Diatoms of North AmericaDiatoms of North America

Encyonopsis cesatii

(Rabenh.) Krammer 1997

Encyonopsis Cesatii Guide
  • Category
    Asymmetric Biraphid
  • Length Range
    22.0-38.8 µm
  • Width Range
    4.6-6.0 µm
  • Striae in 10 µm
    16-19 at the valve center, 21-22 near the apices
  • Reported As
    Cymbella cesatii (Krammer and Lange-Bertalot 1986, p. 325 [in part], pl. 134, figs. 11, 12)
    Cymbella cesatii (Patrick and Reimer 1975, p. 21 [in part], pl. 3, fig. 2)

Identification

Encyocesatii 1 Encyocesatii 2 Encyocesatii 3 Encyocesatii 4 Encyocesatii 5 Encyocesatii 6 Encyocesatii 7
View image metadata

Description

Valves are narrowly lanceolate and nearly symmetric with respect to the apical axis. Apices are subrostrate and deflected weakly toward the ventral side. The axial area is narrow. The central area is small and asymmetric, formed by 1-3 shortened striae on the ventral side. The raphe is weakly lateral. Proximal raphe ends are deflected toward the dorsal side. Terminal raphe ends are hooked toward the ventral side. Striae are radiate throughout. Areolae are very fine and difficult to resolve in LM.

The morphological range of E. cesatii presented follows the lectotype designated by Krammer (1997, p. 152, Tafel 182, figs. 1-9) and illustrated below. Note that both Krammer and Lange-Bertalot (1986) and Patrick and Reimer illustrate a broader range of varieties and species within E. cesatii (for example, E. stafsholtii and varities of E. cesatii) in their publications.

Autecology

Encyonopsis cesatii is common in small headwater lakes, ponds and springs in the northern Rocky Mountains, where it is often found among mosses. Here it prefers cold, circumneutral waters with low concentrations of nutrients and dissolved solids. In these habitats it is often found in association with Encyonopsis falaisensis. Patrick & Reimer (1975) report it from the New England states and the Great Lakes states. Krammer & Lange-Bertalot (1986) report it as a northern-alpine species and common in the Alps and Finland.

Kootenai Pond And Citadel Peaks 2
Credit: Loren Bahls
Kootenai Pond, Glacier National Park, Montana: home of Encyonopsis cesatii and Encyonopsis falaisensis.

Original Description

  1. N. Cesatii Rabenh. (T. VI F. 89) Fast wie N. aponina, aber weit schlanker und (2-2.5)/100 Mm. lang; die Nebenseiten zwar genau linealisch, aber immer breiter und an den abgerundet. Im Piedmonteschen.
  • Basionym
    Navicula cesatii
  • Author
    Rabenh. 1853
  • Length Range
    20-41 µm
  • Width
    5.4-6.0 µm
  • Striae in 10µm
    18-19

Original Images

Encyonopsis Cesatii Orig Image
Encyonopsis Cesatii Origimag001
Encyonopsis Cesatii Orig Text

Cite This Page

Bahls, L. (2013). Encyonopsis cesatii. In Diatoms of North America. Retrieved April 19, 2024, from https://diatoms.org/species/encyonopsis_cesatii

Responses

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