Cymbella designata

Valves are broadly lanceolate and moderately dorsiventral with strongly arched dorsal and ventral margins. Apices are apiculate and extend laterally from the ends of the valve. The axial area is about 1/4 to 1/5 the valve width, curved, and narrower near the apices. The central area is slightly tumid and scarcely wider than the axial area. Raphe branches are weakly lateral near their centers and filiform towards the proximal and distal ends. Proximal raphe ends are slightly expanded and displaced ventrally. Distal raphe ends are comma-shaped and deflected dorsally. Striae are radiate throughout. Areolae in the striae number 26-30 in 10 µm.

The nomenclatural history of this taxon is convoluted. Krammer (1985) proposed that Cymbella leptoceros var. rostrata Hustedt is morphologically dissimilar to Cymbella leptoceros and should, therefore, be elevated to the rank of species, creating the new name and rank of Cymbella designata Krammer. Later, Lange-Bertalot and Genkal (1999) suggested that Cymbella designata belongs in Cymbopleura (p. 226, figs 56: 17-19) but they failed to formally transfer the species, so the name Cymbopleura designata is invalid.

In 2003, Krammer published the new species Cymbopleura citriformis, which appears to be conspecific with Cymbella designata. The type of the basionym Cymbella leptoceros var. rostrata Hustedt 1942, which is Cymbella designata, has nomenclatural priority.