(Grunow) Krammer 2003 Category: Asymmetrical biraphid
BASIONYM: Cymbella hybrida Grunow 1878
REPORTED AS: Cymbella hybrida (Patrick and Reimer 1975, p. 32, plate 4, fig. 10) | Cymbella hybrida (Krammer and Lange-Bertalot 1975, p. 337, figs 145: 1,3)
Contributor: Loren Bahls - September 2015
Length Range: 30-48 µm
Width Range: 6.9-8.1 µm
Striae in 10 µm: 12-14
Valves are linear and nearly symmetric on either side of the apical axis. Valve margins are parallel to slightly convex. Apices are subrostrate to subcapitate. The axial area is narrow and follows the valve midline. The central area is large and rounded, and reaches nearly to the valve margins. The raphe is lateral and becomes filiform toward the proximal and distal ends. Proximal raphe ends are slightly expanded and tipped slightly toward the ventral side. Distal raphe fissures are deflected dorsally. Striae are slightly radiate throughout and sometimes curved, especially about the central area. Short striae about the central area are more widely spaced and striae near the valve ends are more closely spaced. Areolae in the striae are not visible in LM.
Basionym: Cymbella hybrida
Author: Grunow 1878
Length Range: 45 µm
Width Range: 9.0 µm
Striae in 10 µm: 11
Cleve, P.T. (1894). Synopsis of the Naviculoid Diatoms, Part I. Kongliga Svenska-Vetenskaps Akademiens Handlingar 26(2):1-194, 5 pls.
Cleve, P.T. and Möller, J.D. (1878). Collection of 324 diatom slides with accompanying analyses of A. Grunow. Parts 1-6 (1877-1882), Upsala.
Krammer, K. (2003). Cymbopleura, Delicata, Navicymbula, Gomphocymbellopsis, Afrocymbella. Diatoms of Europe. Diatoms of the European Inland Waters and Comparable Habitats 4: 1-530.
Krammer, K. and Lange-Bertalot, H. (1986). Bacillariophyceae. 1. Teil: Naviculaceae. In: Ettl, H., J. Gerloff, H. Heynig and D. Mollenhauer (eds.) Süsswasserflora von Mitteleuropa, Band 2/1. Gustav Fisher Verlag, Jena. 876 pp.
Patrick, R.M. and Reimer, C.W. (1975). The Diatoms of the United States, exclusive of Alaska and Hawaii, V. 2. Monographs of the Academy of Natural Sciences of Philadelphia 13.
Patrick & Reimer (1975) report this species from Connecticut, South Carolina, Michigan, and Montana. Krammer (2003) reports Cymbopleura hybrida from arctic, sub-arctic, and alpine regions where it prefers oligotrophic waters with low to moderate electrolyte content. The specimens shown here were collected from a tundra lake above the Arctic Circle in Nunavut, Canada (photo below).
Bloody Falls Tundra Lake, Nunavut, Canada: home of Cymbopleura hybrida.
Credit/Source: Beverly Boynton, Adventurers and Scientists for Conservation