A = External valve views; B = Frustule in girdle view; C = Internal views with fultoportulae and rimoportula. (A-C SEM); D = Valve with fultoportulae (DIC)
Size: Diameter = 3-10,5 µm
Note: Common in the surface waters of Gullmarsfjorden and the fjord system inside Orust. Common in rivers, lakes and coastal brackish waters (Håkansson & Clarke 1997)
Distinctive features: Distinct fultoportulae at every third to fifth costa. Central area smooth and mostly with one fultoportula
Similar species: Cyclotella choctawhatcheenana
Hasle, G. R. 1962. Three Cyclotella species from marine localities studied in the light and electron microscopes. Nova Hedwigia. 4: 299-307.
Håkansson, H. & Clarke, K.B. 1997. Morphology and taxonomy of the centric diatom Cyclotella atomus. Nova Hedwigia. 65: 207-219.
Schoeman, F. R. & Archibald, R. E. M. 1976. The diatom flora of South Africa. National Institute for Water Research CSIR. Special Report WAT 50.