Draped in a uniform coat of vibrant grass-green and possessing eyes that shimmer like amber, a newly discovered pitviper is the latest hidden jewel to be found in the misty mountains of western Sichuan, China.
When researchers from the Chengdu Institute of Biology and the Giant Panda National Park began surveying the biodiversity-rich West China Rain Zone, they realised that what was once thought to be a common snake was actually an undocumented species. To honour the region's deep cultural roots and the spirit of the park where it resides, they named the snake Trimeresurus lii - the Huaxi Green Pitviper.
"The specific name lii honors Li Er, the ancient Chinese philosopher better known as Laozi," said the research team, led by Bo Cai. "His teachings emphasise the harmonious coexistence between humans and nature, a principle that perfectly aligns with the conservation mission of the Giant Panda National Park where this species was discovered."
The Huaxi Green Pitviper is the 58th species of the Trimeresurus genus identified worldwide and only the second of its specific subgenus to be found in Sichuan Province. For decades, these populations were mistaken for a more widely distributed relative, the bamboo pitviper T. stejnegeri, based on their similar green appearance. However, modern genetic testing and high-resolution morphological analysis revealed they were a distinct lineage.
When the team conducted the phylogenetic analysis of their DNA, the results demonstrated that this population formed its own distinct branch. Beyond the genetics, they also found consistent physical differences, such as their perfectly smooth head scales, which set them apart from their more common cousins.
The discovery, published in the open-access journal Zoosystematics and Evolution on January 30, describes a snake that is both elegant and highly specialised to its environment. While both sexes share a grassy green body color, they exhibit striking sexual dimorphism: males sport a tricolor stripe of red and white along their sides and possess amber eyes, whereas females have a simpler yellow stripe and orange-yellow eyes.
As a member of the Trimeresurus genus, it is also notable that the Huaxi Green Pitviper is a venomous species capable of causing snakebite envenoming. Because these snakes often share habitats with human settlements in mountainous regions, they pose a potential medical risk to local residents and visitors.
Growing up to nearly 80 centimetres in length, these pitvipers thrive in the humid forests of Mt. Emei and Xiling Snow Mountain. The region, known as the West China Rain Zone, is a global biodiversity hotspot where many species remain understudied.
The researchers believe this find is a reminder of how much remains to be discovered even in well-known areas. "This discovery highlights the importance of continued field surveys in biodiversity hotspots," the team stated.
