Scientists from the University of Delhi have discovered two new slender-armed frog species in the remote mountains of Arunachal Pradesh. One species is named Soman’s Slender Arm Frog (Leptobrachium somani) to honor late journalist E. Somanath for his environmental work. The second species is called Mechuka Slender Arm Frog (Leptobrachium mechuka), found near Mechuka town. The discovery was published in the US journal PeerJ after more than three years of field surveys across five northeast States. Led by herpetologist Prof. S.D. Biju and doctoral student A.N. Dikshit Akalabya Sarmah, the team studied slender-armed frogs of the genus Leptobrachium found in South and Southeast Asia. They used DNA analysis, morphology, bioacoustics, and 3D micro-CT scans to confirm these species were new to science. Soman’s Slender Arm Frog is small, about 55 mm long, with a greyish-brown body and silver-grey to light-blue eyes. It lives in evergreen forest near forest stream banks where males call. Mechuka Slender Arm Frog is slightly larger at 60 mm, with a brown and reddish body and silvery-white eyes, found in evergreen forests and nearby grasslands. The study showed the Brahmaputra river acts as a natural divider, with the new species on its north side and other slender-arm frogs located south. Prof. Biju said, "These findings show how large rivers shape the spread and evolution of slender-armed frogs." Arunachal Pradesh is part of the Himalaya biodiversity hotspot, rich in unique plants and animals. The new frogs join the family Megophryidae, which has 366 known species including Asian horned frogs, and the genus Leptobrachium now has around 40 species. This research highlights the amazing diversity of life waiting to be discovered in India’s remote forests.