Contributor: Loren Bahls - June 2016
Length Range: 23-36 µm
Width Range: 7.2-9.2 µm
Striae in 10 µm: 10-12 dorsal, 11-13 ventral near valve center
Valves are strongly dorsiventral with narrow rostrate to subrostrate apices. The dorsal margin is strongly arched and the ventral margin is weakly convex. The axial area is narrow and linear. The central area is very small. Two, rarely 1 or 3, stigmata are present at the proximal ends of the middle ventral striae. The raphe is lateral, becoming filiform near the indistinct terminal fissures. Proximal raphe ends are reverse-lateral and deflected to the ventral side. Striae are slightly radiate, becoming strongly radiate near the apices. Areolae number 26-30 in 10 µm.
Author: Krammer 2002
Length Range: 23-34 µm
Width Range: 7.4-8.7 µm
Striae in 10 µm: 10-12 at the valve center, 14-15 near the ends
Krammer, K. (2002). The genus Cymbella. Diatoms of Europe. Diatoms of the European Inland Waters and Comparable Habitats 3: 1-584.
Cymbella affiniformis has been recorded from two small spring creeks in the Flathead and Mission Valleys of western Montana. At the time it was described, this species was known only from the type locality, a pond in southern Germany (Krammer 2002).
Stinger Creek, Lake County, Montana: Home of Cymbella affiniformis.
Credit/Source: Montana Department of Fish, Wildlife and Parks