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A Diatom - Stauroneis americana
Other Names:
Pleurostaurum americana
General Description
Morphological Category – Symmetric biraphid
Valves broadly lanceolate with bluntly rounded apices. A prominent pseudoseptum is present at each apex.
Axial Area broad and linear, about three times the width of the raphe.
Central Area a rectangular stauros, a bit wider than the axial area, widening very slightly near the valve margins.
Raphe lateral, becoming filiform near the central area. Proximal raphe ends nearly straight, weakly expanded.
Striae slightly radiate throughout.
Areolae coarse, 9-14 in 10 µm.
Size RangeLength 136-214 µm.
Width 32-46 µm.
Striae in 10 µm 11-14.
Useful Link:
Diatom Glossary [Diatoms of North America website]
Diagnostic Characteristics
Stauroneis americana differs from
S. finlandia,
S. javanica,
S. kishinena and
S.ursamaioris by its straight, weakly expanded proximal raphe ends.
Stauroneis americana also lacks the distinctly protracted valve apices of
S. finlandia and
S. ursamaioris.
Range Comments
Widely distributed in the Rocky Mountains, but rarely found in abundance.
Type Locality
North America (fossil)
Number of Observations in Montana Diatom Collection Database (Bahls 1968-2019): 8;
Montana: 6
Habitat
Lakes, ponds and wetlands in the mountains.
Ecology
Cool, alkaline waters with low nutrients and low to moderate conductivity (Bahls 2021).
Reproductive Characteristics
Diatoms typically reproduce by cell division (mitosis) and occasionally by meiosis—sexual reproduction in which female and male gametes combine to form a specialized zygote called an auxospore. Repeated divisions result in cells of a population becoming progressively smaller and smaller. When cells reach a critically small size, sexual reproduction is initiated, resulting in an auxospore and initial cells that are the largest attainable for the species, after which cell division and size reduction resume (Amato 2010).
Stewardship Responsibility
Threats or Limiting Factors
Climate change and regional warming.
References
- Literature Cited AboveLegend:
View Online Publication
Amato, A. 2010. Diatom reproductive biology: living in a crystal cage. The International Journal of Plant Reproductive Biology 2(1): 1-10.- Bahls, Loren. 1968-Present. Montana Diatom Collection Database. Missoula, Montana.
- Bahls, Loren. 2021. Diatoms of Montana and Western North America: Catalog and Atlas of Species in the Montana Diatom Collection Volume 1. The Academy of Natural Sciences of Philadelphia Special Publication 24. 508pp.
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?- Bahls, Loren. 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.
- Schmidt, A. 1874-1959. Atlas der Diatomaceen-Kunde, von Adolf Schmidt, continued by Martin Schmidt, Friedrich Fricke, Heinrich Heiden, Otto Muller, Friedrich Hustedt. Reprint 1984, Koeltz Scientific Books, Konigstein, 480 plates.
- Van de Vijver, B., Beyens, L. and Lange-Bertalot, H. 2004. The genus Stauroneis in Arctic and Antarctic Regions. Bibliotheca Diatomologica 50, 312 pp.
- Web Search Engines for Articles on "A Diatom"
