• Category
  • Diameter
    24.9-54.7 µm
  • Width Range
    3.4-4.5 µm
  • Striae in 10 µm
    16-17 based on circumferential density, 5-6 based on chord count



Valves are round. The central area covers 4/5 of the valve face. The central area is tangentially undulate, a feature more distinct in smaller specimens. The central area contains numerous central fultoportulae, arranged in a loosely circular pattern offset from the valve center. Striae are multiseriate composed of 3 to 4 rows of areolae. Radial "ghost" lines continue from the ends of the striae toward the valve center, where they become less pronounced. These lines may be slightly wavy, with occasional branching. The lines occur at a similar density as the striae. Spines are present between each stria at the face-mantle junction. Spines are 2-3 µm in length.


Cyclotella quillensis was described from the saline Big and Little Quill Lakes of Saskatchewan, Canada. This taxon was found co-occuring with brackish to marine taxa, including Chaetoceros, Pleurosigma elongatum and Thalassionema nitzschioides (Bailey 1922). Cyclotella quillensis has been reported from other saline lakes in the Great Plains region including Medicine Lake, South Dakota (Battarbee et al. 1984). It was found in a range of conditions: conductivity 7000-63,000 µS, salinity 7.2-102.8 ppt, pH 8.2-9.2, Ca 13-410 mg/L, Mg 30-10,454 mg/L, Na 571-11,413 mg/L, K 128-1252 mg/L, alkalinity 315-1940 mg/L, SO4 2785-59,553 mg/L, Cl 166-11,413 mg/L. Cyclotella quillensis has been used as a indicator of dry climatic periods, when precipitation is at a minimum and closed basin lakes become increasingly saline (Fritz et al. 1991).

Original Description

Valves circular, in the form of low vaulted domes, of which the surface is sometimes undulated. The size varies from 50 to 70 micron. Striae radiant as in Cyclotella compta, but arranged in three or four concentric circles, of which the outer has the character of ribs rather than striae, being strong and more or less distinctly pearled, while the second is much fainter and the third is only visible with high powers. Even a fourth circle can sometimes be made out, approaching the apex of the low zone. The number of marginal ribs is about 6 in 10 microns, and from these, in many cases, spring spines from one to two microns long, thus bearing a close resemblance to Stephanodiscus. Minute nodules are sometimes visible at the inner end of the second, third or fourth one of radiating striae. The centre of the dome is usually smooth, but sometimes shows a number of dots irregularly arranged. The species is larger than C. Kutzingiana or C. compta, being more like C. Meneghiniana. The marginal radial ribs look as if they might have been developed from striae originating like those of S. astrea or S. Niagarae, while the fainter second circle is not continuous with these, but appears to spring from an inter-rib depression.

  • Author
    L.W.Bailey 1922
  • Length Range
    50-70 µm
  • Striae in 10µm

Original Images

Cyclotella quillensis orig illus
Cyclotella quillensis orig descr

Cite This Page

Edlund, M., Burge, D. (2016). Cyclotella quillensis. In Diatoms of North America. Retrieved July 19, 2024, from https://diatoms.org/species/cyclotella_quillensis


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