Diatoms of North AmericaDiatoms of North America

Encyonopsis stafsholtii

Bahls 2013

Encyonopsis Stafsholtii Guide
  • Category
    Asymmetric Biraphid
  • Length Range
    24.9-44.7 µm
  • Width Range
    5.1-6.3 µm
  • Striae in 10 µm
    22-25
  • Reported As
    Encyonopsis cesatii (Lange-Bertalot and Genkal 1999, p. 226, pl. 56, fig. 6)
    Cymbella cesatii (Tynni 1978, p. 27 [in part], pl. X, figs. 80 a, b [not figs. 79, 81])
    Cymbella cesatii (Krammer and Lange-Bertalot 1986, p. 325 [in part], pl. 134, fig. 6 [not figs. 4, 5, 7-13])

Identification

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

Description

Valves are rhombic-lanceolate and slightly dorsiventral. Apices are gradually protracted, narrowly subrostrate and deflected ventrally. The axial area is narrow. The central area is asymmetric, rounded on the dorsal side and delimited by 1 to 3 irregularly shortened striae on the ventral side. The raphe is lateral, becoming filiform at the proximal and distal ends. Proximal raphe ends are weakly expanded and deflected dorsally. Distal raphe fissures are hooked toward the ventral side. Striae are radiate throughout.

Autecology

Encyonopsis stafsholtii is widely distributed and locally abundant in lakes of the Northern Rockies. At sites with water quality data, pH ranges from 7.94 to 9.01 and conductivity from 92 to 171 µS/cm.

Lake Mc Donald April 12 2007
Credit: National Park Service webcam
Lake McDonald, Glacier National Park, Montana: type locality of Encyonopsis stafsholtii.

Original Description

Valves rhombic-lanceolate, slightly dorsiventral. Apices gradually protracted, narrowly subrostrate, deflected ventrally. Valve length 24.9–44.7 µm; valve width 5.1–6.3 µm. Axial area narrow. Central area asymmetric, rounded on the dorsal side, defined by 1 to 3 irregularly shortened striae on the ventral side. Raphe lateral, filiform at the proximal and distal ends. Proximal raphe ends weakly expanded, deflected dorsally. Distal raphe fissures hooked toward the ventral side. Striae radiate, 22–25 in 10 µm.

  • Author
    Bahls 2013
  • Length Range
    24.9-44.7 µm
  • Width
    5.1-6.3 µm
  • Striae in 10µm
    22-25

Original Images

Encyonopsis stafsholtii orig illus
Encyo Stafsholtii Origdesc004

Cite This Page

Bahls, L. (2013). Encyonopsis stafsholtii. In Diatoms of North America. Retrieved November 17, 2024, from https://diatoms.org/species/encyonopsis_stafsholtii

Responses

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