• Category
  • Length Range
    61-79 µm
  • Width Range
    9-10 µm
  • Striae in 10 µm
  • Reported As
    Pinnularia gibba var. linearis (unspecified - see Krammer 2000)



Valves are linear, with parallel valve margins. The apices are broadly rounded and, in some specimens, slightly swollen. The axial area is about 1/3 the valve width and widens to an irregularly rhombic central area with a broad transverse fascia. In the central area of some specimens, four indistinct markings are visible. The raphe is broadly lateral with question mark-shaped terminal fissures. Striae are radiate in the center, becoming convergent toward the ends.


This taxon was described from a lake in Massachusetts. Images here are from lake sediments of New Jersey and New York.

Original Description

87.3 Pinnularia subgibba var. sublinearis nov. var. [Figs 65: 14]
Type locality: Waltham, Massachusetts, USA, slide 2009 NW.
Outline linear with parallel sides and not differentiated, rounded ends; length 60-80 µm, breadth 9-11, 8-9 striae/10 µm.
Distribution: Rare, commonly sporadic in boreal, more frequent in fossil samples. Some records in the literature under the name "P. gibba var. linearis" belong to this taxon.

  • Author
    Krammer 2000
  • Length Range
    60-80 µm
  • Width
    9-11 µm
  • Striae in 10µm

Original Images

Pinn subgibba var sublinearis org img
Pinn subgibba var sublinearis org descrp

Cite This Page

Aycock, L. (2022). Pinnularia subgibba var. sublineairs. In Diatoms of North America. Retrieved June 17, 2024, from https://diatoms.org/species/pinnularia-subgibba-var-sublinearis


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