• Category
  • Length Range
    31-49 µm
  • Width Range
    15-16 µm
  • Striae in 10 µm
  • Reported As
    Diploneis ovalis (Krammer and Lange-Bertalot 1986, p. 286, fig. 108: 14-16)



Valves are elliptic with rounded apices. The longitudinal canals are narrow. The axial area is occupied almost completely by a broad raphe. The central area is round to oval, 3.8-4.5 µm wide. Striae are composed of one row of coarse, round areolae, 15 in 10 μm.

This taxon should be closed compared with other, similar species. For example, D. krammeri has been called the "false Diploneis ovalis" because it is commonly misinterpreted (Lange-Bertalot and Reichardt 2000).


Diploneis krammeri has been collected from a few small headwater fens, ponds and streams in the mountains of western Montana (Montana Diatom Database). In this region, it prefers cold, somewhat alkaline, oligotrophic waters with low to moderate conductivity.

Atlantic  Pond  Gnp 1
Credit: Loren Bahls
Atlantic Pond, Glacier National Park, Montana: home of Gomphonema americobtusatum.

Original Description

Valvae ellipticae vel lineari-ellipticae (numquam late rhombico-ellipticae) apicibus late rotundatis. Longitudo (10) 20-65 µm, latitudo (7) 10- circiter 25 µm. Raphe leviter arcuata fissuris internis externisque aliquid sed non multum lateralibus sitis inter se, extremis centralibus distincte et fere longe dilatatis fissurisque terminalibus curte deflexis unilateraliter. Area axialis (alias depressiones collaterales raphis) modice angusta. Area centralis (alias nodulus centralis) modice ampla, elliptica "appendices ad instar litterae H" nullae vel inconspicuae apparentes. Diametrus area/noduli centralis 4-6 µm (nec 6-10 µm ut in Diploneis ovalis). Striae transapicales modice radiantes in media valvae ad apices versus magis sed non valde radiantes, 10-14 in 10 µm. Puncta striarum simplicia numquam duplicta nec in quincuncem sita, 10-15 in 10 µm. Quoad aspectum submicroscopicum structurae typicae se praestant significanter imaginibus ultramicrophotogr. (REM), vide tab. 5 et 6 et comarate tab. 1 et 2 speciei Diploneis ovalis.

  • Author
    Lange-Bert. and E.Reichardt in Rumrich et al. 2000
  • Length Range
    (10) 20-65 µm
  • Width
    (7) 10-25 µm
  • Striae in 10µm

Original Images

Diploneis krammeri orig desc 2
Diploneis krammeri orig desc 1
Diploneis krammeri orig desc 4
Diploneis Krammeri Origdesc001

Citations & Links




Jul 05, 2019 - Change in species concept

From October 2014 to July 2019, the images on this page included what is now recognized as two distinct species: Diploneis krammeri and a species that is now being described. The larger specimens of the new taxon were removed, leaving a more narrow concept of D. krammeri.

The posted dimensions were changed from L: 22-62; W: 12.5-23.0; S: 11-14 to L: 31-49; W: 15-16; S: 11-12.

The new taxon will be included upon publication in 2019. The archived page for Diploneis krammeri is available upon request. - S. Spaulding

Cite This Page

Bahls, L. (2014). Diploneis krammeri. In Diatoms of North America. Retrieved September 25, 2021, from https://diatoms.org/species/diploneis_krammeri


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