Navicula Subrhynchocephala Guide
Credit: Marina Potapova
  1. Valves linear-lanceolate with variable apices
  2. Proximal raphe endings hooked to secondary side
  3. Central striae radiate and straight, or slightly bent
  4. Areolae 24-25 in 10 μm

Valves are linear-lanceolate with subrostrate to capitate apices, 29-42 µm long, 7.5-8.9 µm wide. The central area is rounded and slightly asymmetrical. The raphe is straight, with external proximal raphe ends hooked towards the secondary side of the valve. Striae are radiate, becoming parallel, then convergent at the apices. The central striae are radiate and are straight or very slightly bent. The areolae are clearly visible under LM, approximately 24-25 in 10 μm.