Diatoms of North AmericaDiatoms of North America

Pinnularia lacunicola

Patrick and Freese 1961

Pinnularia lacunicula guide
  • Category
    Symmetric Biraphid
  • Length Range
    33-55 µm
  • Width Range
    6.6-10.2 µm
  • Striae in 10 µm
    11-15
  • Reported As
    Pinnularia krammeri (Krammer 2000, pg. 52, figs 12: 1-10, 20, 21)
    Pinnularia subrostrata (Krammer and Lange-Bertalot 1986, pg. 419, Pl. 185, Fig 18)

Identification

Pinnularia lacunicola LM5 Pinnularia lacunicola LM1 Pinnularia lacunicola LM2 Pinnularia lacunicola LM3 Pinnularia lacunicola LM6 Pinnularia lacunicola LM4 Pinnularia lacunicola LM7
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Description

Valves are linear-elliptic, with central valve margins that are slightly concave (in some specimens). The apices are slightly protracted and obtusely rounded. The raphe is filiform, with teardrop-shaped proximal raphe ends that are slightly deflected to one side. The axial area is narrow. The central area is rhombic central and expanded into a bow-tie shaped fascia that extends to the valve margin. Striae are strongly radiate in the center and convergent toward the apices.

It is important to note that the authors of this page consider that Pinnularia krammeri Metzeltin is a junior taxonomic (heterotypic) synonym of P. lacunicola.

Furthermore, the authors consider that specimens illustrated as Pinnularia subrostrata (Krammer and Lange-Bertalot 1986, fig. 185:18) and Pinnularia krammeri (Krammer 2000, figs 12: 1-10, 20, 21) belong to P. lacunicola.

Autecology

Patrick and Freese (1961) described this taxon from Alaskan sites that ranged from freshwater to brackish. For example, their Station 42 sample was collected near a mass of floating Spirogyra. Their reported water chemistry values include: pH 7.9, alkalinity 110 ppm (as CaCO3), chloride 82 ppm, total iron 0.34 ppm, water temperature 13 C. Their Station 23 sample was collected from a mass of sphagnum, grass, and algae near edge of small tundra pool, 3" deep. The algae included with euglenoids, rotifers, desmids, filaments of blue-green and green algae, and diatoms. Their reported water chemistry values include: pH 6.0, alkalinity 14 ppm (as CaCO3), hardness 30 ppm (as CaCO3), chloride 47 ppm, total iron 0.3 ppm, water temperature 4 C.

In more modern collections, this taxon was reported from Nordic oligotrophic and electrolyte-poor waters (Krammer 2000).

Original Description

Valva lineari, marginibus triundulatis leniter et apicibus truncatis et rotundis late. Area axiali angusta ad apices, amplificante gradatim in aream latam quae conjungit cum area media formare fasciam latam, transversam. Raphe undulata, fissuris terminalibus magnis et distinctis. Stris radiatis valide in media parte valvae et convenientibus ad apices. Striis, 10-13 in 10. Longitudo, 51-58 µ. Latitudo, 8-10 µ.

  • Author
    Patrick and Freese 1961
  • Length Range
    51-58 µm
  • Width
    8-10 µm
  • Striae in 10µm
    10-13

Original Images

Pinnularia lacunicola orig illus
Pinnularia lacunicola orig desc

Cite This Page

Leppik, S., Potapova, M. (2024). Pinnularia lacunicola. In Diatoms of North America. Retrieved April 22, 2025, from https://diatoms.org/species/328943/pinnularia-lacunicola

Responses

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