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Cyclostephanos invisitatus

(M.H.Hohn and Hellermann) E.C.Ther., Stoermer and Håk. 1998      Category: Centric
BASIONYM: Stephanodiscus invisitatus M.H.Hohn and Hellermann 1963

Cyclostephanos dubius


Cyclotella atomus

LM scalebar = 10 µm = 80 pixels.


Contributor: David R.L. Burge | Mark Edlund - September 2015
Diameter: 7.8-15.1 µm
Rows of areolae in 10 µm: 15-16 based on chord count, 12-15 based on circumferential density


Valves are discoid, with a flat valve face. Striae are fine and punctate. Striae are radiate, bundled into fascicles and uniseriate in the center becoming biseriate near the margin. Fascicles originate from a central annulus and number 15-16 in 10 µm (based on chord count), 12-15 based on circumferential density. Fascicles are branching in some specimens. Areolae are fine, occurring 16-17 in 10 µm, and are visible only in larger specimens. Short, spatulate spines are present near the margin on every interfasicle. Usually one central fultoportula is present, but occasionally two fultoportulae are present.

The location of the fultoportulae is variable, according to Houk et al. (2014) and may be located anywhere from near the central annulus to near the valve margin.

Original Description

Basionym: Stephanodiscus invisitatus
Author: M.H.Hohn and Hellermann 1963
Diameter: 9.2-11.4 µm
Rows of areolae in 10 µm: 16

Original Description

Valves circular, diameter 9.2-11.4 µ; striae finely punctate, 16/10 µ; short submarginal recurved spines in indistinct hyaline interspaces; center of valve finely punctate, irregular.

Original Images

Cite This Page:
Burge, D., and Edlund, M. (2015). Cyclostephanos invisitatus. In Diatoms of the United States. Retrieved May 24, 2018, from

Species: Cyclostephanos invisitatus

Contributor: David R.L. Burge | Mark Edlund

Reviewer: Kalina Manoylov


Edlund, M.B., Engstrom, D.R., Triplett, L.D., Lafrancois, B.M. and Leavitt, P.R. (2009). Twentieth century eutrophication of the St. Croix River (Minnesota-Wisconsin, USA) reconstructed from the sediments of its natural impoundment. Journal of Paleolimnology 41(4): 641-657. 10.1007/s10933-008-9296-1

Hohn, M.H. and Hellerman, J. (1963). The taxonomy and structure of diatom populations from three Eastern North American rivers using three sampling methods. Transactions of the American Microscopical Society 82(3):250-329.

Houk, V., Klee, R. and Tanaka, H. (2014). Atlas of freshwater centric diatoms with a brief key and descriptions Part IV. Stephanodiscaceae B: Stephanodicsus, Cyclostephanos, Pliocaenicus, Hemistephanos, Stephanocostis, Mesodictyon & Spicaticribra. In: Poulícková, A. (ed.): Fottea 14 Supplement, 529 pp.

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.

Theriot, E., Stoermer, E. & Håkansson, H. (1987). Taxonomic interpretation of the rimoportula of freshwater genera in the centric diatom family Thalassiosiraceae. Diatom Research 2(2): 251-265. 10.1080/0269249X.1987.9705003

Tibby, J. and Reid, M.A. (2004). A model for inferring past conductivity in low salinity waters derived from Murray River (Australia) diatom plankton. Marine and Freshwater Research 55: 597-607.

Yang, X., Dong, X., Gao, G., Pan, H., and Wu, J. (2005). Relationship between surface sediment diatoms and summer water quality in shallow lakes of the middle and lower reaches of the Yangtze River. Journal of Integrative Plant Biology 47(2): 153–164. 10.1111/j.1744-7909.2005.00035.x

Links & ID's

Index Nominum Algarum (INA)

Original INA
Transfer INA

California Academy of Sciences (CAS)

Cyclostephanos invisitatus CAS

NCBI Genbank Taxonomy

Cyclostephanos invisitatus NCBI

North American Diatom Ecological Database (NADED)

NADED ID: 19002

Autecology Discussion

Cyclostephanos invisitatus is planktonic and regarded as an indicator of eutrophic conditions in rivers (Edlund et al. 2009) and shallow lakes (Yang et al. 2005). Observed in all of the Laurentian Great Lakes, Reavie and Kireta (2015) found C. invisitatus to have a high total phosphorus optimum and most common in Lake Erie. Tibby and Reed (2004) found C. invisitatus to be more abundant in Iow salinity waters. In addition to observing a low conductivity optimum for C. invisitatus, Reavie & Smol (1998) sampled C. invisitatus from the epilithon, epiphyton, and the plankton of the St. Lawrence River.


Distribution of Cyclostephanos invisitatus in rivers of the continental U.S. based on the National Water Quality Assessment program. Retrieved 03 June 2015.

Credit/Source: USGS BioData

EMAP Assessment

The Environmental Protection Agency (EPA) western Environmental Monitoring and Assessment Program (EMAP) study was completed during the years 2000-2004 (see citations at bottom of this page). Over 1200 streams and rivers in 12 western states (Arizona, California, Colorado, Idaho, Montana, Nevada, North Dakota, Oregon, South Dakota, Utah, Washington and Wyoming) were selected for sampling based on a stratified randomized design. This type of design insures that ecological resources are sampled in proportion to their actual geographical presence. Stratified randomized design also allows for estimates of stream length with a known confidence in several “condition classes” (good or least-disturbed, intermediately-disturbed, and poor or most-disturbed) for biotic condition, chemistry and habitat.

EMAP Distribution

Cyclostephanos invisitatus

EMAP Response Plots

Cyclostephanos invisitatus

EMAP citations

Results are published in:

Johnson, T., Hermann, K., Spaulding, S., Beyea, B., Theel, C., Sada, R., Bollman, W., Bowman, J., Larsen, A., Vining, K., Ostermiller, J., Petersen, D. Hargett, E. and Zumberge, J. (2009). An ecological assessment of USEPA Region 8 streams and rivers. U.S. Environmental Protection Agency Region 8 Report, 178 p.

Stoddard, J. L., Peck, D. V., Olsen, A. R., Larsen, D. P., Van Sickle, J., Hawkins, C. P., Hughes, R. M., Whittier, T. R., Lomnicky, G. A., Herlihy, A. T., Kaufman, P. R., Peterson, S. A., Ringold, P. L., Paulsen, S. G., and Blair, R. (2005). Environmental Monitoring and Assessment Program (EMAP) western streams and rivers statistical summary. U.S. Environmental Protection Agency Report 620/R-05/006, 1,762 p.

Stoddard, J. L., Peck, D. V., Paulsen, S. G., Van Sickle, J., Hawkins, C. P., Herlihy, A. T., Hughes, R. M., Kaufman, P. R., Larsen, D. P., Lomnicky, G. A., Olsen, A. R., Peterson, S. A., Ringold, P. L., and Whittier, T. R. (2005). An ecological assessment of western streams and rivers. U.S. Environmental Protection Agency Report 620/R-05/005, 49 p.