We describe Adlafia kociolekii sp. nov. from aerial habitats in Sikkim, India, a part of the Eastern Himalayas. The species is described based on light and scanning electron microscopic observations. The main diagnostic features include valves are clear elliptical, a narrow axial area at the centre, radiate to convergent striation, and distinctive Voigt discontinuity at both apices. In terms of ... [Show full abstract] ultrastructure, the features that identify this species as new are the internally presence of raphe on the elevated sternum, with distal raphe ends distinctly deflected to opposite sides of proximal ends, and distal ends terminating in long and thickened helictoglossae. The species was also recorded from wet walls and freshwater habitats of northeast India, in the present study. The morphological features of the species are compared with other closely similar taxa of Adalfia and other naviculoid genera.