Stauroneis gracilis
Ehrenberg 1843 Category: Symmetrical biraphid
BASIONYM: Stauroneis gracilis Ehrenberg 1843
LM scalebar = 10 µm = 40 pixels.
Observations
Contributor: Loren Bahls - December 2011
Length Range: 68-127 µm
Width Range: 13-22 µm
Striae in 10 µm: 15-18
Description
Valves are elliptic-lanceolate with subrostrate, broadly rounded apices. The axial area is linear to narrowly lanceolate and two to three times wider than the raphe. The stauros is rectangular, often widening slightly towards the valve margins. Short striae are absent from the central area. The raphe is lateral with curved and inflated proximal ends. Terminal raphe fissures are shaped like question marks and hooked toward the secondary side. Striae are radiate throughout. Areolae number 18-22 in 10 µm.
Original Description
Basionym: Stauroneis gracilis
Author: Ehrenberg 1843
Length Range: µm
Striae in 10 µm:
Original Description
Original Images
Cite This Page:
Bahls, L. (2011). Stauroneis gracilis. In Diatoms of the United States. Retrieved May 19, 2013, from http://westerndiatoms.colorado.edu/taxa/species/stauroneis_gracilis
Species: Stauroneis gracilis
Contributor: Loren Bahls
Reviewer: Mark Edlund
Image Credit: Loren Bahls
- Valves elliptic-lanceolate
- Apices subrostrate, broadly rounded
- Proximal raphe ends curved, expanded
- Areolae 18-22 in 10 µm
Stauroneis gracilis has elliptic-lanceolate valves that are 68 to 127 µm long. The apices are subrostrate and broadly rounded. Proximal raphe ends are curved and expanded. Areolae number 18-22 in 10 µm.
Compare
Stauroneis supergracilis has narrower valves relative to their length, more subtly protracted apices, and a lower areolae density (14-18 in 10 µm). Valves of S. subborealis are more linear, especially in small specimens. Stauroneis phoenicenteron lacks protracted apices and has straight proximal raphe ends.
Stauroneis phoenicenteron
Stauroneis subborealis
Stauroneis supergracilis
Citations
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.
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.
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)
California Academy of Sciences (CAS)
North American Diatom Ecological Database (NADED)
NADED ID:
Autecology Discussion
Stauroneis gracilis is widely distributed in lakes, ponds, and wetlands in the Northern Rockies. The pH of these waters ranges from 5.5 to 7.4 (mean pH = 6.7) and specific conductance ranges from 7 to 192 µS/cm (mean SC = 36 µS/cm). Van de Vijver et al. (2004) report this species as widely distributed in both the Arctic and Antarctic, where it is present in a large variety of habitats ranging from small, very shallow pools to large, deep lakes. In these waters the pH ranges from 6.0 to 8.3 and specific conductance ranges from 50 to 350 µS/cm.
Images
Red Eagle Pond, Glacier National Park, Montana: home of Stauroneis gracilis.
Credit/Source: E. William Schweiger, National Park Service