Gomphonema duplipunctatum

Valves are rhombic-lanceolate and weakly heteropolar. Apices are narrowly rounded and not protracted. The axial area is narrow and linear. The central area is asymmetric and variable and bordered on one side by two shortened striae, each with a single isolated stigmoid near the proximal end. On the opposite side, the central area may be bordered by zero, one or two shortened striae. Raphe branches are lateral and somewhat sinuous. External proximal raphe ends are bent slightly toward the primary side of the valve. Terminal raphe ends are comma-shaped. Striae are radiate near the valve center, often, but not always, becoming parallel near the apices. Central striae are slightly bowed; the remaining striae are straight. Areolae in the striae number 35-40 in 10 µm.

Krasske (1943) described this taxon as Gomphonema bipunctatum, but that name had already been used by Zimmermann in 1915 for a different species with a different type. As such, G. bipunctatum Krasske is an illegitimate name. Lange-Bertalot & Reichardt (1996) gave the type a new name, G. duplipunctatum.