Daovantien's limestone rat

Daovantien's limestone rat (Tonkinomys daovantieni) is a rodent of the family Muridae native to northeastern Vietnam, and the only known species in the genus Tonkinomys. It was first discovered in a forested talus habitat in the Huu Lien Nature Reserve, Lang Son Province. The animal has semispinous, dense, grayish black fur on the upperparts, a dark gray belly, gray ears, a thick bicolored tail that is considerably shorter than the head and body, and large, extremely bulbous footpads. Its body size, build and some skull features resemble those of Leopoldamys neilli from Thailand, while other skull features and the molar pattern recall species of Niviventer, Chiromyscus and Saxatilomys. It is petricolous, meaning rock-dwelling, and was found only in talus made of large limestone blocks; its distribution in the reserve is thought to be patchy. The Mammal Diversity Database records it as described in 2006 and places it in the tribe Rattini.