Kadarsanomys nov. gen. is proposed for Rattus sodyi Bartels, 1937, and contrasted with Rattus and Lenothrix, two genera with which sodyi has been closely connected in the past. Kadarsanomys sodyi is an arboreal rat associated with bamboo on the forested volcanoes of West Java. Kadarsanomys has no close relatives and is the only murid genus endemic to a single island on the Sunda Shelf. Kadarsanomys, Pithecheir and Lenothrix comprise the only endemic genera of Sundaic murids.