Hantzsch 1860 Category: Nitzschioid
BASIONYM: Nitzschia clausii Hantzsch 1860
SYNONYM(S): Nitzschia sigma var. clausii (Hantzsch) Grunow
Contributor: Pat Kociolek - September 2011
Length Range: 20-68 µm
Width Range: 3.0-5.0 µm
Striae in 10 µm:
In girdle view, the frustules are distinctly sigmoid. Valves are linear and slightly concave at the center. The apices are distinctly rounded, capitate or rostrate and bent to form a sigmoid valve shape. The striae are very fine. The keeled raphe is distinct, with robust fibulae. Fibula density is 10-13 in 10 µm.
Krammer and Lange-Bertalot (1988, Plate 19, Figs 1-6A) illustrate longer specimens of this species (e.g. Fig. 5) that are narrower than the shorter specimens (e.g. Fig. 1), suggesting that more than one taxon might be included in their concept of the species.
Basionym: Nitzschia clausii
Author: Hantzsch 1860
Length Range: µm
Striae in 10 µm:
Hantzsch, C. A. (1860). Neue Bacillarien: Nitzschia vivax var. elongata, Cymatopleura nobilis. Hedwigia 2(7):40, pl. 6.
Krammer, K. and Lange-Bertalot, H. (1988). Bacillariophyceae. 2. Teil: Bacillariaceae, Epithemiaceae, Surirellaceae. In: Ettl, H., J. Gerloff, H. Heynig and D. Mollenhauer (eds.) Susswasserflora von Mitteleuropa, Band 2/2. Gustav Fisher Verlag, Jena.
Rabenhorst, L. (1860). Die Algen Sachsens resp. Mittel-Europa’s. Decas 95-96. no. 943-953 etc. .
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.
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.