Kociolek and Stoermer 1988 Category: Asymmetrical biraphid
BASIONYM: Gomphoneis herculeana var. lowei Kociolek and Stoermer 1988
Contributor: Pat Kociolek - January 2011
Length Range: 47-140 µm
Width Range: 16-25 µm
Striae in 10 µm: 8-12 in the central portion of the valve, 12-14 at the headpole, 13-16 at the footpole
Valves are broadly trullate, with broadly rounded apices. Initial valves are unknown. The axial area is narrow, straight, forming a relatively small, irregularly rounded central area. A single stigma is present in the central area. The raphe is lateral, weakly undulate and with small external proximal ends. The raphe has highly recurved internal proximal ends. Striae are distinctly biseriate, with the areolae arranged alternately. From the central nodule to the head-pole striae are radiate. From the central nodule to the foot pole striae are radiate, become parallel and near the footpole become strongly radiate. Longitudinal lines are positioned approximately one-half the way between the axial area and margin. The apical pore fields are distinctly bi-lobed but reduced in size.
Distribution: To date this species has been confirmed from relatively unimpacted lakes and rivers in the Pacific Northwest.
Basionym: Gomphoneis herculeana var. lowei
Author: Kociolek and Stoermer 1988
Length Range: µm
Striae in 10 µm:
Kociolek, J.P. and Stoermer, E.F. (1988). Taxonomy, ultrastructure and distribution of Gomphoneis herculeana, G. eriense and closely related species (Naviculales: Gomphonemataceae). Proc. Acad. Nat. Sci. Phil. 140: 24-97. http://www.jstor.org/stable/4064935
NADED ID: 36005
This species confirmed in relatively unimpacted lakes and rivers of the Pacific Northwest. The images shown for this taxon are from the Metolius River, Oregon.
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.