Koopman's pencil-tailed tree mouse

Koopman's pencil-tailed tree mouse (Chiropodomys karlkoopmani) is a species of arboreal rodent in the family Muridae. It is endemic to the Pagai and Siberut islands in the Mentawai Islands, off the western coast of Sumatra in Indonesia. Its natural habitat is tropical primary lowland forest, and it is threatened by habitat loss caused by logging. The Mammal Diversity Database places it in the subfamily Murinae, tribe Hydromyini and genus Chiropodomys, in the Indomalaya biogeographic realm. The species was described in 1979 by G. G. Musser in a study of the arboreal mice of Indochina and the Malay Archipelago; its holotype was collected on North Pagai Island in primary forest on flat lowlands, probably near the coast. The IUCN Red List rates it Vulnerable.