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Plagiotropis lepidoptera var. proboscidea

(Cleve) Reimer in R.M.Patrick and Reimer 1975      Category: Symmetrical biraphid
BASIONYM: Tropidoneis lepidoptera var. proboscidea Cleve 1894

REPORTED AS: Tropidoneis lepidoptera var. javanica (Hustedt 1938) 

Plagiotropis arizonica


Planothidium abbreviatum

LM scalebar = 10 µm = 20 pixels.


Contributor: Loren Bahls - February 2012
Length Range: 73-110 µm
Width Range: 17.1-20.4 µm
Striae in 10 µm: 17-19


Valves are lanceolate with an arched valve face. The valve face has longitudinal folds and apiculate apices. The narrow axial area and raphe are positioned on the apex of a raised keel that runs along the apical axis. The central area is asymmetric and about one-half the width of the valve. The raphe is filiform with simple proximal and distal ends. Proximal raphe ends are straight and positioned close to one another. Striae are parallel at the center, becoming increasingly radiate towards the apices. The striae may appear wavy because of valve contours. Areolae are difficult to resolve in LM and number 26-30 in 10 µm.

Original Description

Basionym: Tropidoneis lepidoptera var. proboscidea
Author: Cleve 1894
Length Range: 75 µm
Width Range: 18 µm
Striae in 10 µm: 16-18

Original Description

Original Images

Cite This Page:
Bahls, L. (2012). Plagiotropis lepidoptera. In Diatoms of the United States. Retrieved May 23, 2018, from

Species: Plagiotropis lepidoptera

Contributor: Loren Bahls

Reviewer: Rex Lowe


Cleve, P.T. (1894). Synopsis of the Naviculoid Diatoms, Part I. Kongliga Svenska-Vetenskaps Akademiens Handlingar 26(2):1-194, 5 pls.

Czarnecki, D.B. and Wee, J.L. (1984). The frustular morphology of the diatom Plagiotropis lepidoptera var. proboscidea. Transactions of the American Microscopical Society 103 (1): 74-83.

Hustedt, F. (1938). Systematische und ökologische Untersuchungen über die Diatomeen-Flora von Java, Bali und Sumatra nach dem Material der Deutschen Limnologischen Sunda-Expedition. I. Systematischer Teil. Archiv für Hydrobiologie, Aus Supplement-Band XV: 131-177, 187-295, 393-506.

Paddock, T.B.B. (1988). Plagiotropis Pfitzer and Tropidoneis Cleve, a summary account. Bibliotheca Diatomologica (H. Lange-Bertalot, ed.). Vol. 16. J. Cramer, Berlin, 152 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.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Plagiotropis lepidoptera var. proboscidea CAS

North American Diatom Ecological Database (NADED)

NADED ID: 53002

Autecology Discussion

Plagiotropis lepidoptera var. proboscidea has been found in 37 samples collected from streams on the Northwestern Great Plains. The mean pH of these waters is 8.3 and the mean specific conductance is 4389 µS/cm. These waters have elevated concentrations of sodium (mean = 613 mg/L), sulfate (mean = 1307 mg/L), iron (mean = 1560 µg/L), and manganese (mean = 1944 µg/L). Common diatom associates include Navicula namibica, Planothidium engelbrechtii, Bacillaria paradoxa, Navicula peregrina, Staurophora brantii, Nitzschia siliqua, Entomoneis alata, and Tryblionella compressa. Patrick and Reimer (1975) report this taxon as widespread in the United States in alkaline streams. It was described from material collected in Cameroun, Africa (Cleve 1894).

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

Plagiotropis lepidoptera var. proboscidea

EMAP Response Plots

Plagiotropis lepidoptera var. proboscidea

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.