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Psammothidium subatomoides

(Hust.) Bukht. and Round 1996      Category: Monoraphid
BASIONYM: Navicula subatomoides Hust. in Schmidt et al. 1936
SYNONYM(S): Achnanthes subatomoides (Hust.) Lange-Bert. and Archibald in Krammer and Lange-Bert. | Achnanthidium subatomoides (Hust.) Monnier, Lange-Bert. and Ector in Monnier et al. 

Psammothidium semiapertum


Pseudofallacia monoculata

LM scalebar = 10 µm = 80 pixels.


Contributor: Marina Potapova - May 2009
Length Range: 6-11 µm
Width Range: 3.2-6.0 µm
Striae in 10 µm: 30-40


Valves are elliptical, 3.2-6.0 µm wide and 5.5-11 µm long. On the raphe valve, the axial area widens in the central portion of the valve, forming a “bow-tie” shaped central area. The raphe is straight, without terminal raphe fissures. Externally, the proximal raphe ends are expanded. Internally, the proximal raphe ends curve to opposite sides. On the rapheless valve, the axial area is narrow and linear, with a central expansion forming a rhomboidal or ‘bow-tie” shaped central area. Striae are radiate and number 30-40 in 10 µm. Both external and internal openings of the areolae are transapically elongated. One row of areolae is positioned on the valve margin.

Original Description

Basionym: Navicula subatomoides
Author: Hust. in Schmidt et al. 1936
Length Range: µm
Striae in 10 µm:

Original Description

Kann wegen der wesentlich zarteren Struktur nicht mehr mit Taf. 403, Fig. 51-53 verbunden werden.

Original Images

Original text and images reproduced with permission by Koeltz Scientific.

Cite This Page:
Potapova, M. (2009). Psammothidium subatomoides. In Diatoms of the United States. Retrieved May 22, 2018, from

Species: Psammothidium subatomoides

Contributor: Marina Potapova

Reviewer: Sarah Spaulding


Bukhtiyarova, L. and Round, F. E. (1996). Revision of the genus Achnanthes sensu lato. Psammothidium, a new genus based on Achnanthidium marginulatum. Diatom Research 11: 1-30. 10.1080/0269249X.1996.9705361

Krammer, K. and Lange-Bertalot, H. (1985). Naviculaceae Neue und wenig bekannte Taxa, neue Kombinationen und Synonyme sowie Bemerkungen zu einigen Gattungen. Bibliotheca Diatomologica 9:5-230, 43 pls.

Monnier, O., Lange-Bertalot, H., Hoffmann, L. and Ector, L. (2007). The genera Achnanthidium Kützing and Psammothidium Bukhtiyarova et Round in the family Achnanthidiaceae (Bacillariophyceae): a reappraisal of the differential criteria. Cryptogamie, Algologie 28:1 41-158.

Schmidt, A. (-). (1874-1959). Atlas der Diatomaceen-Kunde, von Adolf Schmidt, continued by Martin Schmidt, Friedrich Fricke, Heinrich Heiden, Otto Muller, Friedrich Hustedt. Reprint 1984, Koeltz Scientific Books, Konigstein, 480 plates.

Links & ID's

Index Nominum Algarum (INA)

Original INA
Transfer INA

California Academy of Sciences (CAS)

Psammothidium subatomoides CAS

NCBI Genbank Taxonomy

Psammothidium subatomoides NCBI

North American Diatom Ecological Database (NADED)

NADED ID: 186008

Autecology Discussion

Freshwater, oligotraphentic species

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 subatomoides

EMAP Response Plots

Psammothidium subatomoides

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.