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Sellaphora bacilloides

(Hust.) Levkov, Krstic and Nakov 2006      Category: Symmetrical biraphid
BASIONYM: Navicula bacilloides Hust. 1945

Sellaphora auldreekie


Sellaphora bacillum

LM scalebar = 10 µm = 80 pixels.


Contributor: Loren Bahls - February 2012
Length Range: 30-35 µm
Width Range: 10.0-12.6 µm
Striae in 10 µm: 18 (center) -26 (ends)


Valves are elliptic with bluntly rounded, subtly protracted apices. The axial area is very narrow. The central area is circular and about half the width of the valve. Proximal raphe ends are dilated, straight and extend into the central area. Striae are radiate; they are shorter and more widely spaced about the central area. Areolae are very fine and number about 40 in 10 µm.

Original Description

Basionym: Navicula bacilloides
Author: Hust. 1945
Length Range: 20-30 µm
Width Range: 10-11 µm
Striae in 10 µm: 22-24

Original Description

Original Images

Cite This Page:
Bahls, L. (2012). Sellaphora bacilloides. In Diatoms of the United States. Retrieved May 26, 2018, from

Species: Sellaphora bacilloides

Contributor: Loren Bahls

Reviewer: Rex Lowe


Hustedt, F. (1945). Diatomeen aus Seen und Quellgebieten der Balkan-Halbinsel. Archiv für Hydrobiologie 40(4):867-973.

Krammer, K. and Lange-Bertalot, H. (1986). Bacillariophyceae. 1. Teil: Naviculaceae. In: Ettl, H., J. Gerloff, H. Heynig and D. Mollenhauer (eds.) Süsswasserflora von Mitteleuropa, Band 2/1. Gustav Fisher Verlag, Jena. 876 pp.

Levkov, Z., Nakov, T. and Metzeltin, D. (2006). New species and combination from the genus Sellaphora Mereschkowsky from Macedonia. Diatom Research 21 (2): 297-312. 10.1080/0269249X.2006.9705671

Simonsen, R. (1987). Atlas and Catalogue of the Diatom Types of Friedrich Hustedt. J. Cramer, Berlin & Stuttgart 1: 525 pp.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Sellaphora bacilloides CAS

North American Diatom Ecological Database (NADED)

NADED ID: 46490

Autecology Discussion

There are 23 records of Sellaphora bacilloides in the Montana Diatom Collection, from lakes and low-gradient streams in arid regions throughout the Northwest United States. This uncommon species prefers alkaline waters (mean pH = 7.8) with somewhat elevated electrolytes (mean specific conductance = 689 µS/cm).


Little Dry Creek at Flowing Well, Garfield County, Montana: home of Sellaphora bacilloides.

Credit/Source: Loren Bahls

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

Sellaphora bacilloides

EMAP Response Plots

Sellaphora bacilloides

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.