(Grunow) Krammer 2003 Category: Asymmetrical biraphid
BASIONYM: Cymbella pisciculus var. incerta Grunow 1878
SYNONYM(S): Cymbella incerta (Grunow) Cleve 1894
REPORTED AS: Cymbella incerta (Krammer and Lange-Bertalot 1986, p. 329, figs 136: 1-12)
Contributor: Loren Bahls - April 2013
Length Range: 31-58 µm
Width Range: 7.3-10.2 µm
Striae in 10 µm: 15-16 at the valve center, 18-20 near the apices
Valves are lanceolate and moderately dorsiventral with rounded apices. Except for the largest valves, where dorsal and ventral margins are equally arched, the dorsal margin is much more strongly arched than the ventral margin. In small specimens, the ventral margin may be flat, or even slightly concave. The axial area is narrow, widening gradually toward the ellliptic central area, which is from 1/3 to 1/2 the width of the valve. The axial and central areas form a narrow longitudinal lanceolate space that is displaced somewhat to the ventral side of the apical axis. The raphe is lateral, becoming reverse-lateral near the central valve. The proximal ends are slightly inflated and deflected toward the ventral side. The distal raphe fissures are narrow and hooked toward the dorsal side. Striae are slightly radiate, becoming more strongly radiate near the apices. Areolae in the striae number 28-32 in 10 µm.
Basionym: Cymbella pisciculus var. incerta
Author: Grunow 1878
Length Range: µm
Striae in 10 µm:
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.) Susswasserflora von Mitteleuropa, Band 2/1. Gustav Fisher Verlag, Jena. 876 pp.
Cymbopleura incerta has been collected from Johnson Lake in southwestern Montana (photo below). Johnson Lake is at an elevation of 2329 m in the Anaconda Mountain Range. Here, on the collection date, pH measured 8.2 and specific conductance measured 140 µS/cm. In Europe, Krammer (2003) reports this species from oligotrophic habitats with low to moderate conductivity in northern and alpine regions.
Johnson Lake, Anaconda-Pintler Wilderness, Deerlodge National Forest, southwestern Montana: home of Cymbopleura incerta.
Credit/Source: George Wuerthner