• Category
  • Length Range
    39-48 µm
  • Width Range
    9.4-11.4 µm
  • Striae in 10 µm



Valves are linear-elliptic with broadly rostrate to subcapitate apices. A longitudinal line runs along each side of the valve close to the mantle. The axial area is narrow, barely wider than the raphe. The central area is circular and about one-half the width of the valve at center. The raphe is filiform with simple proximal ends that are deflected to the same side. Striae are strongly radiate in the middle, becoming parallel then weakly convergent near the apices. Areolae in the striae are somewhat elongate and distinct in LM, and number 20-24 in 10 µm.


Neidiopsis wulffii is uncommon in oligotrophic and very low-conductivity lakes and ponds of the Northern Rocky Mountains. In these habitats, pH ranges from 6.40 to 7.57 and specific conductance ranges from 7 to 16 µS/cm. Neidiopsis wulffii was recently reported from Arctic Canada in waters ranging from 18 to 134 µS/cm (Antoniades et al. 2008). Previously, this taxon was known only from the type locality in Greenland (Lange-Bertalot 2001).

Kootenai  Lake
Credit: Loren Bahls
Kootenai Lake on the Waterton River, Glacier National Park, Montana: home of Neidiopsis wulffii.

Original Description

Valve linear-lanceolate, rostrate-capitate, with very slightly triundulate margins. On each side a deep sulcus. L. 35 µ, b. 8,8 µ, striae 18 in 10 µ, radiate throughout, finely punctate. Fig. 1.

  • Basionym
    Navicula wulffii
  • Author
    J.B.Petersen 1924
  • Length Range
    35 µm
  • Width
    8.8 µm
  • Striae in 10µm

Original Images

N Wulffii  Original

Cite This Page

Bahls, L. (2012). Neidiopsis wulffii. In Diatoms of North America. Retrieved June 23, 2024, from https://diatoms.org/species/neidiopsis_wulffii


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