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Guide to Psammothidium sacculus

(J.R. Carter) Bukhtiyarova 1996

Psammothidium sacculum guide
  1. Valves elliptic to linear-elliptic
  2. Raphe valve with transversely rectangular or bow-tie shaped central area
  3. Rapheless valve with narrow rhombic axial area
  4. Striae radiate
  5. Areolae often distinct in LM

Valves are elliptic to linear-elliptic. The raphe valve has a transversely rectangular (or bow-tie) shaped central area bordered by a few striae of various lengths. The rapheless valve has a narrow rhomboid axial area, which widens in the valve center into small and often asymmetric central area. Striae are radiate on both valves. Areolae are visible in LM.