Credit: USGS Biodata
Pinnularia formica occurence in river surveys by USGS.
Pinnularia formica
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Category
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Length Range84-162 µm
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Width Range12-18 µm
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Striae in 10 µm8-9
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SynonymsPinnularia nodosa var. formica (Ehrenb.) Cleve
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ContributorMeredith Tyree Polaskey, Hayden Ripple - Jan 2018
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ReviewerSarah Spaulding - Mar 2018
Identification
Description
Valves with a large expanded central valve and distinctly capitate apices. The center expansion of the valve is longitudinally elliptic. The striae are constrained to the margin of the valve face, creating a large axial area, up to roughly 2/3 of the valve face. Striae are weakly radiate to parallel near the central area, transitioning to convergent at the apices. Striae are longer near the apices. The raphe is lateral. Proximal raphe ends are deflected unilaterally and terminate in a teardrop shape. Within a frustule, the raphe of each valve are offset to one another. The distal ends of the raphe are strongly deflected toward the same side. Distal ends of the raphe terminate in a "question mark" shape.
Autecology
Pinnularia formica has been found in lentic and lotic freshwater systems along the east coast of the US. The specimens shown here were found in surface sediments of lakes in the northeast.
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Size Range, µm3
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Motility
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Attachment
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Habitat
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Colony
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Occurrence
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Waterbody
- Learn more about this
Credit: www.CT.gov - Connecticut Department of Energy and Environmental Protection.
Halls Pond, Maine - a site where P. formica has been reprted.
Original Description
144 N. formica, testula a dorso anguste linearies quater constricta, articulis spuriis oblongis. Maine A, nec Bridgwater.
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BasionymNavicula formica
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AuthorEhrenb. 1843
Original Images
Citations & Links
Citations
Links
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Index Nominum Algarum
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North American Diatom Ecological DatabaseNADED ID: 52028
Cite This Page
Polaskey, M., Ripple, H. (2018). Pinnularia formica. In Diatoms of North America. Retrieved December 21, 2024, from https://diatoms.org/species/84110/pinnularia_formica
Responses
The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Pinnularia formica from all the stream reaches where it was present. Note that the relative abundance scale is the same on each plot. Explanation of each environmental variable and units are as follows:
ELEVATION = stream reach elevation (meters)
STRAHLER = distribution plot of the Strahler Stream Order
SLOPE = stream reach gradient (degrees)
W1_HALL = an index that is a measure of streamside (riparian) human activity that ranges from 0 - 10, with a value of 0 indicating of minimal disturbance to a value of 10 indicating severe disturbance.
PHSTVL = pH measured in a sealed syringe sample (pH units)
log_COND = log concentration of specific conductivity (µS/cm)
log_PTL = log concentration of total phosphorus (µg/L)
log_NO3 = log concentration of nitrate (µeq/L)
log_DOC = log concentration of dissolved organic carbon (mg/L)
log_SIO2 = log concentration of silicon (mg/L)
log_NA = log concentration of sodium (µeq/L)
log_HCO3 = log concentration of the bicarbonate ion (µeq/L)
EMBED = percent of the stream substrate that is embedded by sand and fine sediment
log_TURBIDITY = log of turbidity, a measure of cloudiness of water, in nephelometric turbidity units (NTU).
DISTOT = an index of total human disturbance in the watershed that ranges from 1 - 100, with a value of 0 indicating of minimal disturbance to a value of 100 indicating severe disturbance.
Pinnularia formica
- Central expansion distinct
- Apices capitate
- Striae constrained to valve margin
Valves are large. They have a distinct, longitudinally elliptic central expansion. Apices are expanded and capitate. The striae are constrained to the valve margin, so that the axial area covers most of the valve.