Rabenhorst 1850 Category: Symmetrical biraphid
BASIONYM: Frustulia saxonica Rabenhorst 1853
Valves are generally rhomboid in shape, although valves at the small end of the size range are not strongly rhomboid. The apices are slightly constricted and narrowly rounded. The longitudinal ribs are slightly curved. Both the thickness of the ribs and size of the central nodule are variable in relation to valve size. The porte-crayon is relatively small. Striae are radiate the apices. Longitudinal striae are present, but may be disorganized at the valve center.
Basionym: Frustulia saxonica
Author: Rabenhorst 1853
Length Range: µm
Striae in 10 µm:
Lange-Bertalot, H. (2001). Navicula sensu stricto, 10 genera separated from Navicula sensu lato, Frustulia. Diatoms of Europe 2: 1-526.
Rabenhorst, L. (1848). Die Algen Sachsens. Resp. Mittel-Europa’s Gesammelt und herausgegeben von Dr. L. Rabenhorst, Dec. 1-100. No. 1-1000. Dresden. [Exsiccata, issued at various dates]. Dec. 1-100. No. 1-1000. Dresden. [Exsiccata, issued at various dates].
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.