Nitzschia sigma

(Kützing) W. Smith 1853      Category: Nitzschioid
BASIONYM: Synedra sigma Kützing 1844

Nitzschia semirobusta


Nitzschia sinuata

LM scalebar = 10 µm = 80 pixels.


Contributor: Pat Kociolek - September 2011
Length Range: 30-200 µm
Width Range: 4.0-13.0 µm
Striae in 10 µm: 19-24


In girdle view, the frustule is distinctly sigmoid. In valve view, depending on the position of the specimen, valves may be distinctly sigmoid. Or, valves may also be linear-lanceolate in the middle of the valve, with the ends curved in opposite directions. The apices are small and capitate. The keel of the raphe is strongly exccentric. Fibula density is 7-12 in 10 µm. Valves lack an expanded central gap in the fibulae.

Original Description

Basionym: Synedra sigma
Author: Kützing 1844
Length Range: µm
Striae in 10 µm:

Original Description

Original Images

Cite This Page:
Kociolek, P. (2011). Nitzschia sigma. In Diatoms of the United States. Retrieved September 30, 2016, from

Species: Nitzschia sigma

Contributor: Pat Kociolek

Reviewer: Kalina Manoylov


Kützing, F.T. (1844). Die kieselschaligen Bacillarien oder Diatomeen. Nordhausen. 152 pp., 30 pls.

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)

Nitzschia sigma CAS

NCBI Genbank Taxonomy

Nitzschia sigma NCBI

North American Diatom Ecological Database (NADED)

NADED ID: 48087

Autecology Discussion