Grunow in Van Heurck 1880 Category: Asymmetrical biraphid
BASIONYM: Gomphonema mexicanum Grunow in Van Heurck 1880
Contributor: Pat Kociolek - March 2011
Length Range: 26-55 µm
Width Range: 9-13 µm
Striae in 10 µm: 9-11
Valves are elliptical-clavate with the headpole produced slightly and broadly rostrate and footpole rounded. Axial area is straight, expanded slightly due to a shortened stria on either side of the central area. A single stigma is present in the central area. The internal opening of the stigma opening is offset from the external opening. The raphe is lateral and weakly undulate. External proximal raphe ends are dilated slightly. Striae are punctate, parallel to radiate, number 9-11 in 10 µm and are strongly radiate at the footpole. An apical pore field is present at the footpole. Septa and pseudosepta are present at the poles.
There is no evidence to support Krammer and Lange-Bertalot”s (1986) inclusion of this species within “Gomphonema clavatum Ehrenberg” (compare the forms in plate 163, Fig. 9 for G. mexicanum in that reference).
Basionym: Gomphonema mexicanum
Author: Grunow in Van Heurck 1880
Length Range: µm
Striae in 10 µm:
Patrick, R.M. and Reimer, C.W. (1975). The Diatoms of the United States, exclusive of Alaska and Hawaii, V. 2. Monographs of the Academy of Natural Sciences of Philadelphia 13.
NADED ID: 37163
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.