Krammer 1997 Category: Asymmetrical biraphid
BASIONYM: Encyonopsis neoamphioxys Krammer 1997
SYNONYM(S): Navicula amphioxys Kützing 1844, p. 91, fig. 28:37 | Cymbella amphioxys (Kützing) Cleve 1894, p. 164 | Cymbella navicula var. amphioxys Grunow in Cleve and Möller 1879
REPORTED AS: Cymbella amphioxys (Krammer and Lange-Bertalot 1986, p. 328, fig. 135:11-13)
Contributor: Loren Bahls - January 2014
Length Range: 41-59 µm
Width Range: 4.9-7.6 µm
Striae in 10 µm: 13-15 at the valve center, 15-18 at the ends on the dorsal side
Valves are linear-lanceolate and distinctly dorsiventral. The dorsal margin is more strongly arched than the ventral margin, which is sometimes almost flat and sometimes slightly tumid in the middle. The apices are subrostrate, only weakly protracted, and tipped ventrally. The axial area is narrow. The central area is small and rounded. A single stigma lies at the end of a short median stria on the dorsal side of the central area. The raphe is lateral. Proximal raphe ends are weakly expanded and tipped towards the dorsal side. Distal raphe ends are hooked towards the ventral side. Striae are radiate near the valve center and then become parallel and finally convergent at the apices. Areolae in the striae are very fine and difficult to resolve in LM.
Basionym: Encyonopsis neoamphioxys
Author: Krammer 1997
Length Range: 45-72 µm
Width Range: 6-8 µm
Striae in 10 µm: 14-18
Cleve, P.T. (1894). Synopsis of the Naviculoid Diatoms, Part I. Kongliga Svenska-Vetenskaps Akademiens Handlingar 26(2):1-194, 5 pls.
Cleve, P.T. and Möller, J.D. (1878). Collection of 324 diatom slides with accompanying analyses of A. Grunow. Parts 1-6 (1877-1882), Upsala.
Ehrenberg, C.G. (1843). Verbreitung und Einfluß des mikroskopischen Lebens in Süd- und Nord-Amerika. Abhandlungen der Königlichen Akademie der Wissenschaften zu Berlin, 1841: 291-445, 4 Tafel.
Krammer, K. (1997). Die cymbelloiden Diatomeen. Eine Monographie der weltweit bekannten Taxa. Teil 2. Encyonema part., Encyonopsis and Cymbellopsis. Bibliotheca Diatomologica 37:1-469.
Kützing, F.T. (1844). Die kieselschaligen Bacillarien oder Diatomeen. Nordhausen. 152 pp., 30 pls.
This taxon is uncommon but widely distributed in small lakes, ponds and fens in the northern Rocky Mountains and North Cascades. In one of these lakes, Johns Lake in Glacier National Park, Montana, pH measured 7.2 and specific conductance measured 30 µS/cm at the time of collection. In Drosera Fen on the Indian Meadows Research Natural Area in western Montana, pH measured 6.8 and specific conductance measured 19 µS/cm. Krammer (1997) reports that E. neoamphioxys has a nordic-alpine distribution and prefers oligotrophic waters.
Small tarn southwest of Bigelow Mountain, North Cascades, Chelan County, Washington: home of K. neoamphioxys.
Credit/Source: Craig Weiland, Adventurers and Scientists for Conservation.
This taxon page appeared under the genus Encyonopsis. The page was updated to follow the transfer to Kurtkrammeria made by Bahls (2015). - S. Spaulding