Cyclotella Antiqua Guide
Credit: Loren Bahls
  1. Central star-shape
  2. Striae unequal in length
  3. Shadow lines visible

Valves are small to moderate sized, with a unique central star-shaped cluster of triangular punctate fields. Shadow lines, termed Schattenlinien in German texts, are visible among the striae. Striae are slightly unequal in length.