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Pseudostaurosira brevistriata

(Grunow) D.M.Williams and Round 1987      Category: Araphid
BASIONYM: Fragilaria brevistriata Grunow in Van Heurck 1885

Pseudostaurosira americana


Pseudostaurosira elliptica

LM scalebar = 10 µm = 80 pixels.


Contributor: Eduardo A. Morales - October 2010
Length Range: 10-26 µm
Width Range: 3.5-4 µm
Striae in 10 µm: 12-15


Valves are lanceolate in larger specimens to elliptical in smaller specimens, 3.5-4 µm wide by 8-26 µm long. Valves have rostrate ends in larger specimens to rounded ends in smaller specimens. The valve face is flat and the transition between the valve face and the mantle is gradual. The axial area is widely lanceolate. In girdle view, frustules are rectangular, joined by linking spines. Colonies may be planktonic or attached to the substratum at one end by a frustule with a mucilage pad. Striae are short, distinct, extending onto the mantle, composed of wide, round to oval areolae, 12-15 in 10 µm, parallel to radiate in the central of the valve to slightly radiate toward the valve ends. Costae are broad. Spines are spatulate, solid, some with terminal digitations that attach to the neighboring valve lineolae. Spines are present along the valve face edge, except at the apices, and always located on striae. Apical pore fields with round poroids are present on the valve mantle close to valve face. Copulae (girdle bands) are open and lack perforations.

US collected samples show a wide range of morphological variants sometimes mixed in material from a single locality. The origin of these variants is uncertain as is their taxonomic affinity. Here we follow the interpretation of Patrick and Reimer (1966) and present populations that resemble the iconotype of Van Heurck (1885).

Original Description

Basionym: Fragilaria brevistriata
Author: Grunow in Van Heurck 1885
Length Range: µm
Striae in 10 µm:

Original Description

Valve lancéolée à extrémités diminuées-rostrées; stries très-courtes et marginales, au nombre de 13 à 14 en 1 c.d.m. Longueur 1 ¼ à 2 c.d.m. Eaux douces. - Bruxelles (Delogne).

Original Images

Cite This Page:
Morales, E. (2010). Pseudostaurosira brevistriata. In Diatoms of the United States. Retrieved May 22, 2018, from

Species: Pseudostaurosira brevistriata

Contributor: Eduardo A. Morales

Reviewer: Sam Rushforth


Edlund, M.B., Morales, E.A. and Spaulding, S.A. (2006). The type and taxonomy of Fragilaria elliptica Schumann, a widely misconstrued taxon. In: Witkowski, A. (Ed.). Proceedings of the 18th International Diatom Symposium. Miedzyzdroje, Poland. pp 53-59. Biopress Limited, Bristol, England.

Patrick, R.M. and Reimer, C.W. (1966). The Diatoms of the United States exclusive of Alaska and Hawaii, V. 1. Monographs of the Academy of Natural Sciences of Philadelphia 13.

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

Williams, D.M. and Round, F.E. (1987). Revision of the genus Synedra Ehrenb. Diatom Research 1(2): 313-339.

Links & ID's

Index Nominum Algarum (INA)

Original INA
Transfer INA

California Academy of Sciences (CAS)

Pseudostaurosira brevistriata CAS

NCBI Genbank Taxonomy

Pseudostaurosira brevistriata NCBI

North American Diatom Ecological Database (NADED)

NADED ID: 73001

Autecology Discussion

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

Pseudostaurosira brevistriata

EMAP Response Plots

Pseudostaurosira brevistriata

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.