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A Diatom - Stauroneis subhyperborea
Other Names:
Stauroneis sacajaweae
State Rank Reason (see State Rank above)
Stauroneis subhyperborea is considered to be a rare to uncommon cold-water stenotherm that is threatened by climate change and regional warming (Bahls 2018).
General Description
Morphological Category – Symmetric biraphid
Valves lanceolate with subrostrate apices. A pseudoseptum occupies both apices. Axial Area wide, about three times the width of the raphe. Central Area has a stauros shaped like a bow tie. Raphe lateral, becoming thread-like near the proximal and distal ends. Proximal raphe ends bent weakly to one side and tipped with inflated pores. Distal raphe ends curved to one side. Striae radiate throughout. Areolae distinct, 16-18 in 10 µm.
Length: 56-86 µm
Width: 12-16 µm
Striae in 10 µm: 22-26.
Diagnostic Characteristics
Distinguished from
Stauroneis superhyperborea by its smaller valves and narrower apices.
Distinguished from
Stauroneis hyperborea by its wider apices and higher striae and areolae density. Distinguished from
Stauroneis clarkii by its narrower apices and wider axial area.
Range Comments
Type Locality
Zackenberg area, East Greenland
Global Distribution
Recorded from a seep along the Going-to-the-sun Road and from Red Rock Lake in Glacier National Park; also from a flowing spring at the base of Square Butte near Geraldine, Montana. Previously, this species was known only from the type locality in Greenland.
Number of Observations in Montana Diatom Collection Database (Bahls 1968-2019): 3
Montana: 3
Habitat
Seeps and springs in the mountains (Bahls 2021).
Ecology
Cold, circumneutral waters with low nutrients and 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
As a rare, cold-water stenothermal diatom in Montana and the contiguous United States, Bahls (2018) rated Stauroneis subhyperborea at moderate risk of extirpation due to 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, L. 2018. Potential loss of cold-water stenothermal diatoms (Bacillariophyta) from their southern refugia in the western United States. Diatom Research 32: 483-494.
- 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, L. 2012. Five new species of Stauroneis (Bacillariophyta, Stauroneidaceae) from the northern Rocky Mountains, USA. Phytotaxa 67: 1-8.
- 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.
- 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"
