Diatoms of North AmericaDiatoms of North America

Encyonopsis descripta

(Hust.) Krammer 1997

Encyonopsis Descripta Guide
  • Category
    Asymmetric Biraphid
  • Length Range
    25.7-29.9 µm
  • Width Range
    5.4-6.6 µm
  • Striae in 10 µm
    18-20 at valve center, 20-22 near the apices
  • Synonyms
    Cymbella descripta (Hust.) Krammer and Lange-Bert. 1985
  • Reported As
    Cymbella descripta (Krammer and Lange-Bertalot 1986, p. 327, figs. 135: 1-5)

Identification

Encyonopsis Descripta3 Encyonopsis Descripta7 Encyonopsis Descripta6 Encyonopsis Descripta1 Encyonopsis Descripta2
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Description

Valves are linear-lanceolate with capitate apices and not or only slightly dorsiventral. The axial area is narrow and positioned along the valve midline. The central area is large, round, and nearly symmetric. The raphe is weakly lateral, becoming filiform near the proximal and distal ends. Proximal raphe ends are weakly expanded and deflected dorsally. Distal raphe ends are curved toward the ventral side. Striae are radiate throughout.

Autecology

Encyonopsis descripta has been collected from a few remote lakes in the Northern Rockies. Here pH ranges from 7.0 to 8.2 and specific conductance from 64 to 250 µS/cm.

Lower Quartz Lake Wikimediaorg
Credit: wikimedia.org
Lower Quartz Lake, Glacier National Park, Montana: home of Encyonopsis descripta.

Original Description

  • Basionym
    Navicula descripta
  • Author
    Hust. 1943

Original Images

Navicula descripta orig illus

Cite This Page

Bahls, L. (2013). Encyonopsis descripta. In Diatoms of North America. Retrieved November 21, 2024, from https://diatoms.org/species/encyonopsis_descripta

Responses

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