Diatoms of North AmericaDiatoms of North America

Encyonopsis anacondae

Bahls 2013

Encyonopsis Anacondae Guide
  • Category
    Asymmetric Biraphid
  • Length Range
    16.6-24.4 µm
  • Width Range
    3.2-4.0 µm
  • Striae in 10 µm
    25-28

Identification

Encyonopsis Anaconda1 Encyonopsis Anaconda3 Encyonopsis Anaconda2 Encyonopsis Anaconda4 Encyonopsis Anaconda5 Encyonopsis Anaconda6 Encyonopsis Anaconda7
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Description

Valves are narrowly linear to linear-lanceolate and slightly dorsiventral. Dorsal and ventral margins are weakly convex. The apices are rostrate and deflected slightly to the ventral side. The axial area is narrow and located near the apical axis. The central area is very small, barely wider than the axial area. The raphe is filiform. Proximal raphe ends are unexpanded and deflected toward the dorsal margin. Distal raphe fissures are hooked toward the ventral margin. Striae are weakly radiate to parallel.

Autecology

Encyonopsis anacondae is known only from Upper Seymour Lake in the Anaconda Range of southwest Montana (photo below). Upper Seymour Lake lies at an elevation of 2512 m and has circumneutral water with low dissolved solids.

Upper Seymour Lake
Credit: panoramio.com
Upper Seymour Lake, Anaconda-Pintler Wilderness, Deer Lodge County, Montana: type locality of Encyonopsis anacondae.

Original Description

Valves narrowly linear to linear-lanceolate, slightly dorsiventral. Dorsal and ventral margins weakly convex. Valve length 16.6–24.4 µm; valve width 3.2–4.0 µm. Apices rostrate, deflected slightly to the ventral side. Axial area narrow, near valve median line. Central area very small, barely wider than the axial area. Raphe filiform. Proximal raphe ends unexpanded, deflected toward the dorsal margin. Distal raphe fissures hooked toward the ventral margin. Striae weakly radiate, 25–28 in 10 µm.

  • Author
    Bahls 2013
  • Length Range
    16.6-24.4 µm
  • Width
    3.2-4.0 µm
  • Striae in 10µm
    25-28

Original Images

Encyo Anacondae Origimag Cropped
Encyo Anacondae Origidesc001

Cite This Page

Bahls, L. (2013). Encyonopsis anacondae. In Diatoms of North America. Retrieved April 24, 2024, from https://diatoms.org/species/encyonopsis_anacondae

Responses

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