Kociolek and Kingston 1999 Category: Asymmetrical biraphid
BASIONYM: Gomphonema occidentale var. abbreviate M. Schmidt 1899
Contributor: Pat Kociolek - March 2011
Length Range: 19-45 µm
Width Range: 4-6 µm
Striae in 10 µm: 13-15
Valves are linear-lanceolate, clavate, headpole and footpole are rounded. Length is 19-45 µm, breadth is 4-6 µm. Axial area lanceolate with a linear-ellipitcal, slightly asymmetrical central area with the side opposite the stigma being larger than the side bearing the stigma. A single, large, distinct stigma is present at the central area. The raphe is lateral, weakly undulate to nearly straight, external proximal raphe ends terminate close to one another. External distal raphe ends are deflected onto the mantle, to the side of the valve opposite the stigma. Striae are parallel to radiate at the center and towards the headpole, more strongly radiate at the footpole, 13-15/10 µm. The apical pore field is bi-lobed and prominent.
Basionym: Gomphonema occidentale var. abbreviate
Author: M. Schmidt 1899
Length Range: µm
Striae in 10 µm:
Kociolek, J.P. and Kingston, J.C. (1999). Taxonomy, ultrastructure, and distribution of some gomphonemoid diatoms (Bacillariophyceae: Gomphonemataceae) from rivers in the United States. Canadian Journal of Botany 77: 686-705. 10.1139/cjb-77-5-686
Sampling for 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). Streams and rivers in 12 western states (Arizona, California, Colorado, Idaho, Montana, Nevada, North Dakota, Oregon, South Dakota, Utah, Washington and Wyoming). Over 1200 sites on 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.