Vang Vieng lance-headed pit viper

Protobothrops flavirostris can be differentiated from other species in the genus Protobothrops with characteristics such as 23–21–17 dorsal scale rows, all the scales being keeled, 215 ventral scales, 79 subcaudal scales, with all of them being paired, 7–8 supralabials, 10 infralabials, and a lack of a horn like protrusion on the supraocular. In terms of colouration, Protobothrops flavirostris is uniquely known for its yellow snout and tail; there are also three dull stripes on the head, and the body is brown to greyish brown with reddish brown cross-shaped blotches.

Protobothrops flavirostris is a species endemic to the Vang Viang district, Vientiane, Laos. It has been found at attitudes of 200–400 metres (660–1,310 ft). It is known from limestone caves and limestone karst valleys.

Protobothrops flavirostris seems to be nocturnal, as the holotype was found during the night, and it seems to inhabit caves during the day. It also seems to be specialized in climbing, as the observed individual was quite agile. The diet of this species is unknown, but it may feed on bats and bent-toed geckos in the region.