• Category
  • Length Range
    130–215 µm
  • Width Range
    20-25 µm
  • Striae in 10 µm
    6-8

Identification

Description

Valves are linear, with straight or very slightly concave or triundulate sides, and length-to-width ratio 6–8.6. Valve apices are broadly rounded and slightly off-set in most specimens. Axial area is linear, 1/3–1/5 of the valve width. Central area is elliptic, asymmetrical, wider on primary valve side, often poorly differentiated from the axial area, barely or not expanded on the secondary valve side. Striae (alveoli) are weakly radiate at valve center and parallel at the apices. Internal areola openings are short, with their borders forming a visible line in LM, crossing the striae approximately in the middle. Raphe is lateral with weakly sinuous external slit, slightly expanded central pores and question mark-shaped terminal raphe fissures. Short spines are located on the valve face–mantle junction, on both sides of the valve, randomly placed on some virgae, with 2–5 virgae in between. Spines originate from round depressions and vary randomly in size and shape, from small conical, to larger flattened and bifurcated at the ends.

Autecology

This taxon is found across the eastern United States in lakes with a high range of pH (4.5–8.8), moderate range of conductivity (17–202 μS/cm), rather high total phosphorus (4–166 )μg/L and relatively low total nitrogen (988–1531) μg /L. This diatom shows a clear preference for soft-water lakes and a some tendency to occur in slightly acid waters of relatively low nutrient content.

Original Description

Pinnularia spinifera Potapova, Kersey & Aycock sp. nov. (Figs 45-56, 86, 87, 92-97)

Description. Valves linear, with straight or very slightly concave or triundulate sides, 22–25 μm wide, 130–215 μm long (Figs 45–56, 86, 87). Length-to-width ratio 6–8.6. Valve apices broadly rounded and slightly off-set in most specimens. Axial area linear, 1/3–1/5 of the valve width. Central area elliptic, asymmetrical, wider on primary valve side, often poorly differentiated from the axial area, barely or not expanded on the secondary valve side. Striae (alveoli) weakly radiate at valve centre and parallel at the apices, 6–7 in 10 μm throughout the valve, 7–8 in 10 μm around the central area. Internal areola openings short (Figs 94, 96), with their borders forming a visible line in LM, crossing the striae approximately in the middle (Figs 45–56, 86, 87). Raphe lateral with weakly sinuous external slit, slightly expanded central pores and question mark-shaped terminal raphe fissures (Figs 92, 93, 97). Short spines located on the valve face–mantle junction, on both sides of the valve, randomly placed on some virgae, with 2–5 virgae in between. Spines originate from round depressions and vary randomly in size and shape, from small conical, to larger flattened and bifurcated at the ends (Figs 93, 95).

  • Author
    Potapova, Kersey and Aycock 2023
  • Length Range
    30–215 µm
  • Width
    20-25 µm
  • Striae in 10µm
    6-8

Original Images

Pinnularia spinifera Orig Ill

Cite This Page

Potapova, M. (2023). Pinnularia spinifera. In Diatoms of North America. Retrieved April 16, 2024, from https://diatoms.org/species/pinnularia-spinifera

Responses

The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Pinnularia spinifera 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.