A fossil freshwater diatom species, Thalassiosira inlandica sp. nov., is described from Pleistocene lacustrine sediments of
the Kathmandu Basin on the southern slope of the Nepal Himalaya. Thalassiosira inlandica is characterized by (1) a
nonplicated (flat) valve face, (2) networks of ribs and costae, (3) semicontinuous cribra composed of the aggregate of many
pore rows, (4) absence of valve face fultoportula, (5) elongated marginal fultoportulae, and (6) multiple rimoportulae in the
mantle area. This new species is compared with allied taxa based on several morphological character