Cymbopleura angustata

(W.Sm.) Krammer 2003      Category: Asymmetrical biraphid
BASIONYM: Navicula angustata W.Sm. 1853
SYNONYM(S): Cymbella angustata (W.Sm.) Cleve 1894 
REPORTED AS: Cymbella angustata (Hustedt 1930, p. 351, fig. 639) | Cymbella angustata (Patrick & Reimer 1975, p. 22, plate 3, figs. 3-5) 

Cymbopleura anglica


Cymbopleura apiculata

LM scalebar = 10 µm = 80 pixels.


Contributor: Loren Bahls - August 2012
Length Range: 33-42 µm
Width Range: 6.5-8.3 µm
Striae in 10 µm: 16-18 at the valve center, 18-20 at the valve ends


Valves are lanceolate, subtly triundulate, and very slightly dorsiventral. Apices are rostrate in small specimens and subcapitate in larger specimens. The axial area is narrow and slightly arched with the concave margin towards the ventral margin. The central area is small and asymmetric with irregular borders. The raphe is lateral and follows the arch of the axial area. Proximal raphe ends are close and filiform, displaced slightly to the ventral margin. Distal raphe fissures are comma-shaped and deflected dorsally. Striae are parallel at the valve center, becoming radiate and then strongly radiate towards the apices. Areolae in the striae are not easily distinguished in LM and number 30-35 in 10 µm.

Original Description

Basionym: Navicula angustata
Author: W.Sm. 1853
Length Range: µm
Striae in 10 µm:

Original Description

Original Images

Cite This Page:
Bahls, L. (2012). Cymbopleura angustata. In Diatoms of the United States. Retrieved April 23, 2018, from

Species: Cymbopleura angustata

Contributor: Loren Bahls

Reviewer: Sam Rushforth


Cleve, P.T. (1894). Synopsis of the Naviculoid Diatoms, Part I. Kongliga Svenska-Vetenskaps Akademiens Handlingar 26(2):1-194, 5 pls.

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

Patrick, R.M. and Reimer, C.W. (1975). The Diatoms of the United States, exclusive of Alaska and Hawaii, V. 2. Monographs of the Academy of Natural Sciences of Philadelphia 13.

Smith, W. (1853). Synopsis of British Diatomaceae. John Van Voorst, London 1853. 89 pp., pls 1-31.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Cymbopleura angustata CAS

NCBI Genbank Taxonomy

Cymbella angustata NCBI

North American Diatom Ecological Database (NADED)

NADED ID: 190013

Autecology Discussion

Cymbopleura angustata is found infrequently in oligotrophic headwaters of the northern Rocky Mountains. These waters are circumneutral to alkaline (pH range: 6.98 to 9.10) with low to moderate levels of dissolved solids (specific conductance range: 71-460 µS/cm). Patrick and Reimer (1975) report this species from cool to cold water habitats in New England states, east central states, Iowa, Michigan, and Montana. Krammer (2003) reports it as widely distributed in oligotrophic waters with low to moderate electrolyte content in nordic, subarctic, and temperate regions, including the Alps.


Redrock Lake, Glacier National Park, Montana: home of Cymbopleura angustata.

Credit/Source: Loren Bahls