Uromys caudimaculatus caudimaculatus

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 : 152-153

Uromys caudimaculatus caudimaculatus

(Krefft, 1867)

Synonyms. Mus macropus (Gray, 1866) (not of Waterhouse); Uromys aruensis Gray, 1873 ; Uromys validus Peters & Doria, 1881 ; Uromys exilis Troughton & Le Soeuf, 1929 ; Uromys sherrini Thomas, 1923 .

Revised diagnosis. Distinguished from other subspecies as follows: i) hindfoot short, 18-22% of head and body length; ii) size large (condylobasal length of adults 63-72 mm); iii) fur colour "rabbity" grey brown or tawny, with underparts yellow or white; iv) feet white with a distinct brown line or block above; v) tail long, with only slight mottling in transition zone; vi) scales arranged in clear rings; frontal region of skull convex; vii) bullae somewhat flattened.

Discussion. There is more regional variation within U. c. caudimaculatus than in any other subspecies. Indeed, some of the more distinct regional forms have previously been recognised as subspecies. Individuals from the Aru Islands are smaller than those from elsewhere, and differ morphologically in possessing a distinct dorsal stripe. Those from the trans-Fly plains are again a little smaller than individuals from Australia, possess an indistinct dorsal stripe, have slightly less of the tail white, and have less warm tones in the fur. The Australian sample is, in contrast, remarkably morphologically homogeneous throughout its range. Baverstock et al. (1982), however, recognised two chromosome races within it: the southern race is characterised by the possession of two to 12 B chromosomes while the northern race lacks B chromosomes but possesses large blocks of distal C-positive heterochromatin on between 18 and 28 of the 46 chromosomes. Although these two chromosome races seem to be isolated from one another, and no chromosome intermediates are known, we could detect no differences based upon morphology or morphometrics to support the division of the Australian sample into two taxa.

Distribution. This subspecies is distributed from north-east Queensland throughout the trans-Fly plains to the Gulf of Papua and the Aru Islands.