Rattus nativitatis (Thomas, 1889)

Guy G. Musser & Michael D. Carleton, 1993, Order Rodentia - Family Muridae, Mammal Species of the World (2 nd Edition), Washington and London: Smithsonian Institution Press, pp. 501-755 : 656

Rattus nativitatis (Thomas, 1889) . Proc. Zool. Soc. Lond., 1888:533 [1889].

TYPE LOCALITY: Christmas Isl ( Australia) .

DISTRIBUTION: Endemic to Christmas Isl, 320 km south of Java in the Indian Ocean; suspected to be extinct by 1908 ( Andrews, 1909) and is now considered extinct ( Flannery, 1990c).

COMMENTS: For Thomas (1888b), the morphology of R. nativitatis distanced it from any other described species of Rattus . Ellerman (1941) first listed the species as the only member of the " nativitatis " group in subgenus Rattus , then placed it and R. macleari in same group within subgenus Stenomys of Rattus ( Ellerman, 1949a) . Chasen (1940) thought R. nativitatis to be without close relatives in Malaysia, but Misonne (1969) placed it close to rajah in the subgenus Leopoldamys of Rattus , an allocation rejected by Musser (1981 b) and Musser and Newcomb (1983). Three hypotheses about phylogenetic position of R. nativitatis require testing: 1. It is more closely related to R. macleari , the other endemic on Christmas Island than to any other species of Rattus ; 2. It is not related to R. macleari but to other species in the genus or is phylogenetically isolated; 3. It is not even a member of Rattus.