Nitzschia Biacrula Guide
Credit: Kalina Manoylov
  1. Valves sigmoid in girdle view
  2. Fibulae coarse and irregular
  3. Raphe positioned in the middle of the valve face

Valve linear-lanceolate with strongly sigmoid, beaked ends. Raphe parallel to slightly sigmoid, positioned nearly in the middle of the valve. Fibulae are irregular in size and spacing, approximately 8-9 in 10 ┬Ám. Valves sigmoid in girdle view. Striae are not discernible.