Аннотация:The diatom genus Ninastrelnikovia was established by Lange-Bertalot and Fuhrmann (2014) as a monospecific taxon with the type species of Ninastrelnikovia gibbosa (Hustedt) Lange-Bertalot & Fuhrmann (= Navicula gibbosa Hustedt 1937). The new genus was created on the basis of its remarkable morphology which separates it from Navicula Bory (1822) sensu stricto with generitype Navicula tripunctata (O.F. Müller) Bory (Cox 1999). According to Lange-Bertalot and Fuhrmann (2014) cells of Ninastrelnikovia gibbosa are isovalvate and biraphid with a median raphe system. Interdigitating spines are partially masked by numerous granules. Valves terminating a colony lack marginal spines Valve faces that are covered by neighboring cells of the aggregation are different. The raphe is reduced to rudimentary vestiges while the central nodule appears elongated by filled-in silica. The raphe is filiform and straight. A new species, Ninastrelnikovia laosica sp. nov., is described on the basis of LM and SEM observations. This is the second taxon from the previously monospecific genus. N. laosica sp. nov. differs from N. gibbosa (Hustedt) Lange-Bertalot & Fuhrmann by having a lanceolate valve shape with a second undulation between central part of valve and valve ends. The two species from the genus share the exceptional morphological peculiarity in areola structure not typical of other naviculoid genera. Every stria present unified openings covered inside by pluriseriate covering like bast whisp. This structure of pore occlusion is similar between Ninastrelnikovia and the genus Navigiolum Lange-Bertalot, Cavacini, Tagliaventi & Alfinito. N. laosica sp. nov. so far is only known from Laos, whereas N. gibbosa has a broader distribution that includes the southeastern part of North America, Brazil, North Africa, Japan and Indonesia.