Visit us at

Diatoms of the United States is now known as Diatoms of North America.
This site has been redesigned and updated, and will be closing soon.

Cymbopleura sublanceolata

Krammer 2003      Category: Asymmetrical biraphid

Cymbopleura subcuspidata


Cymbopleura subrostrata

LM scalebar = 10 µm = 40 pixels.


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.

Original Description

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

Original Description

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.

Original Images

Cite This Page:
Bahls, L. (2012). Cymbopleura sublanceolata. In Diatoms of the United States. Retrieved May 20, 2018, from

Species: Cymbopleura sublanceolata

Contributor: Loren Bahls

Reviewer: Sarah Spaulding


Krammer, K. (2003). Cymbopleura, Delicata, Navicymbula, Gomphocymbellopsis, Afrocymbella. Diatoms of Europe. Diatoms of the European Inland Waters and Comparable Habitats 4: 1-530.

Links & ID's

Index Nominum Algarum (INA)

California Academy of Sciences (CAS)

Cymbopleura sublanceolata CAS

North American Diatom Ecological Database (NADED)

NADED ID: 47187

Autecology Discussion

In North America, this taxon is known from a small pond in Mount Rainier National Park, Washington. 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