• Category
  • Length Range
    22.5-44.3 µm
  • Width Range
    6.2-8.5 µm
  • Striae in 10 µm
  • Reported As
    Nitzschia sinuata (Krammer and Lange-Bertalot 1988, p. 52, fig. 40: 1-4.)



Valves are linear-lanceolate, with triundulate margins and capitate apices. Fibulae are very large, occupy about one-half the valve face, and number 3-7 in 10 µm. Striae are distinctly punctate and weakly radiate. The raphe appears to be continuous through the central valve, as the central fibulae lack a distinctive gap. (Note that some authors express this feature by stating that the "central nodule is absent").


This taxon is uncommon in the benthos of shallow calcareous lakes and ponds of the northern Rocky Mountains. Here it is found at pH values ranging from 8.50 to 9.05 and specific conductance levels ranging from 105 to 181 µS/cm.

Lower  Wolverine  Pond 3
Credit: Loren Bahls
Lower Wolverine Pond, Ten Lakes Scenic Area, Kootenai National Forest, Lincoln County, Montana: home of Nitzschia sinuata var. sinuata.

Original Description

  • Basionym
    Denticula sinuata
  • Author
    Thwaites in W.Sm. 1856


Feb 13, 2020 - Recognition of Grunowia

This taxon was originally described as Grunowia sinuata (Thwaites) Rabenhorst 1864. It appeared as Nitzschia sinuata on this website from January 2014 until February 2020. - S. Spaulding

Cite This Page

Bahls, L. (2014). Grunowia sinuata. In Diatoms of North America. Retrieved July 19, 2024, from https://diatoms.org/species/grunowia_sinuata


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