• Category
  • Length Range
    93-137 µm
  • Width Range
    14-20 µm
  • Striae in 10 µm
    21-24
  • Reported As
    Stauroneis cf. gracilis (Metzeltin and Witkowski 1996)

Identification

Description

Valves are narrowly lanceolate with subtly protracted and broadly rounded apices. The axial area is narrow and linear, widening somewhat towards the central area. The stauros is a bit wider near the valve margins than at the center. One to three short striae are usually present on each side of the central area. Raphe fissures are lateral and the proximal ends are nearly straight. The proximal raphe pores are very small. Each raphe branch becomes filiform just short of the terminal fissures. Terminal raphe fissures are hooked towards the secondary side. The striae are radiate and strongly radiate near the apices. Areolae are fine and number 18-22 in 10 µm.

Autecology

Stauroneis beeskovea has been found in six small lakes in western Montana. In these waters pH ranges from 6.6 to 8.0 and specific conductance ranges from 10 to 67 µS/cm. Metzeltin & Witkowski (1996) published a photo of a similar and perhaps conspecific specimen from Bear Island in the North Atlantic (Stauroneis cf. gracilis Ehrenberg, Tafel 10, fig. 4, without diagnosis).

Beeskove  Lake
Credit: Google Earth
Beeskove Lake (right), Rattlesnake Wilderness, Missoula County, Montana: type locality of Stauroneis beeskovea.

Original Description

Valves narrowly lanceolate, ends subtly protracted and broadly rounded. Length 93-137 µm, width 14-20 µm. Length to width ratio: 6.5-7.7. Axial area narrow, linear, widening near the central area. Central area a narrow transverse fascia, widening slightly toward the valve margins. One to three shortened striae often present on each side. Raphe fissures lateral, proximal endings nearly straight, bent slightly toward the secondary side. Central pores very small, slightly inflated. Terminal raphe fissures hooked toward the secondary side. Striae radiate, quickly becoming very steeply radiate toward the ends, 21-24 in 10 µm. Striae puncta fine, 18-22 in 10 µm. For measurements, n = 24 valves.

  • Author
    Bahls 2010
  • Length Range
    93-137 µm
  • Width
    14-20 µm
  • Striae in 10µm
    21-24

Original Images

Sbeesk Origimag1
Sbeesk Origimag2
Sbeesk Origdesc

Cite This Page

Bahls, L. (2011). Stauroneis beeskovea. In Diatoms of North America. Retrieved July 17, 2018, from https://diatoms.org/species/stauroneis_beeskovea

Responses

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