Hydromys shawmayeri (Hinton, 1943) . Ann. Mag. Nat. Hist., ser. 11, 10:552.

TYPE LOCALITY: Papua New Guinea, SE Bismarck Range, Purari-Ramu Divide, Baiyanka, 6500 ft .

DISTRIBUTION: New Guinea; recorded only along Papuan Central Cordillera from Hagen Range in the west to Mt Kaindi area in the east (localities 1 -4 that were mapped as “ H. habbema " in Musser and Piik, 1982:156).

COMMENTS: Although identified as H. habbema, specimens from Papua New Guinea were noted to exhibit significant morphological differences from true habbema in Irian Jaya, not only in body size but also in certain cranial proportions (Mahoney, 1968; Musser and Piik, 1982; Tate, 1951). These and other contrasts support the hypothesis of an eastern ( shawmayeri) and a western ( habbema) species, a pattern that is common to other New Guinea murines ( Pseudohydromys murinus and P. occidentalis, for example). Mahoney (1968) discussed the problems associated with the original holotype of shawmayeri, which was described as a species of Baiyankamys .