• Category
  • Length Range
    64.9-117.9 µm
  • Width Range
    8.8-11.3 µm
  • Striae in 10 µm
  • Reported As
    Eunotia parallela (Krammer and Lange Bertalot 1991, pg. 208, Pl. 152, Fig 4-7)



Valves are arcuate. The ventral and dorsal margins, while curved, are parallel. The valves may have a very shallow distal depression in the dorsal margin near the apex. Apices are broadly rounded.

The terminal raphe fissures hook over the ventral margin of the apices, appearing like short curves deflected toward the dorsal side, near the distal valve face. Helictoglossae are visible, appearing as a darkened area on the ventral side near the valve end.

Striae near the apices are irregular and radiate slightly about the raphe. Striae are fine and perpendicular to the valve margin. The striae are fairly regularly spaced in proximal parts of the valve. Striae may be interrupted by the sternum near the ventral margin. Areolae are distinct and number 27-30 in 10 µm.


This taxon was found in a periphyton sample from a protected minerotrophic peatland as part of a study conducted in three fens (a rich, moderate, and poor) located within a wetland complex in the
Tanana River floodplain outside the Bonanza Creek Experimental Forest (35 km southeast of Fairbanks) in interior Alaska.

We defined the peatland types following Rydin and Jeglum (2013) which described moderate fens as having a pH range of 5-7 and are moderately rich in dissolved minerals and vegetation diversity, including sedges and brown mosses with sparsely distributed Sphagnum moss and poor fens as peatlands with extremely low concentrations of dissolved minerals dominated by Sphagnum moss species capable of acidifying the surrounding environment (pH 4–5.5) thereby inhibiting many vascular plants. The moderate fen in which E. pseudoparallela was most frequently encountered was composed of both brown moss and Sphagnum species, with less dense vegetation of C. atherodes, E. fluviatile, and P. palustris. The poor fen was primarily composed of Sphagnum species with sparsely distributed E. fluviatile, P. palustris, and Eriophorum vaginatum with a mean pH of 5.77 during the sampling season (May-August 2017), where E. pseudoparallela was still observed but less frequently encountered. Eunotia pseudoparallela is considered to be very rare or not documented in central and southern Europe, fairly rare in most regions of the Holarctic, and abundant in Scandinavia (Lange-Bertalot et al. 2011).

Poor fen zoom
Credit: Kevin H. Wyatt
Sample site and substrates within a sphagnum dominated peatland, near Bonanza Creek LTER, Alaska, USA
Moderate fen zoom

Original Description

  • Author
    A.Cleve 1934

Cite This Page

Hamilton, V. (2022). Eunotia pseudoparallela. In Diatoms of North America. Retrieved October 03, 2023, from https://diatoms.org/species/eunotia-pseudoparallela


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