• Category
  • Length Range
    68-113 µm
  • Width Range
    15.6-19.5 µm
  • Striae in 10 µm
    14 (middle) to 18 (ends)
  • Reported As
    Craticula "silviae" (Lange-Bertalot 2001)
    Craticula (?) acidoclinata (Lange-Bertalot et al. 2003)



Valves are lanceolate with broadly rounded apices. The axial area is linear and narrow. The central area is elliptic with convex sides, and about two times wider than the axial area. The raphe is weakly lateral, with straight and slightly inflated proximal ends. Striae are parallel in the middle, becoming weakly radiate and then convergent near the apices. Areolae may be resolved in LM and number 26 in 10 µm.


Craticula sardiniana has been collected from two ponds in the northern Rocky Mountains where pH ranges from 7.8 to 11.1 and specific conductance ranges from 49 to 313 µS/cm. Its preference for alkaline waters with higher electrolyte content sets this taxon apart from Craticula acidoclinata, which prefers acidic or circumneutral waters with very low electrolyte content. Craticula sardiniana was first reported (as ? Craticula acidoclinata) from rock pools in Sardinia rich in electrolytes (Lange-Bertalot et al. 2003).

Indian  Springs  Ponds
Credit: Barb Johnston, Parks Canada
Indian Springs Ponds, Waterton Lakes National Park, Alberta, Canada: home of Craticula sardiniana.
Skinner  Pond 1
Credit: Loren Bahls
Skinner Pond No. 1, Beaverhead County, Montana: home of Craticula sardiniana.

Original Description

Valves lanceolate with broadly rounded, unprotracted apices. Valve length 68–113 μm; valve width 15.6–19.5 μm. Axial area linear and narrow. Central area elliptic with convex sides, about two times wider than axial area. Raphe weakly lateral with straight and slightly inflated proximal ends. Striae parallel in the middle, becoming weakly radiate, then convergent near the apices, 14 in 10 μm at the valve center to 18 in 10 μm near the apices. Areolae 26 in 10 μm. Craticula valves observed; “Heribaudii” valves not observed.

  • Author
    Bahls 2013
  • Length Range
    68-113 µm
  • Width
    15.6-19.5 µm
  • Striae in 10µm
    14 at valve center, 18 near the apices

Original Images

Craticula sardiniana orig illus
Craticula sardiniana orig descr

Cite This Page

Bahls, L. (2012). Craticula sardiniana. In Diatoms of North America. Retrieved June 24, 2018, from https://diatoms.org/species/craticula_sardiniana


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