Pseudostaurosira pseudoconstruens

(Marciniak) Williams and Round 1987      Category: Araphid
BASIONYM: Fragilaria pseudoconstruens Marciniak 1982

Pseudostaurosira parasitica


Pseudostaurosira robusta

LM scalebar = 10 µm = 80 pixels.


Contributor: Thomas C. Smith - June 2013
Length Range: 8-16 µm
Width Range: 3.5-7 µm
Striae in 10 µm: 8.5 near the center increasing to 18 at the apices


Valves are cruciform, with a round to rhombic inflation and broadly rounded rostrate to slightly capitate apices. In girdle view, valves are rectangular and the central inflation is distinct. The axial area may be wide in the valve center, to relatively narrow. Striae are mostly restricted to the margins and never meet in the central area. The central striae are longer than distal striae. The central striae are parallel to slightly radiate and often appear wider at the margin than proximally. The distal striae are short and parallel. Striae are uniseriate, with round to elliptical areolae.

This species was described from Holocene lake sediments in Poland (Marciniak, 1982).

Original Description

Basionym: Fragilaria pseudoconstruens
Author: Marciniak 1982
Length Range: µm
Striae in 10 µm:

Original Description

Original Images

Cite This Page:
Smith, T. (2013). Pseudostaurosira pseudoconstruens. In Diatoms of the United States. Retrieved October 22, 2016, from

Species: Pseudostaurosira pseudoconstruens

Contributor: Thomas C. Smith

Reviewer: Eduardo Morales


Marciniak, B. (1982). Late Glacial and Holocene new diatoms from a glacial Lake Przedni Staw in the Przedni Stawów Polskich Valley, Polish Tatra Mts. Acta Geol. Acad. Sci. Hung. 25: 161-171.

Marciniak, B. (1988). Late glacial Fragilaria flora from lake sediments of the Tatra Mts. and the Alps. Proceedings of the Ninth International Diatom Symposium, (F.E. Round, ed) Biopress, Bristol.

Williams, D.M. and Round, F.E. (1987). Revision of the genus Fragilaria. Diatom Research 2: 267-288.

Links & ID's

Index Nominum Algarum (INA)

California Academy of Sciences (CAS)

Pseudostaurosira pseudoconstruens CAS

North American Diatom Ecological Database (NADED)


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 pseudoconstruens

EMAP Response Plots

Pseudostaurosira pseudoconstruens

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.