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Diatoms of the United States is now known as Diatoms of North America.
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Psammothidium chlidanos

(M.H.Hohn and Hellerman) Lange-Bert. 1999      Category: Monoraphid
BASIONYM: Achnanthes chlidanos M.H.Hohn and Hellerman 1963

Psammothidium bioretii


Psammothidium curtissimum

LM scalebar = 10 µm = 80 pixels.


Contributor: Marina Potapova - August 2010
Length Range: 12-18 µm
Width Range: 4.8-6.2 µm
Striae in 10 µm: 27-33


Valves are linear-elliptical, often slightly gibbous at midvalve. Both valves have a linear axial area and transversely rectangular central area. The raphe is straight, without the terminal raphe fissures. The central and terminal raphe ends are slightly expanded externally. The central raphe ends curve toward opposite sides internally. The striae are radiate on both valves, 27-33 in 10 µm, interrupted at valve margin. One row of areolae is present on the margin of both valves. Areolae are 34-42 in 10 µm within the striae. The external openings of the areolae are isodiametric to transapically elongated.

Original Description

Basionym: Achnanthes chlidanos
Author: M.H.Hohn and Hellerman 1963
Length Range: 13.5-15.1 µm
Width Range: 5.7-6.2 µm
Striae in 10 µm: 28-32

Original Description

Valve elliptic, sides nearly parallel; striae radiate throughout, straight, non-punctate, 28-32/10 μ at ends, slightly coarser at center; central area transversely rectangular; rapheless valve: axial area narrow at ends expanding toward center to form ovoid rectangular area; length 13.5-15.1 μ, width 5.7-6.2 μ.

Original Images

Cite This Page:
Potapova, M. (2010). Psammothidium chlidanos. In Diatoms of the United States. Retrieved May 22, 2018, from

Species: Psammothidium chlidanos

Contributor: Marina Potapova

Reviewer: Sarah Spaulding


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.

Lange-Bertalot, H. (1999). Neue Kombinationen von taxa aus Achnanthes Bory (sensu lato). Iconographia Diatomologica 6: 276-289.

Links & ID's

Index Nominum Algarum (INA)

California Academy of Sciences (CAS)

Psammothidium chlidanos CAS

NCBI Genbank Taxonomy

Achnanthes chlidanos NCBI

North American Diatom Ecological Database (NADED)

NADED ID: 186011

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

Psammothidium chlidanos

EMAP Response Plots

Psammothidium chlidanos

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.