• Category
  • Length Range
    32.5-58.7 µm
  • Width Range
    20.7-32.6 µm
  • Striae in 10 µm
  • Reported As
    Diploneis ovalis (Hustedt 1930, p. 249, fig. 390)



Valves are elliptic to oval with broad, round apices. The longitudinal canals are narrow, the width of one to three areolae, and follow the margin of the axial and central areas. The axial area is occupied almost completely by a broad raphe. The central area is large and orbicular, 4.9-8.5 µm wide. Striae are uniseriate and radiate throughout. Areolae are large, blocky and number 16-20 in 10 µm.

Diploneis ovalis is less common than D. krammeri, which is often misidentified as D. ovalis.


In the Northwest United States, D. ovalis is less common than D. krammeri, but the species are often confused. The specimens illustrated here are from Lake Caroline, a small lake in the Cascade Mountains of Washington.

In Europe, this taxon is reported to prefer low alkalinity, low conductance, weakly acid waters (Rumrich et al. 2000).

Lake Caroline3
Credit: Ryan Davis, Adventurers and Scientists for Conservation
Lake Caroline, Chelan County, Washington: home of Sellaphora alastos.

Original Description

Pinnularia ovalis Hilse nov. spec. Diese Species gelicht auf den eraten Blick sehr der Navicula elliptica, welche in den Rabenh. Dec. unter Nr. 786 geliefert worden ist, und der Navicula ovalis W. Smith. Doch sie ist entschieden eina Pinnularia, denn ihre Qerleisten lassen sich nicht in einselne Punkte auflosen, euch kommen nicht, wie bei W. Smith, 27 auf 0,0001", sondern 38 auf 0,001", stehen also viel enger beisammen und sind bedeutedn sarter, so dans man sie nur bei scharfer Vergrosserund zu erkennen wemag. Die Lange der P. ovalis betragt meist bis ___. Die Form ist elliptische; es kommen breite und schmale Exemplare vgr. Gesammlt in Ziegengrunde bei Strehlen in Mai 1860. Rabenh. Dec. 103 und 104 Nr. 10005.

  • Basionym
    Pinnularia ovalis
  • Author
    Hilse in Rabenh. 1861

Original Images

Pinnularia Ovalis Text 268X0
Pinnularia Ovalis  Descr 268X0


May 06, 2022 - Replacement of images

From 23 December 2013 until 8 March 2021, this page included images for an undescribed taxon similar to Diploneis krammeri. We consider that the images included now are in alignment with D. ovalis. - L. Bahls

Cite This Page

Bahls, L. (2014). Diploneis ovalis. In Diatoms of North America. Retrieved April 21, 2024, from https://diatoms.org/species/diploneis_ovalis1


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