• Category
  • Length Range
    40.7-48 µm
  • Width Range
    5.8-6.8 µm
  • Striae in 10 µm
    12
  • Reported As
    Pinnularia subcapitata (Camburn and Charles 2000)

Identification

Description

Valve outline is narrowly linear-lanceolate to rhombic-lanceolate with an occasionally swollen middle region. Apices are capitate and broadly rounded. The central area is asymmetric. Axial area is narrow and linear to linear-lanceolate. The raphe is filiform with weakly curved outer fissures, small rounded central pores, and ?-shaped terminal fissures. Striae are radiate in the center, becoming convergent towards the apices.

Specimens seen in Northeastern North America appear to be a little bit smaller and wider than in the original description.

Autecology

Pinnularia gibbiformis is commonly found in lakes.

Pinnularia gibbiformis ANSP GC112464a 01
Sheeler Lake, FL
Pinnularia gibbiformis ANSP GC112464a 03
Sheeler Lake, FL

Original Description

Merkmale Quant.: Lange 34-84 µm / Breite 5,8-8,5 µm / Str. 10-13/10 µm / 1/b bei den längsten Exemplaren 10-12.

Umriß: Schmal linear-lanzettlich, sich von der Mitte zu den Enden kontinuierlich verschmälemd oder mit fast geraden bis etwas welligen Seiten.

Enden: Stets deutlich abgesetzt und vorgezogen, zumeist aber kopfig, die Köpfchen fast so breit wie die Schale, Pole deutlich keilförmig gerundet.

Areae: Axialarea zumeist eng, linear, oder zur Mitte bin lanzettlich sich erweitemd; Zentralarea, deutlich von der Axialarea abgesetzt, länglichelliptisch, Breite b/2 bis fast an den Rand reichend, seltener eine Fascia.

Raphe: Lateral mit leicht gewelltem Außenspalt; Zentralporen klein, rund, nahe stehend, Endspalten deutlich, fragezeichenförmig.

Streife n: r/k-kk; Längslinien im LM nicht sichtbar.

Diagnose

Merkmalskombination: Umriß! -1/b! -Areae

Ahnliche Taxa: P. gibba (1/b kleiner, große Areae, Zentralarea nicht abgesetzt, breiter als 9 µm). P. subgibba (Seiten fast gerade, Axialarea oft breiter als b/2).

  • Author
    Krammer 1992
  • Length Range
    34-84 µm
  • Width
    5.8-8.5 µm
  • Striae in 10µm
    10-13

Original Images

Pin gibbiformis orig desc

Cite This Page

Aycock, L. (2022). Pinnularia gibbiformis. In Diatoms of North America. Retrieved May 20, 2024, from https://diatoms.org/species/pinnularia-gibbiformis

Responses

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