Placoneis Amphibola Guide
Credit: Mark Edlund
  1. Valves elliptic
  2. Apices rostrate
  3. Striae coarse
  4. Central area bowtie-shaped
  5. Raphe undulate, lateral

Valves are elliptic, with rostrate apices. The central area is bowtie-shaped. Stria and areola density is coarse. The raphe is undulate, lateral and has expanded proximal ends.