• Category
  • Length Range
    109-221 µm
  • Width Range
    24-34 µm
  • Striae in 10 µm
    13-15
  • Reported As
    Stauroneis javanica (Krammer and Lange-Bertalot 1986)
    Stauroneis javanica (Hustedt 1959)
    Stauroneis javanica (Molder and Tynni 1973)

Identification

Description

Valves are broadly lanceolate with gradually attenuated subrostrate apices. A prominent pseudoseptum is present at each apex. The axial area is broad, about three times the width of the raphe, and becomes somewhat wider near the central area. The central area is a nearly rectangular stauros, only slightly wider at the valve margins. Raphe fissures are lateral, becoming reverse lateral and strongly curved near the large, proximal pores. Distal raphe fissures are hooked toward the secondary side. Striae are radiate throughout. Areolae are coarse and number 12-15 in 10 µm.

Autecology

In the Northern Rockies, Stauroneis finlandia has been found in three small ponds and fens in western Montana. Measured pH at the type locality (Johns Fen, Glacier National Park) was 6.0 and specific conductance was 58 µS/cm.

Dscn2204
Credit: Billy Schweiger, National Park Service
Starvation Ridge Pond, Glacier National Park, Montana: home of Stauroneis finlandia.

Original Description

Valves broadly lanceolate with gradually attenuated subrostrate ends. Length 110-221 µm, width 25-34 µm. A prominent pseudoseptum is present at each apex. Axial area broad, expanding in deltoid fashion into the central area. Central area a nearly rectangular fascia, only slightly wider at the valve margins. Raphe fissures lateral, becoming reverse lateral and strongly curved near the large central pores. Distal raphe fissures hooked toward the secondary side. Striae radiate, 13-15 in 10 µm. Striae puncta 12-15 in 10 µm. For measurements, n = 24 valves.

  • Author
    L.L.Bahls 2010
  • Length Range
    110-221 µm
  • Width
    25-34 µm
  • Striae in 10µm
    13-15

Original Images

Sfin Origimage
Sfin Origdesc

Cite This Page

Bahls, L. (2011). Stauroneis finlandia. In Diatoms of North America. Retrieved July 22, 2018, from https://diatoms.org/species/stauroneis_finlandia

Responses

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