Rattus nativitatis Thomas 1888

Rattus nativitatis Thomas 1888, Proc. Zool. Soc. Lond., 1888: 533.

Type Locality: Christmas Isl (Australia).

Vernacular Names: Christmas Island Rat.

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, 1990 c).

Conservation: IUCN – Extinct.

Discussion: Rattus species group unresolved. For Thomas (1888 b), 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, 1949 a) . 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). Four hypotheses about phylogenetic position of R. nativitatis require testing: 1) it is most closely related to R. macleari, the other endemic on Christmas Isl; 2) it is not related to R. macleari but to other species of Rattus; 3) it is a member of Rattus but phylogenetically isolated from all other species; 4) it is not even a member of Rattus .