Krammer 2003 Category: Asymmetrical biraphid
BASIONYM: Cymbopleura perprocera Krammer 2003
Contributor: Loren Bahls - January 2014
Length Range: 62.3-114.4 µm
Width Range: 19.6-25.1 µm
Striae in 10 µm: 8-9 at the valve center, 12-13 near the apices on the dorsal side
Valves are weakly dorsiventral and lanceolate with narrow beaked apices. The dorsal margin is more strongly arched than ventral margin, which may be nearly flat in the smallest specimens. The axial area is moderately wide, about one-fourth to one-third the width of the valve. The central area is rounded and slightly wider than the axial area. The raphe is lateral and narrows near the weakly expanded proximal ends, which are tipped slightly towards the ventral side. Distal raphe ends are bayonet-shaped and more or less straight. Striae are radiate, but become parallel very near the apices. Areolae in the striae are easily resolved in LM and number 16-22 in 10 µm.
Basionym: Cymbopleura perprocera
Author: Krammer 2003
Length Range: 84-124 µm
Width Range: 23-26 µm
Striae in 10 µm: 8-9 at the valve center, 15-16 near 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 perprocera was described from material collected from a Sphagnum moor pond in northwest Finland. Krammer (2003) reports this species has a sporadic distribution in lakes of Finnish Lapland, where the water is low in nutrients and electrolytes. The specimens illustrated here were collected from Hoskins Lake, a lowland lake surrounded by conifer forest in northwest Montana (photo below). Here pH measured 7.6 and specific conductance measured 67 µS/cm on the day that C. perprocera was collected.
Hoskins Lake, Lincoln County, Montana: home of Cymbopleura perprocera.