P Chlidanos Guide Copy
Credit: Marina Potapova
  1. Valves linear-elliptical, often slightly gibbous at midvalve
  2. Both valves with linear axial area
  3. Both valves with transversely rectangular central area
  4. Raphe straight, without terminal raphe fissures

Valves are linear-elliptical, often slightly gibbous at midvalve. Both valves have a linear axial area and transversely rectangular central area. The raphe is straight, without terminal raphe fissures. Striae are radiate on both valves, 27-33 in 10 µm, interrupted at the valve margin.