Fig. 2. SEM. Left valve. Anterior end with flattened to curved apical collar. Intercalary band smooth and wide.
Fig. 3. SEM. Apical view. Apical collar on left valve appears as a rounded lip bordering the periflagellar area. Both valves anteriorly excavated. Valve center slightly concave. Foreign material on cell surface.
Fig. 4. SEM. Periflagellar area: apical view. A V-shaped depression on right valve set in a broad triangle bordered by flattened apical collar on left valve. Flagellar pore larger than auxiliary pore. Large accessory pore adjacent to flagellar pore (double arrows); 3 smaller accessory pores adjacent to auxiliary pore (arrowheads). A=auxiliary pore; F=flagellar pore.
Fig. 5. SEM. Periflagellar area. Narrow curved periflagellar collar wraps around auxiliary pore (large double arrows). Position of accessory pores: large (small double arrows) and small (arrowhead).
Fig. 6. SEM. Areolae round to oval with smooth margins. Some with oblong-shaped trichocyst pores (arrows).
Fig. 7. LM. Right valve. Marginal areolae give appearance of a flared ridge.
Fig. 8. LM. Right valve. Posterior nucleus. N=nucleus.