• Category
  • Length Range
    32-59 µm
  • Width Range
    10.5-12.0 µm
  • Striae in 10 µm
    9-12 in the valve center, 12-14 near the apices



The ventral margin is concave. The dorsal margin is broadly arched. The dorsal margin of smaller valves are more arched than the dorsal margin of larger valves. The apices are broadly rounded and usually unconstricted, though slightly constricted in the longer valves. The apices are set off by a change in slope of the dorsal margin. Helictoglossae are visible in the LM. One apical rimoportula is present at the center of the apex. Striae are mostly parallel and interrupted by a hyaline line at the ventral margin. Areolae are 28-30 in 10 µm.

Comparison of E. areniverma with E. monodon deserves further clarification. Siver et al. (2005, Plate 31: Figs 1- 4) illustrates specimens of E. monodon Ehrenberg which also possess broadly rounded ends. The dorsal margin becomes more sloped, with a more pronounced hump as frustules decrease in size. However, based on the original description, E. monodon has apices with more cuneate ends, such as the E. monodon illustrated in Patrick & Reimer (1966, Plate 11: Fig. 6) and Lange-Bertalot (1993, Taf. 22: Figs 6 -7). Eunotia monodon was described from North America and is found here along with E. monodontiforma Lange-Bertalot et Nörpel. When the name was adopted in Europe, it was used incorrectly to describe what should be E. major (W. Smith) Rabenhorst (see discussion in Lange-Bertalot 1993). This has created some confusion around the taxonomy of the E. monodon and the E. major groups. The ends of both E. major and E. monodontiforma are more set off from the rest of the valve relative to E. areniverma. The broadly rounded ends, less set off from the rest of the valve and the broadly arching dorsal margin are characteristic features of E. areniverma.


Currently only known from a bryophyte squeeze in a soil seep at a rock outcrop at the bottom of a dry water way along the Long Hungry Ridge Trail off the 20 – Mile Creek Trail in the Great Smoky Mountains National Park.

Original Description

Valves concave on the ventral margin, convex on the dorsal margin with a central swelling, prominently swollen in smallest valves, 32-59 μm long, 10.5-12.0 μm wide. Ends broadly rounded, usually unconstricted, slightly constricted in longest valves, set off by a change in slope of the dorsal margin. Helictoglossae visible in light microscope. Rimoportula at one end of valve, at the center of the apex. Striae mostly parallel, interrupted by a hyaline line at the ventral margin, 9-12 in 10 μm in the valve center, 12-14 in 10 μm near the valve apices. Puncta 28-30 in 10 μm.

  • Author
    Furey, Lowe and Johansen 2011
  • Length Range
    32-59 µm
  • Width
    10.5-12.0 µm
  • Striae in 10µm
    9-12 in the center valve, 12-14 near the valve apices

Original Images

Eunotia areniverma orig illus
Eunotia Areniverma Textscan

Cite This Page

Furey, P. (2011). Eunotia areniverma. In Diatoms of North America. Retrieved June 23, 2018, from https://diatoms.org/species/eunotia_areniverma


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