Epithemia Argus Guide
Credit: Drew Meyers
  1. Apices rounded
  2. Proximal raphe positioned near dorsal margin
  3. Most of raphe positioned along ventral margin

Valves are dorsiventral with a convex dorsal margin and a slightly concave to nearly straight ventral margin. Valve apices are distinctly rounded. The proximal raphe is positioned at, or above 2/3 of the valve width. The rest of the raphe canal is positioned on the ventral margin to the apices. The areolae are coarse, with 4-6 striae in 10 µm. Costae number 1-4 in 10 µm.