(Gregory) Kociolek and Stoermer 1987 Category: Asymmetrical biraphid
BASIONYM: Cymbella sinuata Gregory 1856
Contributor: Marina Potapova - May 2009
Length Range: 8-22 µm
Width Range: 3.1-5.5 µm
Striae in 10 µm: 10–16
Valves are linear-lanceolate with subcapitate ends, dorsiventral with convex dorsal side and more or less straight ventral side, 3.1-5.5 µm wide, 8-22 µm long. Ventral side of the valve has a pronounced medial expansion. Striae are biseriate, consisting of two rows of poroid areolae, 10-16 in 10 µm in the middle of the dorsal side. The central area occupies an expansion in the middle of the ventral side and has one isolated stigma. The raphe is straight, with the terminal raphe fissures curved to the ventral side. Apical pore fields occur on the ventral mantles.
The valve symmetry is as in a cymbelloid diatom, but presence of the apical pore fields and other characters place this genus within gomphonemoid diatoms.
Basionym: Cymbella sinuata
Author: Gregory 1856
Length Range: 20-30 µm
Striae in 10 µm: 8
It is narrow, slightly arcuate, with rather square, slightly expanding apices. On the generally concave side are three rounded but gentle prominences; the cnetral one considerable, the lateral ones, which are near the ends, very slight. Striae conspicuous, sub-distant, about 20 in .001, not reaching, or hardly reaching, the median line, which seems to be, as in the known Cymbellae, a little nearer the ventral surface. there is in most cases a blank space round the central nodule. Length from .008 to .0012 inch. The characters of this species are very constant. It varies somewhat in size, and a little also in the form of the apices, which are in some less square than in others.
Gregory, W. (1856). Notice of some new species of British Fresh-water Diatomaceae. Quarterly Journal of Microscopical Science, new series, London 4:1-14, pl. I.
Kociolek, J.P. and Stoermer, E.F. (1987). Ultrastructure of Cymbella sinuata and its allies (Bacillariophyceae), and their transfer to Reimeria, gen. nov. Systematic Botany 12(4):451-459. http://www.jstor.org/stable/2418882
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.