In a remarkable discovery, wildlife rescuers in Thane have documented the presence of a rare species of Bronzeback snake (Dendrelaphis cf proarchos), previously unknown from western India. The finding — confirmed by herpetologists — could significantly expand the known range of this slender, tree-dwelling snake. A recent study has shed new light on the distribution of Dendrelaphis proarchos, a species previously thought to dwell only in Northeast India.
“Earlier, its presence in western India was believed to be an isolated, human-mediated introduction. However, multiple individuals rescued by our NGO, Wildlife Welfare Association (WWA–India), along with verified photographic records from Gujarat, Mumbai, and Thane, strongly suggest a naturally occurring population in western peninsular India,” said Lalit Dnyaneshwar Ghadi. The research note, conducted by wildlife biologist Kushal Mohandas Vaishnav and Ghadi on behalf of WWA–India, was recently published in a scientific journal.
WWA had received rescue calls for this species on two separate occasions — one in July 2022 and another in April 2023. The first snake, rescued on July 22, 2022, from the Thane-Mulund area near Yeoor Hills of Sanjay Gandhi National Park (SGNP), was safely retrieved and documented. The second, rescued in April 2023 from an autorickshaw in Thane, further supported the possibility of a resident population.
Researchers also noted that a recent article on “atypical bronzebacks” published in 2021–2022 described two similar snakes, which likely belonged to Dendrelaphis proarchos based on their scale patterns and morphology. Beyond these four documented cases, several rescuers in the Mumbai-Thane-Gujarat belt have encountered the same species but frequently misidentified it as the Common Bronzeback (Dendrelaphis tristis), until now considered the only bronzeback species found in the region.
“The scalation and external features of these snakes closely match D proarchos from its known range in Northeast India. A photo voucher has been preserved at the Lee Kong Chian Natural History Museum in Singapore, and expert herpetologist G Vogel has confirmed the identification,” Ghadi added. The discovery challenges previous assumptions that the species’ presence in western India was due to accidental transport. Instead, it indicates a naturally occurring but previously undocumented population.
Researchers suggest this isolated population could represent a distinct genetic lineage within the pictus clade — a group known for morphologically similar but genetically unique species. A detailed molecular study is planned to determine whether this population represents D proarchos sensu stricto or an undescribed species. The discovery marks the first-ever confirmed record of Dendrelaphis proarchos in Maharashtra, highlighting western India’s untapped biodiversity and the need for further herpetological research.
