Hydromys shawmayeri Hinton 1943

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 (1980 m).

Vernacular Names: Shaw Mayer's Water Rat.

Distribution: New Guinea; recorded only along the Papua New Guinea 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).

Conservation: IUCN – Lower Risk (nt).

Discussion: Although identified as H. habbema, specimens from Papua New Guinea were noted to exhibit significant morphological differences from true H. habbema in Prov. of Papua (= 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 eastern ( H. shawmayeri) and western ( H. habbema) montane species, a pattern that is not uncommon to other New Guinea murines (e. g., Pseudohydromys murinus and P. occidentalis). Mahoney (1968) discussed the problems associated with the original holotype of shawmayeri, which was described as a species of Baiyankamys . Reviewed by Flannery (1995 a).