• Category
  • Length Range
    12-26 µm
  • Width Range
    3.7-4.5 µm
  • Striae in 10 µm
  • Reported As
    Achnanthes lineariformis (Lange-Bertalot 1993)
    Achnanthes linearioides (Lange-Bertalot in Lange-Bertalot and Moser 1994)
    Achnanthes linearis (Germain 1981)



Valves are linear or linear-elliptic with rounded ends. The raphe valve has a linear axial area that gradually widens into a small or almost indistinct central area. The raphe is straight, filiform, and lacks terminal fissures. Internally, the central raphe endings are curved to opposite sides. The rapheless valve has a narrow, linear axial area and no distinct central area. Striae are uniseriate and slightly radiate. Each stria in the middle part of the valve contains 5-6 areolae on valve face. The valve mantle bears one row of areolae.


Rossithidium anastasiae is a widely distributed diatom, often found in colder waters in Europe (Mölder & Tynni 1972, Krammer & Lange-Bertalot 2004) and in North America. Considering that most records of R. linearis are in fact R. anastasiae, data in the ANSP databases and catalogues show that this species is often found in low-conductivity lakes and sometimes streams of the northeastern USA, and, occasionally, in the Rocky Mountains. Hofmann et al. (2011) stated that this diatom is mostly found in oligo- to mesotrophic waters of low conductivity.

Original Description

  • Basionym
    Achnanthes anastasiae
  • Author
    Kaczmarska 1985
  • Length Range
    17-25 µm
  • Width
    4-5 µm
  • Striae in 10µm
    24–26 on the raphe valve, 22–25 on the rapheless valve

Original Images

Achnanthes anastasiae orig illus
Achnanthes anastasiae orig illus 2
Achnanthes anastasiae orig descr

Cite This Page

Potapova, M. (2011). Rossithidium anastasiae. In Diatoms of North America. Retrieved July 19, 2024, from https://diatoms.org/species/rossithidium_anastasiae


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