Diatoms of North AmericaDiatoms of North America

Pinnularia pseudoparva

Krammer and Lange-Bert. 1999

Pinnularia pseudoparva guide
  • Category
    Symmetric Biraphid
  • Length Range
    22-31 µm
  • Width Range
    5.4-6.4 µm
  • Striae in 10 µm
    9-10

Identification

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

Valves are linear-elliptic, with bluntly rounded, subcapitate apices. The raphe is filiform. The proximal raphe ends are laterally deflected. Striae are thick and parallel, to slightly radiate in the center valve. Striae are parallel to slightly convergent at the valve apices. The axial area is moderately broad, with a distinct asymmetric widening near the center valve.

Autecology

Pinnularia pseudoparva is found in subarctic, oxygen-rich, soft waters. It was described from Siberia (Lange-Bertalot and Genkal 1999) and has been reported from additional sites in Siberia. Specimens shown on this page were found in Alaskan material of Patrick and Freese (1961).

Original Description

Valvae fere lineares, tumidae in media parte, margine recta, apicibus late protractis et rotundatis, 31 µm longae, 7 µm latae. Raphe vix lateralis, poris centralibus bulbiformibus, ad latus inclinatis, fissuris terminalibus semicircularibus. Area axialis ad nodulum centralem versus dilatata, lanceolata, area centralis lata ad margines valvae extendens.

Striae transapicales parallelae vel vix radiatae in media parte valvae, circiter 9 in 10 µm, lineae longitudinales nullae.

  • Author
    Krammer and Lange-Bert. 1999
  • Length Range
    31 µm
  • Width
    7 µm
  • Striae in 10µm
    9

Original Images

Pinnularia pseudoparva orig illus
Pinnularia pseudoparva orig desc

Cite This Page

Leppik, S., Potapova, M. (2024). Pinnularia pseudoparva. In Diatoms of North America. Retrieved January 18, 2026, from https://diatoms.org/species/327846/pinnularia-pseudoparva

Responses

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