• Category
  • Length Range
    26.0-38.0 µm
  • Width Range
    6.0-8.0 µm
  • Striae in 10 µm
    24-26 at the center, 28-30 at the ends



Valves with slightly rostrate, rounded apices, 26.0 - 38.0 µm in length by 6.0 - 8.0 µm in breadth. Valve mantle of moderate depth. The two raphe branches are arched along their entire length, resulting in asymmetrical valve face ornamentation. The distal raphe ends begin more or less centered along the longitudinal axis, and the raphe curves unilaterally toward the dorsal margin as it approaches the central area. The external proximal raphe ends are deflected in the same direction as the curve of the raphe branches. Enlarged poroids occur near the external distal raphe ends, positioned within a transverse depression. Striae are composed of rows of round, although commonly elongate, areolae. Areolae are internally occluded. The valvocopula is closed, and includes a row of projections on the internal side and a rough external notch near the center of the band. The notch is of varying size and shape and exposes a series of alternating poroids and small protuberances. In addition to the valvocopula, four open copulae are present, each with two rows of poroids.


Original Description

  • Basionym
    Navicula creuzburgensis
  • Author
    Krasske 1927
  • Length Range
    30.0-45.0 µm
  • Width
    6.0-8.0 µm
  • Striae in 10µm

Original Images

Krasske Illust

EMAP Assessment

EMAP Distribution

Frustulia Crassinervia 40 Copy 1
Map 40

Response Plots

Frustulia Crassinervia Copy 1

Cite This Page

Graeff, C. (2011). Frustulia creuzburgensis. In Diatoms of North America. Retrieved June 22, 2018, from https://diatoms.org/species/frustulia_creuzburgensis


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