(Hustedt) Krammer 1997 Category: Asymmetrical biraphid
BASIONYM: Navicula descripta Hustedt 1943
SYNONYM(S): Cymbella descripta (Hustedt) Krammer and Lange-Bertalot 1985
REPORTED AS: Cymbella descripta (Krammer and Lange-Bertalot 1986, p. 327, figs. 135: 1-5)
Contributor: Loren Bahls - May 2013
Length Range: 26-30 µm
Width Range: 5.4-6.6 µm
Striae in 10 µm: 18-20 at valve center, 20-22 near the apices
Valves are linear-lanceolate with capitate apices and not or only slightly dorsiventral. The axial area is narrow and positioned along the valve midline. The central area is large, round, and nearly symmetric. The raphe is weakly lateral, becoming filiform near the proximal and distal ends. Proximal raphe ends are weakly expanded and deflected dorsally. Distal raphe ends are curved toward the ventral side. Striae are radiate throughout.
Basionym: Navicula descripta
Author: Hustedt 1943
Length Range: µm
Striae in 10 µm:
Bahls, L. (2013). Encyonopsis from western North America: 31 species from Alberta, Idaho, Montana, Oregon, South Dakota, and Washington, including 17 species described as new. Northwest Diatoms, Volume 5. The Montana Diatom Collection, Helena, 46 pp.
Hustedt, F. (1943). Die Diatomeenflora einiger Hochgebirgsseen der Landschaft Davos in den schweizer Alpen. Internationale Revue der gesamten Hydrobiologie und Hydrographie 43:124-197, 225-280.
Krammer, K. (1997). Die cymbelloiden Diatomeen. Eine Monographie der weltweit bekannten Taxa. Teil 2. Encyonema part., Encyonopsis and Cymbellopsis. Bibliotheca Diatomologica 37:1-469.
Simonsen, R. (1987). Atlas and Catalogue of the Diatom Types of Friedrich Hustedt. J. Cramer, Berlin & Stuttgart 1: 525 pp.
Encyonopsis descripta has been collected from a few remote lakes in the Northern Rockies. Here pH ranges from 7.0 to 8.2 and specific conductance from 64 to 250 µS/cm.
Lower Quartz Lake, Glacier National Park, Montana: home of Encyonopsis descripta.
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.