Valves are lanceolate with drawn-out apices, 32-39 µm long, 7.0-8.3 µm wide. The central area is slightly asymmetrical, elliptical. The raphe is straight, with external proximal raphe endings slightly dilated and bent towards primary side of the valve. The central nodule is asymmetrically expanded on the internal valve surface to the primary side. Striae are radiate around the center, 13-15 in 10 µm, becoming parallel then convergent at the apices.