(Grunow) Krammer 2003 Category: Asymmetrical biraphid
BASIONYM: Cymbella hybrida Grunow ex Cleve 1894
REPORTED AS: Cymbella hybrida (Patrick and Reimer 1975, p. 32, plate 4, fig. 10) | Cymbella hybrida (Krammer and Lange-Bertalot 1986, p. 337, plate 145, figs 1-3 (not figs 4, 5)
Contributor: Loren Bahls - August 2012
Length Range: 38-49 µm
Width Range: 10.8-11.9 µm
Striae in 10 µm: 10-13 at the valve center, 15-16 near the apices
Valves are linear-elliptic and slightly dorsiventral, with barely convex dorsal and ventral margins and abruptly constricted rostrate to capitate apices. The axial area is relatively narrow, 2-3 times wider than the raphe. The central area is large and transversely oval or rectangular. The raphe is lateral, becoming filiform near the proximal ends. Proximal raphe ends have small hooks deflected towards the ventral margin. Distal raphe fissures are deflected dorsally. Striae are parallel at the valve center and radiate towards the apices. Areolae are difficult to resolve in LM and number 28-34 in 10 µm.
Basionym: Cymbella hybrida
Author: Grunow ex Cleve 1894
Length Range: µm
Striae in 10 µm:
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.) Susswasserflora 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.
Cymbopleura hybrida is uncommon in lakes and ponds of the northern Rocky Mountains, where it prefers cold, oligotrophic, circumneutral waters (pH range: 6.80-7.77) with low to moderate levels of dissolved solids (specific conductance range: 53-250 µS/cm). 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.
Lake McDonald, Glacier National Park, Montana: home of Cymbopleura hybrida.
Credit/Source: National Park Service webcam