• Category
  • Length Range
    17.5–37.5 µm
  • Width Range
    10-11.5 µm
  • Striae in 10 µm



Valves are linear-elliptic, with bluntly rounded ends. Valves at the smaller end of the size range are roundly- elliptic in shape. The axial area is narrow and linear. Near the central area, the axial area is slightly expanded to a small, barely distinguishable central area, 1.5–2.7 µm wide. The longitudinal canal is narrow and linear throughout its length. The longitudinal canal is slightly expanded at the middle of the valve. Areolae within the canal are hardly visible under LM. The raphe is straight, with slightly expanded proximal ends and shortly curved distal ends. The striae are parallel in the middle of the valve, becoming radiate toward the valve apices. The areolae are small, round and number 30 in 10 μm.

The type material of D. boldtiana was examined (Idei and Kobayasi 1989), and SEM observations were made of the type. The SEM images (Figs 11, 13) show 1-2 rows of areolae in the middle of the valve, becoming triseriate toward the valve apices.


In North America, this species was documented in moderate abundance from lake sediments of the northeast US. It was found in Maine (Lake Gilman, Crosby Pond, Little Lake) and in Massachusetts (Lower Spectacle Pond)(EPA Northeast Lakes Regional Survey 2017).

Original Description

Valve oblong-elliptic, 0,03 m. m. in length and 0,012 m .m. in breadth. Costae 14 in 0,01 m. m. Puncta fine and indistinct. Central nodule quadrate, small. Furrows closely accompanying the prolongations of the central nodule, almost straight, except on the middle, where they are bent.

Pl. II, fig. 12.

This species, of which I have seen only some few specimens occurs at Viando (Sb. 4.). It comes probably very near to Cocconeis baltica Schum. (II, I, 13) but this form differs, according to the figure, published by Schumann, in the end-nodules, which are at a considerable distance from the ends.

  • Author
    Cleve 1891
  • Length Range
    30 µm
  • Width
    12 µm
  • Striae in 10µm

Original Images

Diploneis boldtiana orig illus
Diploneis Boldtiana Orig Desc

Cite This Page

Jovanovska, E., Phillips, N., Polaskey, M. (2019). Diploneis boldtiana. In Diatoms of North America. Retrieved April 16, 2024, from https://diatoms.org/species/diploneis-boldtiana


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