• Category
  • Length Range
    22-62 µm
  • Width Range
    12.5-23.0 µm
  • Striae in 10 µm
  • Reported As
    Diploneis ovalis (Krammer and Lange-Bertalot 1986, p. 286, fig. 108: 14-16)



Valves are elliptic to linear-elliptic with broadly rounded apices. The longitudinal canals are narrow, the width of one to three areolae, and follow along the margins of the axial and central areas. The axial area is occupied almost completely by a broad raphe sternum that encloses the raphe. The central area is large and orbicular, 3.8-7.2 µm wide. Striae are uniseriate and radiate throughout. Areolae are large, blocky and number 15-20 in 10 µm.

Lange-Bertalot and Reichardt (2000) refer to D. krammeri as the "false Diploneis ovalis" because it has been misinterpreted by many, including this contributor, as the latter species. The original posting of "D. ovalis" to this website (28.10.2012) was in fact D. krammeri. I thank Elena Jovanovska for bringing this error to my attention.


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

Cite This Page

Bahls, L. (2017). Diploneis krammeri. In Diatoms of North America. Retrieved July 21, 2018, 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.