Visit us at

Diatoms of the United States is now known as Diatoms of North America.
This site has been redesigned and updated, and will be closing soon.

Hannaea arcus

(Ehrenb.) R.M.Patrick 1966      Category: Araphid
BASIONYM: Navicula arcus Ehrenb. 1836
SYNONYM(S): Ceratoneis arcus (Ehrenb.) Kütz. 

Halamphora veneta


Hannaea superiorensis

LM scalebar = 10 µm = 40 pixels.


Contributor: Pat Kociolek - December 2010
Length Range: 15-80 µm
Width Range: 4-7 µm
Striae in 10 µm: 13-14


Valves are asymmetric to the apical axis; the dorsal margin is highly arched and convex, while the ventral margin is concave. A central, unilateral swelling is present on the ventral margin. Ghost striae may be present in the central swelling. Valve apices are capitate to attenuate. A narrow, distinct central sternum is present. One to two rimoportulae are present at the valve apices.

Original Description

Basionym: Navicula arcus
Author: Ehrenb. 1836
Length Range: µm
Striae in 10 µm:

Original Description

Original Images

Cite This Page:
Kociolek, P. (2010). Hannaea arcus. In Diatoms of the United States. Retrieved May 25, 2018, from

Species: Hannaea arcus

Contributor: Pat Kociolek

Reviewer: Sarah Spaulding


Bixby, R.J. and Jahn, R. (2005). Hannaea arcus (Ehrenberg) R.M. Patrick: lectotypification and nomenclatural history. Diatom Research 20: 210-226. 10.1080/0269249X.2005.9705632

Bixby, R.J., Edlund, M.B., and Stoermer, E.F. (2005). Hannaea superiorensis sp. nov., an endemic diatom from the Laurentian Great Lakes. Diatom Research 20: 227–240. 10.1080/0269249X.2005.9705633

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. (1966). The Diatoms of the United States exclusive of Alaska and Hawaii, V. 1. Monographs of the Academy of Natural Sciences of Philadelphia 13.

Links & ID's

Index Nominum Algarum (INA)

Original INA
Transfer INA

California Academy of Sciences (CAS)

Hannaea arcus CAS

North American Diatom Ecological Database (NADED)

NADED ID: 39001

Autecology Discussion

Hannaea arcus is found in cool flowing water in mountainous regions across the US.

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

Hannaea arcus

EMAP Response Plots

Hannaea arcus

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.


- Citation correction

The transfer of Ceratoneis arcus (Ehrenberg) Kützing to Hannaea arcus Patrick 1961 was listed incorrectly as occurring in Patrick and Freese 1961. The transfer should appear as Hannea arcus Patrick (Patrick and Reimer 1966, pg. 132). - S. Spaulding