Krammer 2003 Category: Asymmetrical biraphid
BASIONYM: Cymbopleura sublanceolata Krammer 2003
Contributor: Loren Bahls - August 2012
Length Range: 29-50 µm
Width Range: 10.1-12.4 µm
Striae in 10 µm: 12-16 at the valve center, 16-19 near the apices
Valves are lanceolate and slightly dorsiventral, with almost equally arched dorsal and ventral margins. Apices are rostrate to subcapitate. The axial area is narrow and expands gradually towards a large rounded, somewhat rhomboid central area. The raphe is lateral and becomes filiform near the proximal ends, which are deflected slightly towards the ventral margin. Proximal raphe ends are weakly expanded and end with short hooks. The distal raphe is filiform and fissures are deflected dorsally, in the shape of a question mark. Striae are slightly radiate throughout and somewhat more closely spaced on the ventral side and near the apices. Areolae number about 35 in 10 µm.
This species is easily confused with Cymbopleura naviculiformis, which differs slightly in the shape of the valve and the degree of arch in the ventral margin.
Basionym: Cymbopleura sublanceolata
Author: Krammer 2003
Length Range: 30-64 µm
Width Range: 10.0-13.2 µm
Striae in 10 µm: 12-14 in the valve center, 15 towards the ends
Valves slightly dorsiventral, lanceolate, dorsal and ventral margins arched, tapering abruptly to rostrate or capitate ends. Length 30-64 µm, breadth 10-12 µm, post initial cells sometimes up to 13.2 µm, maximum length/breadth ratio 4.5. Axial area narrow, almost in the median line of the valve. Central area about 1/2 the valve breadth, rounded, distinctly set off, sometimes asymmetrical. Raphe lateral, narrowing towards the distal ends, appearing subtly reverse-lateral near the proximal ends. Proximal raphe ends barely expanded as central pores and somewhat ventrally tipped; terminal fissures ?-shaped and dorsally deflected. Striae radiate throughout, indistinctly punctate-lineate. Striae in the middle portion (dorsal) 12-14/10 µm, 15/10 µm towards the ends, puncta 30-33/10 µm.
Krammer, K. (2003). Cymbopleura, Delicata, Navicymbula, Gomphocymbellopsis, Afrocymbella. Diatoms of Europe. Diatoms of the European Inland Waters and Comparable Habitats 4: 1-530.
NADED ID: 47187
Cymbopleura sublanceolata has been confirmed from a small pond in Mount Rainier National Park, Washington (see photo below). This species is easily confused with C. naviculiformis and is probably more widespread in the US. Krammer (2003) reports C. sublanceolata from the Alps and from nordic and subarctic oligotrophic waters with low to moderate electrolyte content.
Frog pond above Dewey Lake, Mount Rainier National Park, Washington: home of Cymbopleura sublanceolata
Credit/Source: Ryan Davis, Adventurers and Scientists for Conservation