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Surirella tenera

W.Greg. 1856      Category: Surirelloid
SYNONYM(S): Surirella robusta var. tenera (W.Greg.) Van Heurck 1885 

Surirella suecica


Surirella terryi

LM scalebar = 10 µm = 20 pixels.


Contributor: Tahmineh Rouzbahani - June 2016
Length Range: 75-135 µm
Width Range: 24.0-31.5 µm
Striae in 10 µm:


Valves are heteropolar, with a rounded headpole and cuneate footpole. Frustules may have a slight torsion about the apical axis. Length to width ratio is 3-4:1. A narrow-lanceolate hyaline axial area is present in the center of the valve, along the apical axis. Porcae, or transapical undulations, are usually positioned opposite each other, on either side of the apical axis. There are transapical depressions between porcae along the apical axis from headpole to footpole, forming a distinct corrugated pattern. Porcae are radiate at the apices. An alar wing is evident in girdle view. The raphe is placed in a raised canal and the canal appears about as wide as the fenestrae, which number 18-26 in 100 μm. The raphe is situated atop a raised keel, or alar wing, around the valve margin. Alar canals are visible as hollow openings associated with the porcae along the margin between the valve face and the advalvar side of the raphe system.

Original Description

Author: W.Greg. 1856
Length Range: 75-135 µm
Width Range: 24-31 µm
Striae in 10 µm:

Original Description

  1. Surirella tenera ? W. G.– This pretty form occurs in the Elchies gathering, where it is frequent, along with S. biseriata and S. nobilis, so that it can be at once distinguished from them. It has exactly the form of S. nobilis but is smaller and rather narrower in proportion. It differs from S. biseriata in having one end round, the other acute. From both of these species it differs still more in the fact of having its canaliculi very much narrower and more numerous. Its length is from 0.003 to 0.005 inch. Canaliculi fine, about 10 in 0.001 inch. It is possible that it may be the perfectly developed S. linearis, but I have not as yet been able to ascertain this.

Original Images

Cite This Page:
Rouzbahani, T. (2016). Surirella tenera. In Diatoms of the United States. Retrieved May 20, 2018, from

Species: Surirella tenera

Contributor: Tahmineh Rouzbahani

Reviewer: Mark Edlund


Foged, N. (1981). Diatoms in Alaska. Bibliotheca Phycologica, Band 53, J. Cramer, Vaduz, 317 pp.

Gregory, W. (1856). Notice of some new species of British Fresh-water Diatomaceae. Quarterly Journal of Microscopical Science, new series, London 4:1-14, pl. I.

Hemphill-Haley, E. (1990). Intertidal diatoms from Willapa Bay, Washington - application to studies of small-scale sea-level changes . Northwest Science 69: 29-45.

Hustedt, F. (1930). Bacillariophyta (Diatomeae). In: Die Subwasser Flora Mitteleuropas. (A. Pascher, ed.),10, Gustav Fischer, Jena. 468 pp.

Lange-Bertalot, H. and Krammer, K. (1987). Bacillariaceae Epithemiaceae Surirellaceae. Neue und wenig bekannte Taxa, neae Kombinationen und Synonyme sowie Bemerkungen und Erganzungen zu den Naviculaceae. Bibliotheca Diatomologica 15:289 pp.

Ognjanova-Rumenova, N.G., Botev, I.S. and Vidinova, Y. N. (2011). Using sediment diatom assemblages in the assessment of environmental changes in high-altitude lakes, Rila Mts, Bulgaria . Phytologia Balcanica 17: 173-184 .

Round, F.E., Crawford, R.M. and Mann, D.G. (1990). The Diatoms. Biology and Morphology of the Genera. Cambridge University Press, Cambridge, 747 pp.

Ruck, E.C. and Kociolek, J.P. (2005). Preliminary phylogeny of the Family Surirellaceae (Bacillariophyta). Bibliotheca Diatomologica 50: 1-236.

Van Heurck, H. (1885). Synopsis des Diatomées de Belgique. Texte. Martin Brouwers & Co., Anvers. p. 157. (description).

Whitmore, T.J. (1989). Florida diatom assemblages as indicators of trophic state and pH . Limnology and Oceanography 34: 882-895 .

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Surirella tenera CAS

NCBI Genbank Taxonomy

Surirella tenera NCBI

North American Diatom Ecological Database (NADED)

NADED ID: 65020

Autecology Discussion

Surirella tenera was observed in Waller Creek, a small stream in an urban area of Austin, Texas, USA. It was unattached and fairly abundant in the benthos. Surirella tenera was also reported to be present in Alaska, where the taxon tended to be present in alkaline environments and was described as having a global geographic distribution range (Foged 1981). Surirella tenera is classified as an oligohalobous species (Foged 1981). Oligohalobous taxa include those that prefer slightly brackish waters, as well as taxa that prefer freshwater environments but can tolerate brackish waters (Pienitz et al. 1991).

The following are examples of reports of this taxon included in a species list but lacking verifiable images. This taxon was reported in oligotrophic lakes with acidic conditions in Florida (Whitmore 1989). Hemphill-Haley (1990) reported S. tenera in middle intertidal samples of Niawiakum River in northern Willapa Bay, Washington. Also, Ognjanova-Rumenova et al. (2011) reported the greatest relative abundance of this taxon in Bliznaka, Bubreka, Okoto (Sedemte Ez- era Cirque) and Dolno Marichino, Gorno Marichi- no (Marishki cirque) lakes, the alkaline cirques of the Rila Mts, southwest Bulgaria.


Distribution of Surirella tenera in rivers of the continental U.S. based on the National Water Quality Assessment program. Retrieved 10 June 2016.

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

Surirella tenera

EMAP Response Plots

Surirella tenera

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.