(Hustedt) Mann & Stickle in Round, Crawford & Mann 1990 Category: Symmetrical biraphid
BASIONYM: Navicula pseudoscutiformis Hustedt in Pascher 1930
Valves are nearly round. Areolae are approximately 36 in 10 μm. The axial area is narrow and linear and extends onto the valve margins at the apices; the central area is small and nearly indistinguishable from the axial area. The raphe is filiform with slightly expanded central raphe ends. The striae are punctate and strongly radiate. Striae are incomplete in the central valve, that is, several are short and do not extend from the central area to the valve margin. The stria density increases towards the apices. The external openings of the areolae are round. Internally, the areolae are elongated. Internally, the raphe slit is narrow at proximal and terminal ends. The helictoglossae are reduced.
Basionym: Navicula pseudoscutiformis
Author: Hustedt in Pascher 1930
Length Range: 9-15 µm
Width Range: 7-13 µm
Striae in 10 µm: 24
Schalen breit-elliptisch, fast kreisförmig, mit breit gerundeten Polen, 9-15 µ lang, 7-13 breit. Axialarea eng, um den Mittelknoten wenig erweitert. Zentralporen der Raphe entfernt gestellt. Transapikalstreifen durchweg radial, zart, etwa 24 in 10 µ, in der Mitte von ungleicher Länge, zart punktiert.
Hustedt, F. (1930). Bacillariophyta (Diatomeae). In: Die Subwasser Flora Mitteleuropas. (A. Pascher, ed.),10, Gustav Fischer, Jena. 468 pp.
Round, F.E., Crawford, R.M. and Mann, D.G. (1990). The Diatoms. Biology and Morphology of the Genera. Cambridge University Press, Cambridge, 747 pp.
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.