Ovophis zayuensis is a species of Asian pit viper. It occurs in Xizang (Tibet), Yunnan, northeastern India, and Myanmar. Ovophis are relatively large, broad-bodied pit vipers with pronounced sexual size dimorphism. They are widely distributed in mountainous regions throughout Asia. Ovophis monticola, the best known species, are terrestrial, nocturnal snakes that occur at moderate altitudes and favor moist conditions, feeding largely on rodents and reacting aggressively to disturbance. They reach sexual maturity at around 3 years of age and females lay 5–18 eggs and guard their clutch for around 2 months until hatching occurs. Leviton et al. (2003) describe Ovophis monticola as secretive and sluggish, often found hidden away in rock or log piles, and give the elevational range as 700–2400 m.
Investigations in recent years have revealed previously unrecognizerd complexity and important new insights with respect to the systematics of Asian pit vipers. For example, the species known as "Ovophis chaseni" (known only from the mountains of northern Borneo) is apparently not closely related to any other extant pit vipers and the species known as "Ovophis okinavensis" is apparently more closely related to Trimeresurus gracilis than to other Ovophis species--and T. gracilis is apparently not actually a part of the Trimeresurus radiation (Malhotra and Thorpe 2004 and refereces therein; Tsai et al. 2012 and references therein)!
Malhotra et al. (2011) undertook a broad phylogenetic analysis of Ovophis and concluded that the genus includes five very similar but diagnosable species:
O. makazayazaya (Taiwan, eastern and western China, northern Vietnam)
O. tonkinensis (southern China, northern and central Vietnam)
O. monticola (Nepal, northeastern India, Myanmar, northern Thailand, southern Laos, southwestern China [Sichuan and Yunnan], and northern and central Vietnam)
O. zayuensis (Xizang, Yunnan, northeastern India, and Myanmar)
O. convictus (West Malaysia)
(Malhotra et al. 2011 and references therein)
