upper skin is discarded or folded back while underside is eaten. Karoko Hill Rats only eat firm, rubbery lobes and ignore those that are on the verge of being jelly-like masses. Gelatinous insides are also eaten. Unlike many other predatory Bunomys, Karoko Hill Rats are not aggressive eaters, generally being clumsy at eating earthworms, frogs, and invertebrates, probably because they are not large proportions of their diets. Only cicadids were eaten by captive individuals, and stomach analyses showed that they rarely consumed ants, centipedes, and orthopterans. A frog given to a captive Karoko Hill Rat was eaten halfway after the head was bitten. Some figs and unidentified fruits were also found in stomachs. The fig Ficus minahassae (Moraceae) was eaten by a captive individual.

Breeding. No information.

Activity patterns. The Karoko Hill Rat is nocturnal and terrestrial. A captive individual nested in a pile of leaves created in a depression dug in the soil in its cage. Nests in the wild are probably made in burrows like other species of Bunomys . Grooming was done by licking palms and variously wiping down nose and muzzle, behind ears over eyes and to nose;sides of body were licked near thighs, back, rump, inguinal area, and genitals.

Movements, Home range and Social organization. No information.

Status and Conservation. Not assessed on The IUCN Red List. The Karoko Hill Rat has a relatively small distribution and might be threatened by habitat destruction from logging and agricultural expansion.

Bibliography. Musser (2014).