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A Diatom - Gomphadelpha montana
Other Names:
Gomphoneis montana
General Description
Morphological Category – Asymmetric biraphid
Valves lanceolate with acutely pointed headpoles. Footpole capitate and separated from the valve body by a very narrow isthmus.
Axial Area very narrow, barely wider than the raphe, and merges with a small rhombic central area.
Central Area contains a single stigma on one side of the central nodule.
Raphe distinctly lateral and somewhat sinuous. External proximal raphe ends narrow and bent towards the stigma. Terminal raphe ends are comma-shaped. From the central area towards the headpole,
striae are markedly radiate and sinuous, becoming parallel and straight close to the headpole. From the central area towards the footpole, striae are straight and slightly radiate. A longitudinal line interrupts the striae close to and on either side of the axial area.
Size RangeLength 34–58 µm.
Width 10.6–13.4 µm.
Striae in 10mm 13–15 at valve center; 15–16 at the apices.
Stigmata 1.
Useful Link:
Diatom Glossary [Diatoms of North America website]
Diagnostic Characteristics
Smaller than
Gomphadelpha septa with narrower ends and a narrower isthmus between valve body and footpole.
NOMENCLATURE & TAXONOMYGomphadelpha montana was previously placed into the genus
Gomphoneis (Bahls 2017).
Range Comments
Recorded from three locations in Montana: Flathead Lake, Hebgen Lake and Black Coulee NWR.
Type Locality
Black Coulee National Wildlife Refuge, Blaine County, Montana
Number of Observations in Montana Diatom Collection Database (Bahls 1968-2019): 3;
Montana: 3
Habitat
Lakes, reservoirs and wetlands.
Ecology
Cool, alkaline waters with moderate nutrients and conductivity (Bahls 2023).
Water Chemistry
Data not available.
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, L. 2017. Cymbopleura heilprinensis (Foged) Krammer and Gomphoneis montana Bahls: corrected names for two diatoms recently reported from western North America. Notulae algarum No. 25. ISSN 2009-8987.
- Bahls, Loren. 1968-Present. Montana Diatom Collection Database. Missoula, Montana.
- Bahls, Loren. 2023. Diatoms of Montana and western North America: Catalog and atlas of species in the Montana diatom collection Volume 2. The Academy of Natural Sciences of Philadelphia Special Publication 27. 600pp.
- Web Search Engines for Articles on "A Diatom"
