(Ehrenberg) Cleve 1891 Category: Symmetrical biraphid
BASIONYM: Cocconeis finnica Ehrenberg 1838
Contributor: Loren Bahls - December 2011
Length Range: 52-107 µm
Width Range: 33-53 µm
Striae in 10 µm: 7-9
Valves are broadly elliptical. The longitudinal canals are a distinctive lanceolate shape about 1/3 to 1/2 the width of the valve at center, which narrows towards the valve apices. The axial area is occupied almost completely by a broad raphe sternum that encloses the raphe. The central area is small and elliptical. Striae consist of double rows of areolae, one row may appear more prominent than the adjacent row. Striae are radiate throughout and extend onto the longitudinal canals. Areolae are distinct in LM and number 12-14 in 10 µm, but are more closely spaced over the longitudinal canals.
Basionym: Cocconeis finnica
Author: Ehrenberg 1838
Length Range: µm
Striae in 10 µm:
Cleve, P.T. (1891). The Diatoms of Finland. Actas Societas Pro Fauna et Flora Fennica 8 (2): 1-68.
Ehrenberg, C.G. (1838). Die Infusionsthierchen als vollkommene Organismen. Ein Blick in das tiefere organische Leben de Natur. erlag von Leopold Voss, Leipzig. pp. 1-xvii, 1-548, pls. 1-64.
Krammer, K. and Lange-Bertalot, H. (1986). Bacillariophyceae. 1. Teil: Naviculaceae. In: Ettl, H., J. Gerloff, H. Heynig and D. Mollenhauer (eds.) Süsswasserflora von Mitteleuropa, Band 2/1. Gustav Fisher Verlag, Jena. 876 pp.
Patrick, R.M. and Reimer, C.W. (1966). The Diatoms of the United States exclusive of Alaska and Hawaii, V. 1. Monographs of the Academy of Natural Sciences of Philadelphia 13.
Diploneis finnica is a northern species. There are seven records of this species in the Montana Diatom Collection from lakes and streams in western Montana and northern Idaho. The pH of these waters ranges from 7.4 to 8.2 and specific conductance ranges from 39 to 90 µS/cm. Patrick and Reimer (1966) report Diploneis finnica from New England and the Pacific Northwest in “fresh water, particularly standing water, indifferent to small amounts of salt”. As the specific epithet suggests, the type locality of this species is in Finland.
Ross Creek, Lincoln County, northwest Montana: home of Diploneis finnica.