Guwahati: In a breakthrough for biodiversity research in Northeast India, scientists have reported the first confirmed sighting of the rare damselfly Coeliccia svihleri Asahina in Arunachal Pradesh. The discovery, made in October 2024 at Deban inside the Namdapha Tiger Reserve, was verified through photographic documentation in the presence of forest personnel.
The study, conducted by R. Mahesh, Rajesh Gopinath, Gaurav Joshi and Roshan Upadhaya, has been published in the Journal of Threatened Taxa.
Previously known only from Assam, Bhutan, Myanmar, and China’s Yunnan province, this is the first verifiable record of the damselfly from Arunachal Pradesh—and the first from India since 2002. Researchers say the finding not only extends the known distribution of the species but also underscores the rich yet underexplored Odonata diversity of the eastern Himalaya.
Odonata, comprising both dragonflies and damselflies, are among the most ancient and ecologically significant insect orders. Characterized by their large compound eyes, striking colours, and agile flight, these insects play a vital role as apex predators in freshwater and humid forest ecosystems, helping regulate insect populations and serving as indicators of environmental health.
During the survey, 21 Odonata species were recorded, including Trithemis aurora, Neurothemis fulvia, and Neurobasis chinensis. But the sighting of C. svihleri—only the third photographic evidence-based record from India—is seen as the most significant.
The individual was spotted along the Miao–Vijaynagar trekking path, resting in shaded riparian habitat—typical of damselflies that thrive near streams and wetlands.
“This confirmed record of C. svihleri extends its known distribution in India and adds an important data point to the region’s Odonata inventory,” the authors wrote. “The sighting in Namdapha not only fills a major gap in the species’ distribution but also highlights the rich and still largely undocumented biodiversity of the park.”
Though assessed as Least Concern by the IUCN Red List, C. svihleri remains sparsely documented across its global range. Researchers caution that the scarcity of records could be due to under-reporting or misidentification. The discovery emphasizes the need for systematic surveys of Odonata species—insects that serve as sensitive bio-indicators of freshwater ecosystem health.
The only records of C. svihleri in India are from regions located within the state of Assam, in Ledo and Kameng; in Abhoypur Forest and Naphuk. “While Assam is a neighbouring state of Arunachal Pradesh, what is noteworthy to mention here are that the geographical regions that they have been spotted is at least aerially 161–285 km away from Namdapha National Park. The finding of C. svihleri in Arunachal Pradesh extends its known range beyond Assam, where it was first described by Asahina in 1970” the authors say.
Namdapha Tiger Reserve, part of the Indo-Burma biodiversity hotspot, is already recognized for its ecological significance.
“Human-induced pressures such as deforestation, forest fragmentation, and encroachment on riparian zones continue to threaten the park’s biodiversity,” the researchers warned. “Monitoring the health of freshwater ecosystems will be critical to safeguarding species like C. svihleri. Any species that is sparsely documented and poorly understood is at risk of local extinction.”
The team added that the discovery of C. svihleri in Namdapha also points to the possibility of finding more undocumented damselfly and dragonfly species in the area. “Given the reserve’s diverse habitats and the limited surveys carried out so far, it is highly likely that other rare or even new species remain to be discovered,” they said.
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