Eunotia Diadema Guide
Credit: Loren Bahls
  1. Dorsal and ventral margins highly arched
  2. Dorsal margin with 6 undulations
  3. Apices broad, obtusely rounded

Eunotia diadema has large valves with highly arched dorsal and ventral margins. The dorsal margin has a constant 6 undulations. Apices are broad and obtusely rounded.