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Stauroneis pikuni

L.L.Bahls 2010      Category: Symmetrical biraphid

REPORTED AS: Stauroneis gracilior "Zackenberg" (Van de Vijver et al. 2004) 

Stauroneis phoenicenteron


Stauroneis pseudagrestis

LM scalebar = 10 µm = 40 pixels.


Contributor: Loren Bahls - December 2011
Length Range: 53-64 µm
Width Range: 9.0-12.0 µm
Striae in 10 µm: 24-28


Valves are lanceolate to rhombic-lanceolate with gradually narrowed capitate apices. Raphe branches are moderately lateral, becoming filiform at the distal and proximal ends. Proximal raphe ends are straight and not expanded. The axial area is narrow and linear, barely wider than the raphe, and expands slightly at the central area. The central area is a rectangular stauros. Striae are radiate throughout. Areolae are round to transapically oblong, irregularly spaced, and number 20-24 in 10 µm.

Original Description

Author: L.L.Bahls 2010
Length Range: 53-64 µm
Width Range: 9-12 µm
Striae in 10 µm: 24-28

Original Description

Valves lanceolate with gradually narrowed capitate to subcapitate ends. Length 53-64 µm, width 9-12 µm. Raphe fissures moderately lateral, becoming filiform at the distal and proximal ends. Proximal raphe endings straight, pores not inflated or deflected. Axial area narrow and linear, barely wider than the raphe, flaring slightly at the central area. Central area a narrow rectangular fascia. Striae radiate throughout, 24-28 in 10 µm. Striae puncta fine, round to oblong, and irregularly spaced, 20-24 in 10 µm. For measurements, n = 22 valves.

Original Images

Cite This Page:
Bahls, L. (2011). Stauroneis pikuni. In Diatoms of the United States. Retrieved May 25, 2018, from

Species: Stauroneis pikuni

Contributor: Loren Bahls

Reviewer: Mark Edlund


Bahls, L. (2010). Stauroneis in the Northern Rockies: 50 species of Stauroneis sensu stricto from western Montana, northern Idaho, northeastern Washington and southwestern Alberta, including 16 species described as new. Northwest Diatoms, Volume 4. The Montana Diatom Collection, Helena, 172 pp.

Reichardt, E. (1995). Die Diatomeen (Bacillariophyceae) in Ehrenbergs Material von Cayenne, Guyana Gallica (1843). Volume 1, Iconographia Diatomologica (H. Lange-Bertalot, ed.). Koeltz Scientific Books, Konigstein.

Van de Vijver, B., Beyens, L. and Lange-Bertalot, H. (2004). The genus Stauroneis in Arctic and Antarctic Regions. Bibliotheca Diatomologica 50, 312 pp.

Links & ID's

Index Nominum Algarum (INA)

Original INA

California Academy of Sciences (CAS)

Stauroneis pikuni CAS

North American Diatom Ecological Database (NADED)


Autecology Discussion

Stauroneis pikuni is widely distributed in lakes and ponds throughout the Northern Rockies, but is rarely found in abundance. In waters where Stauroneis pikuni occurs, pH ranges from 6.6 to 7.3 and specific conductance ranges from 8 to 71 µS/cm. Van de Vijver et al. (2004) reported this taxon (as Stauroneis gracilior “Zackenberg”) from the Zackenberg area of East Greenland.


Loren Bahls at Two Medicine Campground Pond, Glacier National Park, Montana: type locality for Stauroneis pikuni.

Credit/Source: Marina Potapova