• Category
  • Length Range
    35-54 µm
  • Width Range
    7.9-12.7 µm
  • Striae in 10 µm
    15-20
  • Reported As
    Navicula sp. 6 PISCES fo. 1 (Cumming et al. 1995)
    Navicula sp. 6 PISCES fo. 2 (Cumming et al. 1995)

Identification

Description

Valves are linear-lanceolate to elliptic-lanceolate with subrostrate apices. Valves are strongly arched transapically; valve face and mantle are indistinguishable. Axial area is very narrow. Central area is small and irregular in shape; a distinct transverse fascia is lacking. Raphe is filiform with straight and slightly expanded proximal ends. Distal raphe ends are hooked in the same direction. Striae are weakly radiate at valve center to parallel or slightly convergent at the apices. Striae are irregularly shortened and more widely spaced near the center. Areolae are very fine and difficult to resolve in LM.

Frustules may occur with "Janus valves", two distinct morphologies within a single frustule. The description above refers to "normal" valves. In Janus valves, the central area is large and rounded. Proximal raphe ends are more distant than in normal valves. Striae are irregularly spaced.

Autecology

Staurophora columbiana has been collected from three shallow saline lakes on the Northwestern Great Plains in central Montana. The pH of these lakes measured a constant 9.20 and specific conductance ranged from 44100 to 67800 µS/cm.

Kingsbury Lake1
Credit: Loren Bahls
Kingsbury Lake, Chouteau County, Montana: holotype locality of Staurophora columbiana.
Kingsbury Lake2
Credit: Loren Bahls
Kingsbury Lake, Chouteau County, Montana: home of Staurophora columbiana.

Original Description

Valves linear-lanceolate to elliptic-lanceolate with subrostrate apices. Valves strongly arched in transapical axis; valve face and mantle indistinguishable. Valve length 35–54 μm; valve width 7.9–12.7 μm. Axial area very narrow. Central area small and irregular; transverse fascia lacking. Raphe filiform with straight and slightly expanded proximal ends. Terminal raphe fissures hooked in the same direction. Striae finely punctate, weakly radiate at valve center to parallel or slightly convergent at apices, 15–20 in 10 μm. Striae irregularly shortened and more widely spaced near valve center. Areolae difficult to resolve in LM. Janus valves present with large rounded central area, more distant proximal raphe ends, and more irregularly spaced striae.

  • Author
    L.L.Bahls 2013
  • Length Range
    35-54 µm
  • Width
    7.9-12.7 µm
  • Striae in 10µm
    15-20

Original Images

Staurophoracolumbiana Origimag012
Staurophoracolumbiana Origdesc011

Cite This Page

Bahls, L. (2012). Staurophora columbiana. In Diatoms of North America. Retrieved August 15, 2018, from https://diatoms.org/species/staurophora_columbiana

Responses

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