Contributor: Loren Bahls - August 2013
Length Range: 22-43 µm
Width Range: 5.0-7.6 µm
Striae in 10 µm: 10-15
Valves are dorsiventral. The dorsal margin is moderately arched, somewhat convex to nearly flat (or weakly concave in larger specimens) and subtly biundulate. The ventral margin is weakly concave to nearly flat. Apices are rostrate, broadly rounded and distinctly set off from the high dorsal ‘shoulders’. Terminal raphe ends are positioned on the ventral margin, some distance from the apices. Striae are weakly radiate, composed of fine areolae and nearly evenly spaced, although an occasional short stria may be interspersed along the dorsal margin. Under the SEM, the areolae can be seen to lie in separate depressions and number about 30 in 10 µm. Internally, the raphe fissure terminates in a raised helictoglossa.
Basionym: Eunotia sudetica
Author: O. Müller 1898
Length Range: µm
Striae in 10 µm:
Lange-Bertalot, H., Bak, M., Witkowski, A. and Tagliaventi, N. (2011). Eunotia and some related genera. Diatoms of the European Inland Waters and Comparable Habitats. 6: 747 pp.
Müller, O. (1898). Bacillariales aus den Hochseen des Riesengebirges. Forschungsber. Biol. Stat. Plön 6: 1-40.
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.
Siver, P.A., Hamilton, P.B., Stachura-Suchoples, K. and Kociolek, J.P. (2005). Diatoms of North America. The Freshwater Flora of Cape Cod. Iconographia Diatomologica 14: 1-463.
Patrick and Reimer (1966) report Eunotia sudetica from acid to circumneutral waters in Pennsylvania and the southeastern United States. Siver et al. (2005) report this species from two acidic ponds on Cape Cod, Massachusetts. Lange-Bertalot et al. (2011) report that E. sudetica prefers small, running waters or wet bryophyte habitats. The one record of this species in the Montana Diatom Collection is from a lake high in the Sierra Nevada Mountains of California (photo below).
Evolution Lake at an elevation of 3,313 m in the Sierra Nevada Range of central California, home of Eunotia sudetica.