Trimeresurus tibetanus

The Tibetan pit viper, Trimeresurus tibetanus, is a venomous pit viper described by Huang in 1982, once listed as T. karanshahi. It has 21 rows of scales at midbody, 7 to 9 upper-lip scales and 145 to 159 belly scales, and is found at about 2,700 to 3,200m in forest, shrubland, grassland, rocky areas and cropland. Reports describe it both laying eggs and bearing live young (Wikipedia, general species account).

The source restricts it to the Tibet Autonomous Region of China and does not name Nepal, so its place on the Nepal list should be checked. It gives no size, diet, behaviour or venom detail (Wikipedia, general species account).