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Navicula libonensis

Schoeman 1969      Category: Symmetrical biraphid

Navicula leptostriata


Navicula longicephala

LM scalebar = 10 µm = 80 pixels.


Contributor: Marina Potapova - February 2011
Length Range: 27-35 µm
Width Range: 5.9-7.0 µm
Striae in 10 µm: 12-13


Valves are lanceolate with rounded or very slightly drawn-out ends. The axial area is narrow and linear. The central area is transversely elliptical or irregular-rectangular, often slightly asymmetrical. The proximal raphe ends are straight, slightly expanded. Terminal raphe fissures are hooked towards the secondary side. The lineolate striae are radiate, becoming convergent at the valve apices, 12-13 in 10 µm. The areolae are easily observed under LM, 28-32 in 10 µm.

Note that this concept of Navicula libonenesis follows Lange-Bertalot (2001), but the type material of this species have not been photographed. Therefore it is not clear at present whether North American, European, and South African populations represent the same species.

Original Description

Author: Schoeman 1970
Length Range: 24-32 µm
Width Range: 5-7 µm
Striae in 10 µm: 11-14

Original Description

The valves are lanceolate with regularly rounded ends which are not produced, 24-32 μ long and 5-7 μ wide. The raphe is straight and filiform bending sharply near the poles towards the same side of the valvar margin; the terminal fissures were observed in only a few cases and appeared to run alongside the valvar margin, thus bending towards the valvar poles; the central poles are small but definite, fairly close together, The axial area is narrow and linear with definite polar areas, and widens into a central area due to the regular or irregular shortening of the central striae. The transapical striae are radial becoming parallel or convergent near the poles, 11-14 in 10 μ (13-14 in 10 μ near the poles of the valve), clearly lineolate. Lineolae form longitudinal striae, 28-30 in 10 μ.

Original Images

Cite This Page:
Potapova, M. (2011). Navicula libonensis. In Diatoms of the United States. Retrieved May 26, 2018, from

Species: Navicula libonensis

Contributor: Marina Potapova

Reviewer: Pat Kociolek


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

Schoeman, F.R. (1969). Diatoms from the Orange Free State (South Africa) and Lesotho. No. 2. Revista de Biologia 7(1-2):35-74,.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Navicula libonensis CAS

North American Diatom Ecological Database (NADED)

NADED ID: 46542

Autecology Discussion

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 libonensis

EMAP Response Plots

Navicula libonensis

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.