New Ireland forest rat

The New Ireland forest rat (Rattus sanila) is a large rodent in the family Muridae that is endemic to New Ireland, in the Bismarck Archipelago of Papua New Guinea. It was described by Flannery and White in 1991, with its type locality at Balof on New Ireland, and was first treated as a subspecies of Rattus mordax. Later comparison showed that its tooth measurements exceed those of even the largest known Rattus mordax, which supported treating it as a separate species, a status confirmed by analysis of rodent remains from New Ireland and Manus. Its upper molars are very complex compared with those of typical New Guinea Rattus, and one specialist suspects it may be a relict of an early dispersal of ancestral Rattus stock to New Guinea and Australia. The species is represented mainly by subfossil fragments dated to about 3000 years before present and older, from the late Pleistocene to the mid Holocene, but it may still live in primary forest, which has not been adequately sampled. The IUCN has not evaluated it.