(Kützing) Grunow in Schmidt 1875 Category: Asymmetrical biraphid
BASIONYM: Cymbella pediculus Kützing 1844
SYNONYM(S): Amphora ovalis var. pediculus (Kützing) Van Heurck 1885
Valves moderately dorsiventral, semi-elliptical becoming semi-circular in small taxa. Dorsal margin arched, ventral margin straight to slightly concave. Valve ends rounded, sometimes with a slight ventral deflection. Axial area very narrow with the raphe ledge poorly developed. Raphe straight with proximal raphe ends straight and distal raphe ends dorsally deflected. Dorsal and ventral fascia distinct and extending to valve margins. Dorsal striae parallel in central area, becoming weakly radiate at the apices. Dorsal striae distinctly punctate with 2-3 rows of areolae near the central area. Ventral striae composed of a single row of areolae, radiate near the central area, becoming convergent at the apices.
Schoeman and Archibald (1978) in an examination of A. perpusilla based on slide BM 26315 concluded that A. perpusilla was identical to their concept of A. pediculus (the concept adopted here), and therefor will be considered synonyms. Due to their small size the light microscope may be inadequate to describe the diversity of this group, further revision is probably needed (see Lee & Round (1989), Krammer (1980) and Schoeman & Archibald (1978) for a more thorough discussion).
Basionym: Cymbella pediculus
Author: Kützing 1844
Length Range: µm
Striae in 10 µm:
Krammer, K. (1980). Morphologic and taxonomic investigations of some freshwater species of the diatom genus Amphora Ehr. Bacillaria 3:197-225.
Lee, K. and Round, F.E. (1989). Studies on freshwater Amphora species. III. Amphora pediculus (Kutz.) Grun. and some possibly related forms. Diatom Research 4 (1): 79-87.
Schmidt, A. (-). (1874-1959). Atlas der Diatomaceen-Kunde, von Adolf Schmidt, continued by Martin Schmidt, Friedrich Fricke, Heinrich Heiden, Otto Muller, Friedrich Hustedt. Reprint 1984, Koeltz Scientific Books, Konigstein, 480 plates.
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.