Uromys hadrourus (Winter, 1984)

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 : 154

Uromys hadrourus (Winter, 1984)

Synonyms. Melomys hadrourus Winter, 1984 .

Type material. HOLOTYPE, QM J504 , adult female, skin and torso in spirit, skull extracted, collected near the summit of Thomton Peak (1,220 m, 16°09'30"S 145°21'45"E) on 16 Nov. 1973 by J. Winter.

Revised diagnosis. Uromys hadrourus differs from other species of Uromys as follows: i) smallest member of the genus; ii) white tail tip that lacks mottled interdigitation with dark proximal area of tail is unique; iii) the postorbital processes reduced; iv) braincase more inflated; v) anterolateral bullar spurs proportionally smaller.

It resembles U. caudimaculatus in its palate spine, palate form, rounded braincase, suppressed dentary tubercle, long incisive foramina (25% of palate length), small teeth, tail scales arranged in rings and longer than broad, and its general fawn colour and white feet with a marked brown dorsal line. It differs in its thinner preorbital bar, anteriorly angled lambdoidal suture, flattened interorbital region, less downwardly bowed zygomatic arches, reduced coronoid processes, lesser extent of white on the tail, broad feet, and restriction of white ventrally to the throat and chest.

Discnssion. Uromys hadrourus is thus far known from only five museum specimens, all collected at above 300 m on the Thornton Peak massif, north-eastern Queensland. This massif is isolated from other areas of upland rainforest by the Daintree and Bloomfield Rivers and sclerophyll forest.

Winter (1984) described U. hadrourus as a large species of Melomys . Although he discussed the possibility that it may represent a small species of Uromys , he discounted this on the basis of its small size, noting nonetheless that the well-developed tail and thickened upper incisors of U. hadrourus were striking similarities shared with the species of Uromys . Our cladistic analysis shows that U. hadrourus shares many derived features with the species of Uromys , but none with other mosaic-tailed rats. Such features include the posterior lengthening of the bony palate and the large anterolateral spur of the bulla which are synapomorphic for this genus. Phenetically, U. hadrourus is very close to other species of U. ( Uromys ) in skull shape, details of dental morphology and the thickness of the tail.

Uromys hadrourus is clearly a member of the U. caudimaculatus group of the subgenus Uromys , and even shares a few possibly derived features with U. c. caudimaculatus which are not seen in U. c. papuanus and U. c. multiplicatus : notably the white feet with a vaguely expressed brown longitudinal line on the upper surface. Other similarities are, however, plesiomorphic, and on balance it seems likely that it is the sister species to the entire species U. caudimaculatus .