• Category
  • Length Range
    7.0-17.5 µm
  • Width Range
    3.6-5.4 µm
  • Striae in 10 µm
  • Synonyms
    Planothidium conspicuum (Mayer) Aboal in Aboal, Alvarez-Cobelas, Cambra and Ector
  • Reported As
    Achnanthes pinnata (Patrick and Reimer 1966)



Valves are linear-elliptic. The raphe valve has a narrow axial area and transversely rectangular central area that reaches both valve margins. The rapheless valve has a lanceolate axial area and no distinct central area, though the two middle striae may be slightly more distant from each other than less central striae. The raphe is straight, with slightly expanded terminal and central ends, without terminal fissures. Internally (SEM), the central raphe ends curve toward opposite sides. Striae are almost parallel in the valve center, but become strongly radiate approaching the poles of both valves, biseriate, 12-16 in 10 µm. A single row of areolae exists on the valve mantle, with each areola opposed to a biseriate stria. The external and internal openings of the areolae are circular or somewhat angular, isodiametric.

Original Description

A. valvis prorsus ovalibus finibus rotundatis, 0,01—0,012 mm longis, 0,0055 mm latis; striis paene parallelis, ad fines subradiantibus, duobus mediis utriusque valvae perspicue distinctis, ab interiore parte ad exteriorem subappropin-quantibus, interdum una stria tenuissima in valva inferiore inter strias medias magis distantes intercalata, striis validis, 13—14 intra 0,01 mm

  • Basionym
    Achnanthes conspicua
  • Author
    A.Mayer 1919
  • Length Range
    10-12 µm
  • Width
    5.5 µm
  • Striae in 10µm

Original Images

Orig Ill  Plconsp
Orig Descr  Plconsp

Cite This Page

Potapova, M. (2010). Platessa conspicua. In Diatoms of North America. Retrieved June 13, 2024, from https://diatoms.org/species/platessa_conspicua


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