Cells have one chloroplast, one valve with processes and one without. Cells are curved in a broad girdle view. The outline of valves varies with the length of the apical axis. Smaller valves are oblong to sub-circular, larger valves are more narrow and lanceolate. Cells with characteristic pili, but often lacking in small cells.
Morphometrics: apical axis: 1.2-13 µm, transapical axis: 0.7-1.5: pervalvar axis: 1-17 µm.
Distribution: Norwegian coastal waters, Barents Sea