The eastern Himalayas continue to reveal their biological secrets. Scientists have discovered a previously unknown species of venomous pit viper in the mountainous forests of Medog County in China’s Xizang Autonomous Region, resolving a long-standing case of mistaken identity along the way — specimens once assumed to belong to a widespread species turn out to represent an entirely distinct evolutionary lineage.

The genus Ovophis comprises medium-sized venomous snakes found across Asia, from Japan and southern China through the Indochina Peninsula to Nepal. For years, scientists assumed a single species, Ovophis monticola, occupied most of that vast range. But recent genetic studies have steadily chipped away at that assumption, revealing that what looked like one widespread snake is actually a complex of multiple distinct species — and in China’s Xizang region, historical records had conflated at least two different Ovophis species under a single name.

A New Species, Confirmed by DNA and Anatomy

A research team from the Chengdu Institute of Biology at the Chinese Academy of Sciences, together with collaborators from Jianghan University, China West Normal University, the University of Chinese Academy of Sciences, and Nepal’s Prithvi Narayan Campus, describe the new species — Ovophis medogensis — in the journal Asian Herpetological Research. It inhabits the tropical monsoon rainforests of Medog County at elevations between roughly 700 and 1,800 meters.

The new species can be distinguished from its closest relatives by a unique combination of traits: a distinctive dorsal scale pattern, 132 to 138 ventral scales, and 39 to 49 mostly paired subcaudal scales. Its coloration is equally telling — a dark brown back with irregular butterfly-shaped blotches, a brownish-orange stripe behind each eye, and an iris that flashes cream to orange-red with a single vertical black bar crossing the pupil. White spots run along the top of its tail all the way to the tip, a feature absent in its look-alike relatives.

Genetically, the divergence is just as clear. Mitochondrial cytochrome b sequences place the new species as the sister lineage to Ovophis monticola populations from Nepal and Nyalam County, with an uncorrected pairwise genetic distance of 5.5 percent — well above the threshold typically used to distinguish snake species. Phylogenetic analyses, supported by a Bayesian posterior probability of 1.00 and an ultrafast bootstrap value of 100, confirm its status as a distinct evolutionary unit.

“We kept finding these snakes in Medog and noticing they just didn’t look right” for the assumed species… “when we finally got the DNA data back, the differences were undeniable.” “The eastern Himalayas remain one of the least explored regions for reptile diversity.”

Study authors, Chengdu Institute of Biology

Why a New Snake Species Matters

The discovery brings the number of Ovophis species documented in Xizang to three, alongside O. monticola and O. zayuensis — though the researchers suspect the genus’s true diversity remains underestimated. Accurate species identification carries real practical weight for snakebite management in the region, since venom composition and effective antivenoms both depend on knowing exactly which species a patient encountered. With deforestation accelerating across South Asia’s lowlands, the authors stress that targeted surveys are urgently needed to map the new species’ full distribution and assess its conservation status.

The study was funded by the Second Qinghai-Xizang Plateau Scientific Expedition and Research (STEP) Program.

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The study was published in Asian Herpetological Research (DOI: 10.3724/ahr.2095-0357.2025.0067).