• Category
  • Length Range
    12-60 µm
  • Width Range
    10-16 µm
  • Striae in 10 µm
  • Synonyms
    Cystopleura musculus (Kütz.) Kuntze 1891
    Rhopalodia gibberula var. musculus (Kütz.) A.Cleve 1952
    Rhopalodia musculus (Kützing) O. Müller 1900



Valves of this species are semi-elliptic. Valves are strongly convex along the dorsal margin and concave along the ventral margin, tapering to narrowly rounded ends. The raphe is located in the canal along the dorsal margin. Distinct costae on the valve face number 3-5 in 10 µm. Striae form 2-4 rows between the costae.


Original Description

  • Basionym
    Epithemia musculus
  • Author
    Kütz. 1844

Original Images

Epithemia Musculus Orig Ill
Epithemia Musculus Orig Descr


May 16, 2020 - Revision to previous name

From 2011 to May 2020, this species appeared as Rhopalodia musculus Kütz., which had been its accepted name. Phylogenetic analysis of diatoms with a canal raphe system showed that the genus Rhopalodia is not a monophyletic group (Ruck et al. 2016). In order for the classification to reflect evolutionary relationships, the least disruptive way to achieve the monophyly of taxa in this lineage was to subsume Rhopalodia into Epithemia. - M. Potapova

Cite This Page

Kociolek, P. (2011). Epithemia musculus. In Diatoms of North America. Retrieved June 20, 2024, from https://diatoms.org/species/epithemia_musculus


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