Abstract
Ninastrelnikovia lateritica sp. nov., a new and rare freshwater biraphid diatom species was discovered from a rocky ephemeral pool of the Kaas plateau, Western Ghats, and described on the basis of light and scanning electron microscopy observations. A morphological comparison with the two other described Ninastrelnikovia taxa is provided. This new species can easily be separated from its congeners by the shape of the valve apex and absence of any second inflation along the valve margin, as well as the shape and structure of the external distal raphe ends and internal proximal raphe ends. The members of Ninastrelnikovia are characterized by two morphological types of valves. Valves on the ends of colonies exhibit one set of morphological features while valves located in the middle of colonies show another set of morphological features. Morphological details of the valves are discussed.