SEM micrographs of Navicula vanseea sp. nov. SZCZEY2172 A external view of the entire valve B details of central area showing simple, slightly drop-shaped proximal raphe endings and shortened striae C, D details of the two apices of a single valve showing the terminal fissures E internal view of the entire valve F details of central area showing filiform proximal raphe endings in a fusiform expansion of the raphe-sternum G, H details of apices showing well-developed helictoglossae showing two isolated lineolae (white arrows). Scale bars: 10 μm (A, E); 3 μm (B–D, F–H).