Stephanodiscus minutulus

(Kütz.) Round 1981      Category: Centric
BASIONYM: Cyclotella minutula Kütz. 1844
SYNONYM(S): Stephanodiscus astraea var. minutula (Kütz.) Grunow in Van Heurck | Stephanodiscus minutulus (Kütz.) Cleve and J.D.Möller | Stephanodiscus minutulus Grunow 

Stephanodiscus hantzschii f. tenuis


Stephanodiscus niagarae

LM scalebar = 10 µm = 80 pixels.


Contributor: David R.L. Burge | Mark Edlund - February 2017
Diameter: 6-10 µm
Rows of areolae in 10 µm: 8-13 based on circumferential density


Valves are small and disc-shaped, with a concentrically undulate valve face. Valve faces are complementary, with scutate (raised) and lacunate (depressed) valves. Areolae are scattered at the valve center and arranged in multiseriate fascicles toward the margin. Areolae number 2-3 per fascicle near the margin, but in many specimens, the areolae may not be resolvable at the margin. The interfascicles are narrow and uniform in width. They may vary across specimens by being either wavy or straight. A small spine is present between each fascicle, at the interfascicle and face/mantle junction. A single fultoportula is present near center of the valve face, a feature is usually not observable in LM. Marginal strutted processes are located on the mantle beneath every 4-5th spine.

Original Description

Basionym: Cyclotella minutula
Author: Kütz. 1844
Diameter: 10 µm
Rows of areolae in 10 µm:

Original Description

C. minor, latere secundarie radiatim striato, flexuoso.

Original Images

Cite This Page:
Burge, D., and Edlund, M. (2017). Stephanodiscus minutulus. In Diatoms of the United States. Retrieved April 24, 2018, from

Species: Stephanodiscus minutulus

Contributor: David R.L. Burge | Mark Edlund

Reviewer: Matthew Julius


Cleve, P.T. and Möller, J.D. (1882). Upsala: Esatas Edquists Boktryckeri. Diatoms (exsiccata), Part VI: 277-324.

Cumming, B.F., Wilson, S.E., Hall, R.I. and Smol, J.P. (1995). Diatoms from British Columbia (Canada) Lakes and their relationship to salinity, nutrients and other limnological variables. Bibliotheca Diatomologica 31: 1-207.

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

Reavie, E.D. and Kireta, A.R. (2015). Centric, Araphid and Eunotioid Diatoms of the Coastal Laurentian Great Lakes. Bibliotheca Diatomologica 62:1-184.

Reavie, E.D. and Smol, J.P. (1998). Freshwater diatoms from the St. Lawrence River. Bibliotheca Diatomologica Band 41. J. Cramer, Berlin. 137 pp.

Reavie, E.D., Smol, J.P., Sharpe, I.D., Westenhofer, L.A. and Roberts, A.M. (2000). Paleolimnological analyses of cultural eutrophication patterns in British Columbia lakes. Canadian Journal of Botany 78(7): 873-888.

Round, F.E. (1981). The diatom genus Stephanodiscus: an electron-microscopic view of the classical species. Archiv für Protistenkunde 124: 455-470.

Spamer, E.E. and Theriot, E.C. (1997). Stephanodiscus minutulus,” “S. minutus,” and similar epithets in taxonomic, ecological, and evolutionary studies of modern and fossil diatoms (Bacillariophyceae: Thalassiosiraceae) - A century and a half of uncertain taxonomy and nomenclatural hearsay. Proceedings of the Academy of Natural Sciences of Philadelphia 148: 231-272.

Stoermer, E. F. and Yang, J. J. (1969). Plankton diatom assemblages in Lake Michigan. Univ. Michigan, Great Lakes Res. Div. Spec. Rep. No. 47, 168 pp.

Links & ID's

Index Nominum Algarum (INA)

Transfer INA
Original INA

California Academy of Sciences (CAS)

Stephanodiscus minutulus CAS

NCBI Genbank Taxonomy

Stephanodiscus minutulus NCBI

North American Diatom Ecological Database (NADED)

NADED ID: 64018

Autecology Discussion

The planktonic species S. minutulus is common in meso- to eutrophic lakes and large rivers of North America (Cumming et al. 1995, Reavie and Smol 1998, Reavie and Kireta 2015). In the Laurentian Great Lakes, it reaches its greatest abundance in productive nearshore regions, the mouths of large rivers and coastal embayments (Stoermer and Yang 1969). Increased abundance of S. minutulus in paleolimnological records is a strong indicator of cultural eutrophication (Reavie et al. 2000).


Distribution of Stephanodiscus minutulus in streams of the continental United States.

Credit/Source: USGS/Biodata