Guwahati:: In a remarkable breakthrough discovery for Indian biodiversity, researchers from the Ashoka Trust for Research in Ecology and the Environment (ATREE), Bengaluru, and the Litin Community Conservation Society, Simong village, have documented six butterfly species previously unknown to India.
The findings, published in the latest issue of Entomon mark a major addition to the country’s butterfly fauna and underscore the Siang Valley’s growing reputation as a biodiversity frontier in the Eastern Himalayas.
The study—authored by Monsoon Jyoti Gogoi, Rajkamal Goswami, Seena Narayanan Karimbumkara, and Agur Litin—is based on photographic evidence from the community-conserved forests of Simong village in Upper Siang district.
Their fieldwork, carried out in 2024 as part of ATREE’s Siang Valley Biodiversity Conservation Programme, resulted in the sighting of six species never before recorded in India.
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The new additions include Litin Onyx (Horaga takanamii), Narrow-banded Royal (Dacalana vui), Tibetan Duke (Euthalia zhaxidunzhui), Tibetan Sergeant (Athyma yui), Tibetan Junglequeen (Stichophthalma neumogeni renqingduojiei), and Mountain Columbine (Stiboges elodinia).
Until now, these species were known only from Laos, Thailand, Vietnam, Myanmar, and southeastern Tibet. Their sighting in Arunachal Pradesh significantly extends their known distribution range and strengthens the evidence of biogeographic continuity between the Metok region of Tibet and India’s Siang Valley, both linked by the Yarlung Tsangpo or Brahmaputra River.
As the study notes, “The Brahmaputra River appears to play a critical biogeographic role, facilitating faunal continuity between southeastern Tibet and eastern Arunachal Pradesh.”
One of the standout discoveries, Horaga takanamii, previously known only from Laos, has been named the “Litin Onyx” in recognition of the Litin clan of the Adi community, who continue to protect their forest through traditional conservation practices. The researchers observed the butterfly laying eggs on its host plant Symplocos sp., a rare ecological documentation.
Equally remarkable is the finding of the Tibetan Junglequeen, previously thought to exist only in Metok, Tibet. The study reveals that it “was found to be relatively common in Simong Forest, with an average of 20 individuals encountered daily,” emphasizing the lack of prior systematic surveys in the region.
In just seven days of surveys, the team recorded 90 butterfly species, underscoring how much remains undocumented in India’s Eastern Himalayas. “The documentation of six previously unrecorded species within a short one-month survey underscores the striking lack of Lepidopteran surveys and conservation attention in the Indian Eastern Himalayas,” the study observes.
The discovery not only deepens India’s natural history but also reaffirms the vital role of local communities and indigenous conservation in protecting the last great wild landscapes of the Eastern Himalayas.