(Sovereign) Bahls 2013 Category: Asymmetrical biraphid
BASIONYM: Cymbella rainierensis Sovereign 1963
REPORTED AS: Cymbella rainierensis (Patrick and Reimer 1975, pg 31, pl. 4, fig. 8) | Cymbopleura subaustriaca (Zimmermann et al. 2010, pg 50, pl. 63, figs 8-11) | Cymbopleura americana ((Schmidt) Krammer 2003, pl. 59, figs 1-3)
Contributor: Loren Bahls - September 2012
Length Range: 44-82 µm
Width Range: 13.2-16.4 µm
Striae in 10 µm: 8-11 at the valve center, 13-15 near the apices
Valves are lanceolate and slightly dorsiventral with weakly protracted rostrate or apiculate apices. The axial area is narrow and positioned near the central apical axis. The central area is approximately half the width of the valve and rounded rhomboid in shape. The raphe is straight and lateral, becoming filiform at the proximal and distal ends. Proximal raphe ends are displaced ventrally, with slightly expanded ends that are indistinctly hooked toward the ventral side. Distal raphe ends are comma shaped and dorsally deflected. Striae are radiate throughout and indistinctly punctate. In most populations, areola density is 28-34 in 10 µm, although one population had an areola density of 20- 24 in 10 µm.
This taxon may be conspecific with Cymbella americana Schmidt. Apparently, there is no type material for C. americana. The illustrations from Schmidt’s Atlas are reproduced in Krammer (2003, figs 59:1, 2). Krammer also presented an image of a taxon identified as C. americana from Tierra del Fuego (Krammer 2003, fig. 59:3).
Basionym: Cymbella rainierensis
Author: Sovereign 1963
Length Range: 42-79 µm
Width Range: 13-16 µm
Striae in 10 µm: 9-11 in the middle, closer at the ends
Valves naviculoid, almost symmetrical in outline, lanceolate with rounded ends, 42-79 µm long by 13-16 µm wide. Raphe straight, almost on the median line. Axial area narrow lanceolate, central area rhomboidal. Striae lightly radial, at the middle 9 to 11 in 10 µm, closer at the ends, finely lineolate.
Bahls, L. (2013). New diatoms (Bacillariophyta) from western North America. Phytotaxa 82(1): 7-28.
Foged, N. (1981). Diatoms in Alaska. Bibliotheca Phycologica, Band 53, J. Cramer, Vaduz, 317 pp.
Krammer, K. (2003). Cymbopleura, Delicata, Navicymbula, Gomphocymbellopsis, Afrocymbella. Diatoms of Europe. Diatoms of the European Inland Waters and Comparable Habitats 4: 1-530.
Patrick, R.M. and Reimer, C.W. (1975). The Diatoms of the United States, exclusive of Alaska and Hawaii, V. 2. Monographs of the Academy of Natural Sciences of Philadelphia 13.
Schmidt, A. (-). (1874-1959). Atlas der Diatomaceen-Kunde, von Adolf Schmidt, continued by Martin Schmidt, Friedrich Fricke, Heinrich Heiden, Otto Muller, Friedrich Hustedt. Reprint 1984, Koeltz Scientific Books, Konigstein, 480 plates.
Sovereign, H.E. (1963). New and rare diatoms from Oregon and Washington. Proceedings of the California Academy of Sciences, series 4, 31(14): 349-368.
Zimmermann, C., Poulin, M. and Pienitz, R. (2010). Diatoms of North America: The Pliocene-Pleistocene freshwater flora of Bylot Island, Nunavut, Canadian High Arctic. Iconographia Diatomologica (H. Lange-Bertalot, ed.), Volume 21, A.R.G. Gantner Verlag K.G., Ruggell, 407 pp.
This taxon has been recorded from several lakes, ponds and fens in Glacier National Park, Montana. In these waters it prefers circumneutral pH with low specific conductance. The type locality is Mowich Lake in Mount Rainier National Park, where pH measured 5.8 to 7.2. Sovereign (1963) reports that it is also found in over a dozen high mountain lakes in the Mount Rainier area. In the Montana Diatom Collection, we have two records from Mount Rainier National Park: Dewey Lake and a small pond near Dewey Lake. Zimmermann et al. (2010) reported this species (as Cymbopleura subaustriaca) from the Canadian High Arctic. Foged (1981) reported it from Alaska.
Frog pond near Dewey Lake, Mount Rainier National Park, Washington.
Credit/Source: Ryan Davis, Adventurers and Scientists for Conservation
Cymbella rainierensis was transferred to Cymbopleura rainierensis by Bahls (2013). The page now reflects that transfer. - S. Spaulding