|The holotype of Azemiops kharini (ZISP 26028) from Tam Dao, Vinh Phuc Province, Vietnam.|
Fea’s viper, Azemiops fea was described by Boulenger in 1896, and assigned to its own subfamily in 1971. Its elliptically shaped, flattened head; enlarged head plates; smooth dorsal scales; folding front fangs; the absence of heat-sensing pits; and a coiled venom gland duct in adults all suggest Azemiops is a distinctive lineage of primitive vipers.
For many decades Azemiops fea was known from relatively few specimens, all had been collected in mountainous regions at altitudes up to 1000 m, with cool climates and they could be found in disturbed areas, including agricultural areas and secondary forests in southern China and north Vietnam. The monotypic species was known to feed on small mammals, with the only known specific prey – the common gray shrew (Crocidura attenuata).
Now, Orlov et al. (2013) have described Azemiops kharini, a second species of primitive viper from Tam Dao Mountain, Tam Dao Village, Vinh Phuc Province, Vietnam The new species, known as the white-head Burmese viper has a broader distribution than the blackhead Fea’s viper. The new species ranges from eastern China (eastern Yunnan, Guangxi, Guizhou, eastern Sichuan, Fujian, Zhejiang, Jiangxi, and Shaanxi provinces) and it is present in northern Indochina (northeastern Vietnam) The limited number of specimens probably under represents the distribution, but the two species of Azemiops are foundb a short distance from each other, and are apparently separated by the Red River Valley. Azemiops feae occurs west of the Red River, and Azemiops kharini occurs to the east of the Red River.
The white-head Burmese viper inhabits bamboo and tree-ferns thickets interchanged with open and lighted zones with deep leaf litter. Typical habitat is leaf litter near the trunks of fallen trees, with ferns and crevices in limestone rocks. Food is mostly rodents that are associated with swift, montane streams. It is active from the middle of May and lays clutches of five eggs.
Orlov NL, Ryabovn SA, Nguyen TT. 2013. On the Taxonomy and the Distribution of Snakes of the Genus Azemiops Boulenger, 1888: Description of a New Species. Russian Journal of Herpetology 20:110-128.