(Hilse) Cleve 1891 Category: Symmetrical biraphid
BASIONYM: Pinnularia ovalis Hilse in Rabenhorst 1861
REPORTED AS: Diploneis ovalis (Hustedt 1930, p. 249, fig. 390)
Contributor: Loren Bahls - January 2014
Length Range: 33-59 µm
Width Range: 20.7-32.6 µm
Striae in 10 µm: 12-14
Valves are elliptic to oval with broad, round apices. The longitudinal canals are narrow, the width of one to three areolae, and follow the margin of the axial and central areas. The axial area is occupied almost completely by a broad raphe. The central area is large and orbicular, 4.9-8.5 µm wide. Striae are uniseriate and radiate throughout. Areolae are large, blocky and number 16-20 in 10 µm.
Diploneis ovalis is less common than D. krammeri, which is often misidentified as D. ovalis.
Basionym: Pinnularia ovalis
Author: Hilse in Rabenhorst 1861
Length Range: µm
Striae in 10 µm:
Cleve, P.T. (1891). The Diatoms of Finland. Actas Societas Pro Fauna et Flora Fennica 8 (2): 1-68.
Hustedt, F. (1930). Bacillariophyta (Diatomeae). In: Die Subwasser Flora Mitteleuropas. (A. Pascher, ed.),10, Gustav Fischer, Jena. 468 pp.
Lange-Bertalot, H. and Reichardt, E. (2000). Diploneis ovalis sensu stricto und Diploneis krammeri nov. spec. Revision des aktuellen Konzepts von Diploneis ovalis (Hilse) Cleve. Appendix, pp. 650-669 in Rumrich, U., Lange-Bertalot, H. and Rumrich, M. (2000). Diatoms of the Andes from Venezuela to Patagonia/Tierra del Fuego and two additional contributions. Lange-Bertalot, H. (ed.), Iconographia Diatomologica. Annotated Diatom Micrographs. Vol. 9. Phytogeography-Diversity-Taxonomy. Koeltz Scientific Books, Königstein, Germany, 9:673 pp.
Rabenhorst, L.G. (1861). Die Algen Europa’s Forsetzung der algen Sachsens, resp. Mittel-Europa’s. Decades 3-4, numbers 1021-1040. Dresden.
Lange-Bertalot and Reichardt (in Rumrich et al. 2000) report that D. ovalis prefers “weakly buffered, electrolyte-poor, weakly acidic waters”. It is less common in the Northwest United States than D. krammeri, with which it is often confused. The specimens of D. ovalis shown on the identification page are from Lake Caroline, a small lake in the Cascade Mountains of Washington (photo below).
Lake Caroline, Chelan County, Washington: home of Diploneis ovalis.
Credit/Source: Ryan Davis, Adventurers and Scientists for Conservation
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.
Previously, the page for Diploneis ovalis included images for a taxon that is similar to Diploneis krammeri. The concept presented here is now in alignment with D. ovalis. - L. Bahls, S. Spaulding