• Category
  • Length Range
    7-33 µm
  • Width Range
    7-19 µm
  • Striae in 10 µm
  • Synonyms
    Fragilaria leptostauron (Ehrenb.) Hust.



Valves are cruciform, 7-19 µm wide and 7-33 µm long. Valves with rounded ends. The central area is broad. The valve face is flat, or slightly undulate due to raised costae. The valve face/mantle junction forms a sharp angle. The abvalvar edge of the mantle is parallel to the valve face/mantle junction. In girdle view, frustules are rectangular. Cells form ribbon-like colonies, joined by linking spines. A cell within a colony is attached to the substratum by a mucilage pad, or cells may be planktonic. The axial area is linear to lanceolate. Striae are distinct, composed of lineolae. Lineolae are greatest in length midway between the sternum and valve mantle, 5-11 in 10 µm. Lineolae bear finely branched volae and may possess siliceous bridges between lineolae. Striae are parallel in the central area, becoming radiate near the valve ends. Striae extend onto the valve mantle. Costae are not as broad as the striae. Spines are flat, spatulate toward their ends and solid. Spines are present along the valve face edge, except at the apices, and are located on the costae between striae. Well-developed, ocellulimbus type, apical pore fields with round poroids are present. Pore fields are located at the junction between the valve face/mantle. Rimoportulae are absent. Copulae, or girdle bands, are closed and do not bear perforations. Valvocopulae are wider than other girdle elements and bear fimbriae (finger-like projections).


Cells are attached by mucilage pads to substrates and joined in colonies by linking spines.

Original Description

  • Basionym
    Biblarium leptostauron
  • Author
    Ehrenb. 1854

Original Images

S Leptostauron Iconotype

Cite This Page

Morales, E. (2010). Staurosirella leptostauron. In Diatoms of North America. Retrieved July 24, 2024, from https://diatoms.org/species/staurosirella_leptostauron


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