Platessa Hustedtii Guide
Credit: Marina Potapova
  1. Valves elliptic
  2. Axial area on raphe valve narrow
  3. Raphe valve with transversely elliptic or rectangular central area
  4. Rapheless valve with wide lanceolate axial area
  5. Both valves with stria density 15-18 in 10 µm

Valves are elliptic. The raphe valve has a narrow axial area and a transversely elliptic or rectangular central area. The rapheless valve has a wide lanceolate axial area and lacks a distinct central area.