Encyonopsis cesatii

(Rabenh.) Krammer 1997      Category: Asymmetrical biraphid
BASIONYM: Navicula cesatii Rabenh. 1853

REPORTED AS: Cymbella cesatii (Krammer and Lange-Bertalot 1986, p. 325 [in part], pl. 134, figs. 11, 12) | Cymbella cesatii (Patrick and Reimer 1975, p. 21 [in part], pl. 3, fig. 2) 

Encyonopsis cesatiformis


Encyonopsis czarneckii

LM scalebar = 10 µm = 80 pixels.


Contributor: Loren Bahls - May 2013
Length Range: 22-39 µm
Width Range: 4.6-6.0 µm
Striae in 10 µm: 16-19 at the valve center, 21-22 near the apices


Valves are narrowly lanceolate and nearly symmetric with respect to the apical axis. Apices are subrostrate and deflected weakly toward the ventral side. The axial area is narrow. The central area is small and asymmetric, formed by 1-3 shortened striae on the ventral side. The raphe is weakly lateral. Proximal raphe ends are deflected toward the dorsal side. Terminal raphe ends are hooked toward the ventral side. Striae are radiate throughout. Areolae are very fine and difficult to resolve in LM.

The morphological range of E. cesatii presented follows the lectotype designated by Krammer (1997, p. 152, Tafel 182, figs. 1-9) and illustrated below. Note that both Krammer and Lange-Bertalot (1986) and Patrick and Reimer illustrate a broader range of varieties and species within E. cesatii (for example, E. stafsholtii and varities of E. cesatii) in their publications.

Original Description

Basionym: Navicula cesatii
Author: Rabenh. 1853
Length Range: 20-41 µm
Width Range: 5.4-6.0 µm
Striae in 10 µm: 18-19

Original Description

  1. N. Cesatii Rabenh. (T. VI F. 89) Fast wie N. aponina, aber weit schlanker und (2-2.5)/100 Mm. lang; die Nebenseiten zwar genau linealisch, aber immer breiter und an den abgerundet. Im Piedmonteschen.

Original Images

Cite This Page:
Bahls, L. (2013). Encyonopsis cesatii. In Diatoms of the United States. Retrieved April 26, 2018, from http://westerndiatoms.colorado.edu/taxa/species/encyonopsis_cesatii

Species: Encyonopsis cesatii

Contributor: Loren Bahls

Reviewer: Pat Kociolek


Bahls, L. (2013). Encyonopsis from western North America: 31 species from Alberta, Idaho, Montana, Oregon, South Dakota, and Washington, including 17 species described as new. Northwest Diatoms, Volume 5. The Montana Diatom Collection, Helena, 46 pp.

Krammer, K. (1997). Die cymbelloiden Diatomeen. Eine Monographie der weltweit bekannten Taxa. Teil 2. Encyonema part., Encyonopsis and Cymbellopsis. Bibliotheca Diatomologica 37:1-469.

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.

Rabenhorst, L. (1853). Die Süßwasser-Diatomaceen (Bacillarien) für Freunde der Mikroskopie. Leipzig, 72 pp.

Links & ID's

Index Nominum Algarum (INA)

Transfer INA

California Academy of Sciences (CAS)

Encyonopsis cesatii CAS

North American Diatom Ecological Database (NADED)

NADED ID: 203001

Autecology Discussion

Encyonopsis cesatii is common in small headwater lakes, ponds and springs in the northern Rocky Mountains, where it is often found among mosses. Here it prefers cold, circumneutral waters with low concentrations of nutrients and dissolved solids. In these habitats it is often found in association with Encyonopsis falaisensis. Patrick & Reimer (1975) report it from the New England states and the Great Lakes states. Krammer & Lange-Bertalot (1986) report it as a northern-alpine species and common in the Alps and Finland.


Kootenai Pond, Glacier National Park, Montana: home of Encyonopsis cesatii and Encyonopsis falaisensis.

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

Encyonopsis cesatii

EMAP Response Plots

Encyonopsis cesatii

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.