Krammer 2003 Category: Asymmetrical biraphid
BASIONYM: Cymbopleura incertiformis Krammer 2003
Contributor: Loren Bahls - January 2014
Length Range: 29.5-60.7 µm
Width Range: 7.0-9.4 µm
Striae in 10 µm: 14-17 at the valve center, 20-24 at the ends on the dorsal side
Valves are lanceolate and not, or just barely, dorsiventral. Apices are either not protracted, or they are weakly protracted and subrostrate. The narrow axial area widens somewhat near the valve center. The central area is rounded and more or less symmetric, formed by shallow depressions on the dorsal and ventral sides. The raphe is lateral, becoming filiform toward the ends. Proximal raphe ends are deflected ventrally and terminate with weakly expanded pores. Distal raphe ends are hooked toward the dorsal side. Striae are radiate throughout and more widely spaced near the valve center. Areolae are difficult to resolve in LM and number 28-32 in 10 µm.
Basionym: Cymbopleura incertiformis
Author: Krammer 2003
Length Range: 24-60 µm
Width Range: 6.5-8.5 µm
Striae in 10 µm: 15-19 at the valve center, up to 20 towards the apices on the dorsal side
Krammer, K. (2003). Cymbopleura, Delicata, Navicymbula, Gomphocymbellopsis, Afrocymbella. Diatoms of Europe. Diatoms of the European Inland Waters and Comparable Habitats 4: 1-530.
Cymbopleura incertiformis is widespread and locally abundant in lakes and ponds of the northern Rocky Mountains and North Cascades. In lakes with water quality data, pH ranged from 6.7 to 7.8 and specific conductance ranged from 10 to 53 µS/cm. Krammer (2003) reports variety incertiformis as “widely distributed in the subarctic, nordic, and alpine area in oligotrophic to dystrophic habitats with commonly low electrolyte content, sometimes in large numbers”.
Goat Flats Tarn, Snohomish County, Washington: home of Cymbopleura incertiformis.
Credit/Source: Craig Weiland, Adventurers and Scientists for Conservation.