Synedra cyclopum

Brutschy 1922      Category: Araphid
SYNONYM(S): Fragilaria cyclopum (Brutschy) Lange-Bert. 1980 

Surirella terryi


Synedra famelica

LM scalebar = 10 µm = 40 pixels.


Contributor: Loren Bahls - May 2012
Length Range: 31-70 µm
Width Range: 3.2-7.3 µm
Striae in 10 µm: 15-18


Valves are linear to linear-lanceolate and arcuate, with gradually attenuated subcapitate ends. The axial area is linear and very narrow, widening near the central area. The central area is longer than broad, extends to the valve margins, and often contains ghost striae. The central area is not swollen and may be slightly indented on the concave side of the valve in smaller specimens. Areolae in the striae are indistinct in LM.

Original Description

Author: Brutschy 1922
Length Range: µm
Striae in 10 µm:

Original Description

Original Images

Cite This Page:
Bahls, L. (2012). Synedra cyclopum. In Diatoms of the United States. Retrieved April 21, 2018, from

Species: Synedra cyclopum

Contributor: Loren Bahls

Reviewer: Sarah Spaulding


Brutschy, A. (1922). Die Vegetation und der Zooplankton des Hallwiler Sees. Internationale Revue der gesamten Hydrobiologie 10: 91-138, 271-298. 10.1002/iroh.19220100108

Gaiser, E.E. and Bachmann, R.W. (1993). The ecology and taxonomy of epizoic diatoms on Cladocera. Limnology and Oceanography, 38 (3): 628-637.

Krammer, K. and Lange-Bertalot, H. (1991). Bacillariophyceae. 3. Teil: Centrales, Fragilariaceae, Eunotiaceae. In Ettl, H., Gerloff, J., Heynig, H. & Mollenhauer, D. (Eds.). Süsswasserflora von Mitteleuropa. 2(3): 1-576. Gustav Fisher Verlag, Stuttgart, Germany.

Patrick, R.M. and Reimer, C.W. (1966). The Diatoms of the United States exclusive of Alaska and Hawaii, V. 1. Monographs of the Academy of Natural Sciences of Philadelphia 13.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Synedra cyclopum CAS

North American Diatom Ecological Database (NADED)

NADED ID: 66013

Autecology Discussion

Synedra cyclopum is uncommon and widely dispersed in the plankton of lakes and reservoirs (and in streams below lakes and reservoirs) in the western United States. Patrick and Reimer (1966) report that it is often attached to crustacea in cool water. In Europe, Krammer and Lange-Bertalot (1991) report it from lakes of medium electrolyte content, where it lives on copepods.


Gates of the Mountains on the Missouri River below Hauser Dam, Lewis and Clark County, Montana: home of Synedra cyclopum.

Credit/Source: Loren Bahls