Groundbreaking Discovery of Rare Keelback Snakes in Northeast India

In a remarkable advancement for Indian herpetology, researchers from the Wildlife Institute of India (WII) have documented two rare snake species for the first time within India's borders. The Kachin Hills keelback (Hebius gilhodesi) and the Rakhine keelback (Herpetoreas davidi), both previously known exclusively from neighboring Myanmar, have now been confirmed in protected areas of Arunachal Pradesh and Mizoram. This discovery, published on 26 March 2026 in the Journal of Threatened Taxa, not only extends their known ranges but also underscores the untapped biodiversity potential of Northeast India's forests.

These non-venomous, semi-aquatic natricine snakes belong to the Colubridae family, characterized by their distinctive keeled dorsal scales—a raised ridge down the center of each scale that provides camouflage and traction in wetland environments. The findings highlight how molecular tools and meticulous fieldwork are revealing hidden reptile diversity in one of the world's richest biodiversity hotspots: the Indo-Burma region.

The Research Team Behind the Breakthrough

Leading the study were Sourav Dutta and Bitupan Boruah, researchers at WII's Chandrabani campus in Dehradun, Uttarakhand, under the guidance of Scientist E Abhijit Das. WII, an autonomous institution of the Ministry of Environment, Forest and Climate Change, is renowned for its postgraduate programs in wildlife science and ecology, training the next generation of conservation biologists. Das, with over 1,900 citations on Google Scholar, specializes in amphibian and reptile taxonomy, making him a pivotal figure in Northeast India's herpetological surveys.

Fieldwork spanned 2021 to 2023 across Arunachal Pradesh, Meghalaya, and Mizoram. During nocturnal surveys between 7 pm and 10 pm, the team encountered snakes in forest streams that didn't match known Indian species. This prompted genetic sequencing of the mitochondrial cytochrome-b gene and detailed morphological comparisons, confirming the identities.

Scientific Methods: Blending Genetics and Morphology

The identification process exemplifies modern taxonomy. Mitochondrial DNA (mtDNA) analysis provided genetic confirmation, while morphological exams included scale counts, hemipenial structure (for H. gilhodesi, described in detail for the first time), and coloration patterns. For H. gilhodesi, the range extended 107 km northwest; for H. davidi, an impressive 577 km.

• Genetic Step 1: Tissue samples extracted for cytochrome-b sequencing.
• Morphological Step 2: Measurements of snout-vent length, tail length, dorsal scale rows.
• Comparative Step 3: Matched against Myanmar holotypes and congeners.

This integrated approach is standard in WII's research, fostering skills vital for M.Sc. and Ph.D. students in wildlife forensics and systematics.

Profiling the Kachin Hills Keelback (Hebius gilhodesi)

Found in Namdapha National Park and Kamlang Tiger Reserve, Arunachal Pradesh, this nocturnal snake thrives in tropical evergreen and semi-evergreen forests. It measures around 40-50 cm, with olive-brown dorsum, black-edged scales, and a yellowish venter. Its hemipenis features a bifurcated tip with spines, aiding species differentiation. Preferring fern-covered floors and dense undergrowth near streams, it preys on small frogs and invertebrates.

The original research paper provides scale row formulas (19-19-17 dorsal rows) and genetic divergences of 2-4% from Myanmar populations, confirming subspecific consistency.

Profiling the Rakhine Keelback (Herpetoreas davidi)

Documented in Ngengpui Wildlife Sanctuary, Mizoram, amid leaf litter in lowland evergreen forests. Slightly larger at 50-60 cm, it displays a uniform brown body with subtle vertebral stripes and keeled scales enhancing grip on slippery substrates. Diurnal tendencies contrast its congener, hunting earthworms and aquatic insects near watercourses.

This species' dramatic range extension suggests gene flow across the Indo-Myanmar border, urging updated distribution maps for conservation.

Habitats: Streams and Forests of Northeast India

Both species inhabit riparian zones in protected areas. Namdapha, a UNESCO World Heritage contender, spans 1,985 sq km with elevations from 200-4,571 m, hosting 60+ mammal species. Ngengpui, in Mizoram's Lawngtlai district, preserves 11,635 hectares of pristine forest. These microhabitats—shaded streams with rocky beds—face threats from hydropower and logging, making such discoveries timely for protected area management.

Northeast India: An Indo-Burma Biodiversity Hotspot

Spanning eight states, Northeast India bridges the Indian subcontinent and Southeast Asia, boasting 7-8% of global bird species and high reptile endemism. Over 200 snake species occur here, with 20+ new records since 2010. The Indo-Burma hotspot, home to 13,000 vascular plants, loses habitat at 1-2% annually. WII's surveys contribute to India's National Biodiversity Action Plan, emphasizing academic-led monitoring.

• Arunachal: 64% forest cover, tiger reserves key for herps.
• Mizoram: 85% forested, community reserves vital.

Conservation Implications and Threats

Though non-venomous, these snakes indicate ecosystem health. Threats include habitat fragmentation, climate-induced stream alterations, and illegal wildlife trade. No IUCN status yet, but range extensions warrant Data Deficient listing. Recommendations: Enhanced patrols in reserves, community herp education, and genomic databases. WII's role in training forest officers via its MSc Wildlife Science program amplifies impact.

Wildlife Institute of India advocates integrating such findings into Schedule I protections under Wildlife Protection Act, 1972.

The Role of Academic Research in Herpetology

WII's herpetology lab exemplifies higher education's conservation pivot. With PhD programs in ecology, it produces experts like Das (author of A Naturalist's Guide to Reptiles of India). Student-led surveys build capacity; Boruah and Dutta's work highlights interdisciplinary training in genetics and fieldwork. India's 1,200+ herp species demand such efforts amid 200+ threatened.

Photo by Robert Bonnifet on Unsplash

Future Outlook: More Discoveries Await

With genomic tools and camera traps, Northeast could yield 10-20 new snake records/decade. Collaborative Indo-Myanmar surveys and AI species ID promise acceleration. For aspiring researchers, WII fellowships and ongoing media coverage spotlight opportunities. Protecting these 'hidden gems' ensures ecological balance.