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A Diatom - Navicula whitefishensis
General Description
Morphological Category – Symmetric biraphid
Valves broadly lanceolate with narrow, abruptly protracted, subcapitate apices.
Axial Area narrow, widening gradually towards a large, rounded central area.
Central Area is 6-8 µm in diameter.
Raphe is filiform to weakly lateral. Proximal raphe ends expanded and weakly deflected to one side. Terminal raphe fissures curved, opening towards the secondary side.
Striae strongly radiate throughout most of valve, becoming parallel then convergent near the apices.
Areolae 28-30 in 10 µm.
Size RangeLength 46-60 µm.
Width 11.3-14.2 µm.
Striae in 10 µm 12-14.
Useful Link:
Diatom Glossary [Diatoms of North America website]
Diagnostic Characteristics
The large, rounded central area and the narrow, capitate apices of
Navicula whitefishensis are distinctive.
Navicula trivialis valves and central areas are both smaller than
N. whitefishensis.
Navicula oligotraphenta is smaller than
N. whitefishensis and
N. trivialis. Striae of Navicula hasta are strongly radiate, but are more irregular near the center of the valve. Apices of
N. hasta are not as narrow.
Range Comments
Recorded from Upper Whitefish Lake and East Fork Swift Creek, Flathead County, and Redrock Lake, Glacier National Park.
Type Locality
Upper Whitefish Lake, Flathead County, Montana
Specimen housed at the University of Montana Herbarium (MONTU)
Number of Observations in Montana Diatom Collection Database (Bahls 1968-2019): 3;
Montana: 3
Habitat
Headwater lakes and streams.
Ecology
Cold, circumneutral water with very low nutrients and conductivity.
Water Chemistry
Upper Whitefish Lake: pH = 7.4; conductivity = 130 µS/cm a
Redrock Lake: pH = 7.1; conductivity = 94 µS/cm
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. 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.
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