Yamdena mosaic-tailed rat

The Yamdena mosaic-tailed rat (Melomys cooperae) is a medium-sized rodent of the family Muridae, first described in 1995 from specimens found on Yamdena Island in Indonesia. No other examples of the species have been found, so very little is known about it, and the IUCN lists it as Data Deficient. Recorded weights range from 64.5 to 96.5 g, with a head and body length of 118 to 140 mm. The upper parts are cinnamon-brown with blackish reflections on the nose and forehead, the cheeks are white and there are blackish rings around the eyes. The underparts, the inner surfaces of the limbs and the backs of the legs are white, and the short ears are cinnamon in colour. The tail, at 140 to 170 mm, is longer than the head and body and is lavender-grey above and pale grey below. It is told apart from other members of the genus Melomys by a longer last upper molar and by a combination of a very long tail, a long incisive foramen and distinctive white cheeks.