• Category
  • Length Range
    139-274 µm
  • Width Range
    29-45 µm
  • Striae in 10 µm
  • Reported As
    Navicula cuspidata var. major (Patrick and Reimer 1966, p. 465, plate 44, fig. 1)



Valves are very large and lanceolate with blunt, broadly rounded apices. The axial area is linear and barely wider than the raphe. The central area is slightly wider than the axial area and with straight or somewhat convex sides. The raphe is weakly lateral with moderately inflated proximal ends that bend slightly to one side. Distal raphe ends are hooked toward the same direction. Striae are parallel in the center, becoming weakly convergent and then weakly radiate near the apices. Areolae may be distinguished in LM and number 20-24 in 10 µm.

Meister (1912) described a taxon from Switzerland as Navicula cuspidata var. major, which Patrick & Reimer (1966) report from Ohio. It is not clear if these two taxa are conspecific.


Craticula pampeana has been recorded from 7 prairie streams and wetlands in eastern Montana, where the water is alkaline and rich in sodium and sulfate with elevated dissolved solids (see table below). Here it is most frequently associated with Navicula rhynchotella, Nitzschia subvitrea, Planothidium engelbrechtii, Craticula buderi, Anomoeoneis costata, and Nitzschia commutatoides. This species was described from material collected in Argentina (Frenguelli 1926). It has also been reported (as Navicula cuspidata var. major) from Switzerland (Meister 1912) and Ohio (Patrick & Reimer 1966).

Poplar  River 1
Credit: Loren Bahls
Poplar River, eastern Montana: home of Craticula pampeana.
Cratpamp Chemistry
Credit: Montana Diatom Database
Abundance-weighted means of selected water quality variables measured concurrently with the collection of diatom samples containing Craticula pampeana.

Original Description

  • Basionym
    Navicula pampeana
  • Author
    Freng. 1926
  • Length Range
    95-264 µm
  • Width
    23-45 µm
  • Striae in 10µm

Original Images

 Navicula pampeana orig illus
Navicula pampeana orig illus 2
Navicula pampeana orig illus
Navicula pampiana orig descr

Cite This Page

Bahls, L. (2012). Craticula pampeana. In Diatoms of North America. Retrieved June 19, 2018, from https://diatoms.org/species/craticula_pampeana


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