Sovereign 1958 Category: Symmetrical biraphid
BASIONYM: Navicula aurora Sovereign 1958
Contributor: Loren Bahls - November 2011
Length Range: 65-130 µm
Width Range: 18-28 µm
Striae in 10 µm: 7-9
Valves are elliptic-lanceolate with broadly rounded and slightly protracted ends. Axial area is narrow, linear, about twice the width of the raphe. Central area is broad and transversely rectangular with rounded corners and irregular borders formed by shortened striae of various lengths. Raphe is lateral, becoming filiform near the proximal ends, which are triangular in shape and deflected slightly toward the secondary side. Striae are mostly radiate, becoming parallel and finally somewhat convergent near the valve ends. Areolae are fine, 26-28 in 10 µm. Voigt discontinuities are clearly evident on the secondary side.
Basionym: Navicula aurora
Author: Sovereign 1958
Length Range: 59-118 µm
Width Range: 15-26 µm
Striae in 10 µm: 6.3-7.5
Valvae elliptico vel lineari-lanceolatae apicibus obtusis late rotundatis, subprotractis, 59-118 µ longae, 15-26 µ latae; raphe directa fissuris terminalibus longis in eandem partem flexis, area axialis distincta, linearis, modice lata, area centralis lata, transapicaliter elliptica; striae transapicales 6.3 ad 7.5 in 10 µ, radiantes, prope apices ad lineam mediam perpendiculares, distincte lineolatae.
Patrick, R.M. and Reimer, C.W. (1966). The Diatoms of the United States exclusive of Alaska and Hawaii, V. 1. Monographs of the Academy of Natural Sciences of Philadelphia 13.
Sovereign, H.E. (1958). The diatoms of Crater Lake, Oregon. Transactions of the American Microscopical Society 77(2):96-134.
Navicula aurora has been recorded in the benthos of streams and lakes, primarily in the Pacific Northwest. This taxon prefers cool and somewhat alkaline waters with low conductivity and low to moderate concentrations of nutrients. Common associates of Navicula aurora in the Northwest include Diploneis ovalis, Nitzschia innominata, Planothidium peragalli, Planothidium daui, Cavinula cocconeiformis, Geissleria schoenfeldii, Achnanthes oblongella, Planothidium rostratum, Planothidium lanceolatoides, and Achnanthidium rivulare.
Our Lake, Teton County, Montana: home of Navicula aurora
Credit/Source: Loren Bahls
Abundance-weighted mean values for selected water quality variables measured concurrently with the collection of samples containing Navicula aurora.
Credit/Source: Montana Diatom Database
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.