Gomphoneis Variabilis Guide
Credit: Pat Kociolek
  1. Valves lanceolate-clavate
  2. Longitudinal lines distinct near the axial area
  3. Striae 10-13 in the center valve, 14-16 at the poles

Valves are lanceolate-clavate. Smaller valves are elliptical-clavate, with the headpole protracted slightly. Striae are radiate at the central portion of the valve and strongly radiate at the poles. A small, barely circular central area with a single stigma is present. Longitudinal lines are distinct near the axial area, less so at the apices.