ITANAGAR, Aug 29: An Indo-German research collaboration has documented 15 species of rove beetles new to science from Arunachal Pradesh, marking a significant addition to the insect diversity of the Eastern Himalayas.
The newly discovered species belong to the genus Stenus, a highly diverse group of rove beetles commonly found in damp habitats such as stream margins, wetlands and moist leaf litter. The findings take the total number of Stenus species recorded from Arunachal Pradesh to 103, including 21 species newly recorded for India and 44 species newly recorded for the state.
The findings have been formally published in Linzer Biologische Beiträge, Volume 58(1), pages 523–569, in the research paper “Steninae aus Arunachal Pradesh, Indien (Coleoptera, Staphylinidae)”, authored by eminent taxonomist Dr Volker Puthz.
Several of the newly described species have been named in recognition of researchers associated with the project. Stenus gogoii, S dobiami and S sonui honour Dr Hiren Gogoi, Dobiam Tagam and Sonu Singh of the Department of Zoology, Rajiv Gandhi University (RGU), while S oliver and S tobias recognise Prof Oliver Betz and Tobias Mainda of the Institute of Evolution and Ecology, University of Tübingen, Germany.
The research team also acknowledged the support of indigenous communities during fieldwork in remote and difficult mountainous areas. The participating communities included the Nyishi community of Pakke Kessang, Sherdukpen and Bugun communities of the Eaglenest region in West Kameng, and Memba and Adi communities of Shi Yomi district.
The collaboration originated in 2021 when Prof Oliver Betz, a specialist in rove beetles, approached RGU to explore the insect diversity of Arunachal Pradesh. This subsequently led to a Memorandum of Understanding between RGU and the University of Tübingen in May 2023, with support from the German Research Foundation and necessary permissions from the National Biodiversity Authority and the Principal Chief Conservator of Forests (Wildlife), Arunachal Pradesh.
Between December 2024 and March 2025, researchers undertook four field expeditions covering Pakke Kessang, West Kameng and Shi Yomi districts. Specimens were collected using aspirators, sieves and sweep nets, leading to the identification of several species previously unknown to science.
The newly documented beetles are tiny, measuring between 1.9 and 6.5 mm. Rove beetles are among the most diverse insect groups globally, with more than 63,000 described species across nearly 4,000 genera.
Most Stenus species are small predators inhabiting moist environments and feed on tiny organisms such as springtails and aphids. They possess a distinctive extendable, tongue-like mouthpart that enables them to rapidly capture prey. The genus is also known for specialised adaptations, including chemical defence mechanisms and the ability of some species to move across water surfaces.
Researchers said the discovery underscores the extraordinary biodiversity of Arunachal Pradesh and suggests that many more insect species may remain undocumented in the state's largely unexplored habitats.
They expressed hope that the success of the Indo-German collaboration would encourage further systematic biodiversity surveys and strengthen international scientific cooperation in exploring and documenting the biological wealth of the Eastern Himalayas.