SEM micrographs of Navicula vanseea sp. nov. SZCZEY2262 A external view of the entire valve B details of central area showing simple proximal raphe endings and shortened striae C details of apex showing the terminal fissure D, E internal view of two entire valves, showing the central area and filiform proximal raphe endings F details of apex showing well-developed helictoglossae G, H girdle view of valves showing continuous areolation on mantle and two isolated lineolae (white arrows). Scale bars: 5 μm (A, D, E, G, H); 3 μm (B, C, F).