Stauroneis pseudagrestis
Lange-Bert. and Werum 2004 Category: Symmetrical biraphid
LM scalebar = 10 µm = 80 pixels.
Observations
Contributor: Loren Bahls - May 2012
Length Range: 27-43 µm
Width Range: 6.4-9.4 µm
Striae in 10 µm: 23-26
Description
Valves are lanceolate with capitate apices. The axial area is narrow and widens very little or not at all near the central area. The stauros is a very broad, with curved striae on the margins. The raphe is filiform with unexpanded proximal ends that are bent slightly in the same direction. Striae are strongly radiate. Areolae are difficult to resolve in LM and number about 30 in 10 µm.
Original Description
Basionym:
Author: Lange-Bert. and Werum 2004
Length Range: 26-35 µm
Width Range: 6.5-7.0 µm
Striae in 10 µm: 24-27
Original Description
Original Images
Cite This Page:
Bahls, L. (2012). Stauroneis pseudagrestis. In Diatoms of the United States. Retrieved April 22, 2018, from http://westerndiatoms.colorado.edu/taxa/species/stauroneis_pseudagrestis
Species: Stauroneis pseudagrestis
Contributor: Loren Bahls
Reviewer: Rex Lowe
Image Credit: Loren Bahls
- Valves lanceolate
- Apices capitate
- Stauros relatively large
- Striae strongly radiate
- Proximal raphe ends bent
Stauroneis pseudagrestis has lanceolate valves with capitate apices and a large stauros with curved margins. The striae are strongly radiate and proximal raphe ends are bent slightly to the same side.
Compare
Stauroneis agrestis is smaller with a higher stria density and straight proximal raphe ends. Stauroneis kriegeri is smaller and has subcapitate apices, a nearly rectangular stauros and straight proximal raphe ends. Stauroneis reichardtii is larger with a narrower stauros and straight proximal raphe ends.
Stauroneis agrestis
Stauroneis kriegeri
Stauroneis reichardtii
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.
Werum, M. and Lange-Bertalot, H. (2004). Diatoms in springs, from Central Europe and elsewhere under the influence of hydrogeology and anthropogenic impages. Iconographia Diatomologica 13: 1-417.
Links & ID's
Index Nominum Algarum (INA)
California Academy of Sciences (CAS)
North American Diatom Ecological Database (NADED)
NADED ID:
Autecology Discussion
Stauroneis pseudagrestis is uncommon in the U. S. and reported to date only from three small lakes and ponds in southwestern Montana. Here it prefers slightly alkaline water (pH 7.34-7.83) with low specific conductance (31-41 µS/cm). This species was described from springs in Germany.
Images
Bloody Dick Pond No. 6, Beaverhead County, Montana: home of Stauroneis pseudagrestis.
Credit/Source: Loren Bahls