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Navicula rhynchotella

Lange-Bert. 1993      Category: Symmetrical biraphid

REPORTED AS: Navicula rhyncocephala (Patrick & Reimer 1966) 

Navicula rhynchocephala


Navicula rostellata

LM scalebar = 10 µm = 40 pixels.


Contributor: Loren Bahls - November 2011
Length Range: 47-54 µm
Width Range: 12.1-13.5 µm
Striae in 10 µm: 10-12


Valves are broadly lanceolate to elliptic-lanceolate. Ends are narrow, abruptly protracted and subcapitate to capitate. The axial area is narrow and nearly linear. The central area is large and transversely elliptical. Raphe branches are weakly lateral. The proximal raphe ends are expanded and deflected slightly to the primary side. Striae are radiate and more widely spaced about the central area, becoming parallel and finally convergent at the poles. Areolae are coarse and number 20-23 in 10 µm.

Note that the specimen illustrated as N. rhynchocephala in Patrick & Reimer (1966) corresponds to the type of N. rhynchotella.

Original Description

Author: Lange-Bert. 1993
Length Range: 35-60 µm
Width Range: 13-14 µm
Striae in 10 µm: 8-11

Original Description

Valvae late ellipticae finibus distincte rostratis, 35-60(80) microns longae, semper magis quam 9 microns, i.e. 10-16 plerumque 13-14 microns latae. Areae et positus et numerus striarum (8-11/10 microns) et numerus lineolarum (20-25/10 microns) N. rhynchocephala similes. Structurae ultramicroscopicae significantes et differentes se praestant in imaginibus figurarum no. 63: 1-6. Comparatio photographica meliorem facet quam per multa vocabula.

Original Images

Cite This Page:
Bahls, L. (2011). Navicula rhynchotella. In Diatoms of the United States. Retrieved May 26, 2018, from

Species: Navicula rhynchotella

Contributor: Loren Bahls

Reviewer: Marina Potapova


Lange-Bertalot, H. (1993). 85 Neue taxa und uber 100 weitere neu definierte Taxa erganzend zur Subwasserflora von Mittleuropa. Bibliotheca Diatomologica 27, 454 p. Cramer, Berlin, Stuttgart.

Lange-Bertalot, H. (2001). Navicula sensu stricto, 10 genera separated from Navicula sensu lato, Frustulia. Diatoms of Europe 2: 1-526.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Navicula rhynchotella CAS

NCBI Genbank Taxonomy

Navicula rhynchotella NCBI

North American Diatom Ecological Database (NADED)


Autecology Discussion

There are eight records of Navicula rhynchotella in the Montana Diatom Collection, all of them from the Poplar River or tributaries of the Poplar River in extreme northeastern Montana (near the border with Saskatchewan), where the species is uncommon. The Poplar River and tributaries are freshwater streams but with elevated levels of dissolved solids. Common diatom associates of Navicula rhynchotella in these waters include Planothidium engelbrechtii, Nitzschia commutatoides, Navicula cryptocephaloides, Navicula integra, Craticula riparia, Placoneis placentula, Navicula slesvicensis, Craticula buderi, Placoneis clementis, Navicula associata, Nitzschia bulnheimiana, Navicula amphiceropsis, and Luticola nivalis. Lange-Bertalot (2001) reports Navicula rhynchotella as widespread in Europe, in brackish waters along the coasts, in electrolyte-rich inland waters, and rarely in well buffered, alkaline freshwaters with average electrolyte content (e.g., the Rhine River).


Poplar River, Montana: home of Navicula rhynchotella.

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

Navicula rhynchotella

EMAP Response Plots

Navicula rhynchotella

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.