(Krammer) Krammer 2003 Category: Asymmetrical biraphid
BASIONYM: Cymbella subcuspidata Krammer 1982
Contributor: Loren Bahls - August 2012
Length Range: 67-111 µm
Width Range: 19-25 µm
Striae in 10 µm: 9-12 (dorsal and ventral) at the valve center; 12-15 (dorsal) and 13-16 (ventral) at the apices
Valves are elliptic-lanceolate and slightly dorsiventral with almost equally arched dorsal and ventral margins that taper towards bluntly rounded rostrate to subcapitate apices. The length to width ratio is 3.3-4.4. The moderately narrow axial area widens gradually from the apices towards a large rounded and asymmetric central area. The raphe is lateral and narrows towards the distal and proximal ends. Proximal raphe ends are deflected ventrally and shaped like a crochet hook or a crosier. Terminal raphe fissures are deflected dorsally. Striae are radiate throughout and more closely spaced towards the apices. Areolae are easily resolved in LM and number 19-22 in 10 µm.
Basionym: Cymbella subcuspidata
Author: Krammer 1982
Length Range: µm
Striae in 10 µm:
Krammer, K. (1982). Valve morphology and taxonomy in the genus Cymbella C.A. Agardh. Morphology of Diatom Valves 11: 1-299.
Krammer, K. (2003). Cymbopleura, Delicata, Navicymbula, Gomphocymbellopsis, Afrocymbella. Diatoms of Europe. Diatoms of the European Inland Waters and Comparable Habitats 4: 1-530.
Cymbopleura subcuspidata occurs frequently in lakes and ponds in the northern Rocky Mountains. Concurrent measurements of pH in waters where C. subcuspidata has been collected range from 6.73 to 7.78. Specific conductance in these waters ranges from 22 to 53 µS/cm.
Upper Two Medicine Lake, Glacier National Park, Montana: home of Cymbopleura subcuspidata.
Credit/Source: Loren Bahls
Rubideau Marsh, Glacier National Park, Montana: home of Cymbopleura subcuspidata.
Credit/Source: E. William Schweiger, National Park Service