Krammer 2002 Category: Asymmetrical biraphid
BASIONYM: Cymbella stuxbergi var. intermedia Wislouch 1924
REPORTED AS: Cymbella stuxbergii var. siberica (Foged 1981, p. 75, plate L, fig. 1)
Contributor: Loren Bahls - October 2012
Length Range: 84-121 µm
Width Range: 20-26 µm
Striae in 10 µm: 7-11
Valves are moderately dorsiventral with arched dorsal margins and weakly concave ventral margins with a slightly tumid center. Axial area is about 3-4 times wider than the raphe and follows the median line of the valve. Central area is large and elliptic in shape. From 6 to 9 isolated stigmata form a straight or slightly curved line along the apical axis on the ventral side of the central nodule and some distance from the middle striae. The raphe is lateral and becomes filiform near the proximal and distal ends. Proximal raphe ends are straight with expanded tips. Distal raphe ends are hooked at nearly right angles toward the dorsal margin. Striae are radiate throughout. Areolae are easily resolved in LM and number 14-18 in 10 µm.
Basionym: Cymbella stuxbergi var. intermedia
Author: Wislouch 1924
Length Range: µm
Striae in 10 µm:
Foged, N. (1981). Diatoms in Alaska. Bibliotheca Phycologica, Band 53, J. Cramer, Vaduz, 317 pp.
Krammer, K. (2002). The genus Cymbella. Diatoms of Europe. Diatoms of the European Inland Waters and Comparable Habitats 3: 1-584.
Wislouch, S.M. (1924). Beiträge zur Diatomeenflora von Asien. II. Neue Untersuchungen über die Diatomeen des Baikalsees. Berichte der Deutschen Botanishen Gesellschaft 42: 163-173.
Cymbella amplificata was recently collected from two lakes in King County, Washington by Lisa White, a volunteer with Adventurers and Scientists for Conservation. These are the first confirmed records for this species in the lower 48 states. The type locality is Lake Baikal and it has also been reported from other sites in Siberia. Foged (1981) reported it from Alaska (as Cymbella stuxbergii var. siberica). According to Krammer (2002) this diatom prefers oligotrophic waters with a low to average electrolyte content.
Glacier Lake, King County, Washington—one of only two lakes in the lower 48 states that is known to support a population of Cymbella amplificata.
Credit/Source: Lisa White, Adventurers and Scientists for Conservation