• Category
  • Length Range
    7-18 µm
  • Width Range
    5-9 µm
  • Striae in 10 µm
    Raphe valve 24-32, rapheless valve 11-14



Valves are elliptic. The raphe valve has a narrow axial area and small, circular central area. The raphe is straight and filiform. Striae are 24-32 in 10 µm, radiate and interrupted by a hyaline smooth submarginal ring. The areolae are distinguished under LM, 25-32 in 10 µm.

The rapheless valve has a relatively wide lanceolate axial area. Striae are slightly radiate in the center of the valve, becoming radiate toward the ends. Each stria is composed of two to five (typically three) large, transversely rectangular areolae. Often, the central striae are separated by wider virga on one side of the valve. Externally, small punctae, which do not penetrate the valve are observed between areolae in the axial area (SEM).


Cocconeis neodiminuta has been recorded in streams and rivers of northern California.

Original Description

Valvi parvulis, late-ellipticis, 8-18 µm longis, 6-9 µm latis. RLV striis valide punctatis, 12-15/10 µm, area valvae angusta vel angusto-lanceolata; RV striis tenuis, 24-32/µm, puncta 25-32/10 µm, area valvae angusta, raphe tenuisima.

  • Author
    Krammer 1990
  • Length Range
    8-18 µm
  • Width
    6-9 µm
  • Striae in 10µm

Original Images

Cocconeis neodiminuta orig desc

Cite This Page

Bishop, I. (2021). Cocconeis neodiminuta. In Diatoms of North America. Retrieved May 29, 2024, from https://diatoms.org/species/cocconeis-neodiminuta


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