• Category
  • Length Range
    30-45.7 µm
  • Width Range
    5.8-6.2 µm
  • Striae in 10 µm



Valves are narrow, linear and lightly silicified. The valve margin is slightly irregular to undulate. The apices are rostrate to slightly subcapitate. The central nodule is slightly pinched together. Longitudinal ribs are narrow and slightly curved. The porte-crayon is relatively small and difficult to discern in LM. Both apical and transapical striae are parallel, but can be difficult to resolve in LM because they number roughly 40 in 10 μm. Under SEM, internally, the longitudinal ribs are narrow and irregular in thickness. The internal expression of the areolae are round to nearly rectangular. The apical striae become slightly offset from one another, particularly around the central area. A hyaline area is distal to the porto-crayon.


Frustulia pseudomagaliesmontana has only been confirmed from North America. This taxon has been reported from the eastern United States. Images on this page are from surface sediments from lakes in New York, Connecticut and New Jersey. Frustulia pseudomagaliesmontana grows in both lentic and lotic environments and can at times reach moderately high abundance.

Original Description

Frustulia pseudomagaliesmontana Camburn & Charles, sp. nov. (Pl. 18, figs. 12-16; Pl. 37, figs. 2, 3, SEM)

Valve narrow elliptic, margins may be slightly undulate; ends rostrate to subcapitate. Axial area narrow. Striae parallel to gently convergent at the ends. Striae, 37-40 in μm. Length, 41-44 μm. Breadth, 6-6.5 μm.

HOLOTYPE A.-G.C. 57556. In general diatom collection, Academy of Natural Sciences of Philadelphia.

Type locality. U.S.A., New York, Herkimer County, Fourth Lake (Bisby Lakes), 43°34’15’’ N, 74°58’15’’ W, Core 1, 0-1 cm, September 10, 1987.

Frustulia pseudomagaliesmontana is distinguished from F. magaliesmontana Choln. (Cholnoky 1957: 349, fig. 42) by its shorter length (41-44 μm compared to 55-70 μm for Cholnoky’s taxon).

  • Author
    Camburn and D.Charles 2000
  • Length Range
    41-44 µm
  • Width
    6-6.5 µm
  • Striae in 10µm

Original Images

Frustulia Pseudomagaliesmontana Orig Illus
Frustulia Pseudomagaliesmontana Orig Desc

Citations & Links


  • Index Nominum Algarum
  • North American Diatom Ecological Database
    NADED ID: 35007
  • The Academy of Natural Sciences, Drexel University

Cite This Page

Polaskey, M. (2018). Frustulia pseudomagaliesmontana. In Diatoms of North America. Retrieved June 23, 2024, from https://diatoms.org/species/frustulia-pseudomagaliesmontana


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