Gomphoneis Trullata Guide
Credit: Pat Kociolek
  1. Valves broadest below the central nodule
  2. Raphe distinctly undulate
  3. Longitudinal lines submarginal to half way between the margin and axial area
  4. Valves lanceolate-trullate

Valves are lanceolate-trullate and broadest below the central nodule. The raphe is lateral and distinctly undulate. Longitudinal lines are submarginal in larger specimens and are positioned about mid way between the margin and axial area in smaller specimens.