Uromys (Cyromys) imperator (Thomas, 1888)

Groves, C. P. & Flannery, Tim F., 1994, A revision of the genus Uromys Peters, 1867 (Muridae: Mammalia) with descriptions of two new species, Records of the Australian Museum 46 (2), pp. 145-169 : 149-150

Uromys (Cyromys) imperator (Thomas, 1888)

Type material. HOLOTYPE, BM 88.1 .5.33, adult female skin and skull collected at Aola, northern Guadakanal , Solomon Islands, by C.M. Woodford.

Revised diagnosis. Uromys (Cyromys) imperator is the largest of the species of Cyromys . The pads of the feet are reduced in size relative to other Cyromys , and the molars relatively much broader. It is similar externally to u. rex , with its dark grey, somewhat woolly fur (as aptly described by Thomas, 1888), grading to white below, and its very short ears. In comparison with U. rex , however, the head and body is longer, and the tail shorter with smaller scales (9-11 per cm versus 7-9 per cm). The skull is characterised by a median posterior palatal spine; very square posterior nasals which end comparatively far forward, anterior to a line connecting the posterior ends of the lachrymals; a relatively vertical ascending ramus with a low, rounded coronoid process; and a small dentary ridge and tubercle.

Discussion. Uromys imperator is still known with certainty only from the original three specimens collected by Charles Woodford at Aola on Guadalcanal in 1887. Woodford probably purchased the specimens from local hunters, and it is unlikely that they were collected far from the coast as Woodford (1890) mentions repeatedly the near impossibility of travelling far inland for fear of neighbouring tribes. A flat skin without a skull in the Australian Museum ( AM M19739 ) may, however, also represent this species. Its tail scales are less rasp-like than the Museum's specimens of U. rex , and the size is considerably larger, although smaller than the previously known specimens of U. imperator . It was collected by a Captain G. Hart. Other specimens collected by Captain Hart in the Museum Collections are from Lavoro Plantation in far northern Guadalcanal, and were collected in August 1933. On balance, we think this likely to be U. rex because of the larger foot pads, but the difficulty of identification reinforces our conclusion that the two species are extremely close.

Recently the remains of U. imperator have been found in archaeological deposits in northern Guadalcanal (Flannery & Roe, in preparation). Extensive questioning of the older people of Guadalcanal suggest that it may well be extinct, there having been few or no reliable sightings over the last 40 years, and also suggest that within living memory it was encountered only in montane mossy forest. This is surprising, considering that the archaeological deposits within which its remains have been found are now located in savannah areas near sea level, far distant from any mossy forest, and that Woodford's specimens probably came from near the coast.

Because of its short tail and reduced pads on the feet, Thomas (1888) considered this species to be terrestrial. This hypothesis is strengthened both by information related to one of us ( TFF) by older men who had seen it in their youth, and from an examination of the adult male in the Natural History Museum specimen ( BM 1888.1.5.32) which has considerable amounts of clay and earth adhering to the claws, forepaws and muzzle, suggesting that it was dug from a burrow.