• Category
  • Length Range
    10.0-21.5 µm
  • Width Range
    5.3-6.8 µm
  • Striae in 10 µm



Valves are linear-elliptic with rounded apices to elliptic. The axial area is linear to lanceolate. The axial area expands near the middle of the valve to form a round to transapically elongate central area, 1.3–2.5 µm wide. The longitudinal canal is linear to lanceolate. The longitudinal canal is composed of a single row of round areolae throughout its length. The raphe is straight, with slightly expanded proximal ends. The distal raphe has weakly deflected distal fissures. The striae are radiate. Striae are uniseriate, becoming biseriate near the valve margin. The striae are composed of small, round areolae, numbering 30 in 10 μm.


This taxon is rare in occurrence, but has been documented in the images on this page from the northeast (Deep Lake, Connecticut) (EPA lakes survey 2017). It was also found in streams of the northwest (Fanno Creek, Oregon; Harris Creek, Washington; Longfellow Creek Seattle, Washington) in the USGS Pacific Northwest Regional Survey (2016).

Original Description

Diploneis fontanella Lange-Bertalot nov. spec.

Diploneis ovalis var. oblongella (Nägeli) Cleve sensu auct. nonnull. partim.
Diploneis puella (Schumann) Cleve sensu auct. nonnull. partim.

Diagnosis differens versus Diploneis separanda et Diploneis fontium (vide infra)

Valvae ellipticae quoad specimina minora sed plerumque lineari-ellipticae apicibus late rotundatis. Longitudo 16-30 µm, latitudo 7-8.5 µm nee 8-13 µm latitudo ita distincte differt a Diploneis fontium nov. spec. Raphe paulo vel modice lateralis (nee filiformis) apparens. Area axialis modice angusta. Area centralis numquam parva sed distincte dilatata et circularis vel apicaliter elliptica ad instar. Diametrus areae centralis transapicaliter circiter 2.5-3 µm (ita distincte differt a Diploneis separanda nov. spec.). Canales laterales ad sternum nee angusti nee lati sed distincte convexi formati circum aream centralem. ,,Appendices ad instar litterae H" nullae vel inconspicue apparentes. Striae transapicales fortius radiantes usque ad apices, 16-18 in IO µm (id est minus quam D. separanda, aeqaliter cum D. fontium). Puncta striarum, circiter 22-25 in 10 µm, bene aspectabilia microscopio photonico id est minus quam 30-35 in specieD. separanda sed plus quam circiter 16 in D. fontium.

Aspectus ultramicroscopicus externus vide Figs 74: 14, 15; 75: 4. Generaliter aspectus similis ut in specie D. separanda (vide tabulae 76, 77) quia foramina cribroidea prope sternum uniseriata tum divisa et quomodo biseriata sed dense ordinata inter se. Ita a specie D. fontium cum foraminibus constanter uniseriatis satis differt. Raphe cum extremis centralibus distalibusque curte hamatis vix differt ab alteris speciebus generis.

  • Author
    Lange-Bert. in Werum and Lange-Bert. 2004
  • Length Range
    16–30 µm
  • Width
    7.0-8.5 µm
  • Striae in 10µm

Original Images

Diploneis Fontanella Orig Illus
Diploneis Fontanella Orig Desc2

Cite This Page

Jovanovska, E., Phillips, N., Tyree, M. (2019). Diploneis fontanella. In Diatoms of North America. Retrieved September 19, 2019, from https://diatoms.org/species/diploneis-fontanella


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