Entomoneis paludosa

(W.Sm.) Reimer 1975      Category: Asymmetrical biraphid
BASIONYM: Amphiprora paludosa W.Sm. 1853

REPORTED AS: Entomoneis paludosa var. subsalina (Krammer and Lange-Bertalot 1986) 

Entomoneis ornata


Entomoneis punctulata

LM scalebar = 10 µm = 40 pixels.


Contributor: Loren Bahls - February 2012
Length Range: 38-85 µm
Width Range: 19-31 (girdle view) µm
Striae in 10 µm: 20-26


Frustules almost always come to rest in girdle view, a view which is dominated by two highly arched bilobate keels, one on each valve. The keels are slightly torsioned so that the lobes are not all in focus at one time. Lobe margins are flattened in large specimens and more rounded in smaller specimens. Several girdle bands are present and form a crossing, sigmoid pattern that is most evident in small specimens. The junction line between the valve and the keel contains a single bulge, which is flattened and smoothly rounded in large specimens but more angular in smaller specimens. The junction line lacks prominent spots or thickened ribs. Striae on the valve face continue onto the keel without differentiation. Areolae within a stria on both the valve face and the keel are very fine and number approximately 30 in 10 µm.

Original Description

Basionym: Amphiprora paludosa
Author: W.Sm. 1853
Length Range: µm
Striae in 10 µm:

Original Description

Original Images

Cite This Page:
Bahls, L. (2012). Entomoneis paludosa. In Diatoms of the United States. Retrieved April 23, 2018, from http://westerndiatoms.colorado.edu/taxa/species/entomoneis_paludosa

Species: Entomoneis paludosa

Contributor: Loren Bahls

Reviewer: Rex Lowe


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.

Patrick, R.M. and Reimer, C.W. (1975). The Diatoms of the United States, exclusive of Alaska and Hawaii, V. 2. Monographs of the Academy of Natural Sciences of Philadelphia 13.

Smith, W. (1853). Synopsis of British Diatomaceae. John Van Voorst, London 1853. 89 pp., pls 1-31.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Entomoneis paludosa CAS

NCBI Genbank Taxonomy

Amphiprora paludosa NCBI
Entomoneis paludosa NCBI

North American Diatom Ecological Database (NADED)

NADED ID: 31001

Autecology Discussion

With 264 records in the Montana Diatom Collection, Entomoneis paludosa is the most frequently occurring species of this genus on the Northwestern Great Plains (Montana, North Dakota, South Dakota, Wyoming). The preferred habitat of this epipelic diatom is muddy streams with a mean pH of 8.6, a mean specific conductance of 3279 µS/cm, and elevated concentrations of sodium and sulfate. Frequent diatom associates of E. paludosa in these habitats are Cymbella pusilla, Nitzschia reversa, Pleurosigma delicatulum, Biremis circumtexta, Nitzschia filiformis, Navicula erifuga, Tabularia fasciculata, and Nitzschia aurariae. Patrick and Reimer (1975) report this species as widely distributed in the United States in waters with moderately high conductivity.


Little Dry Creek, Garfield County, Montana: home of Entomoneis paludosa.

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

Entomoneis paludosa

EMAP Response Plots

Entomoneis paludosa

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.