• Category
  • Length Range
    14-29 µm
  • Width Range
    3.4-5.1 µm
  • Striae in 10 µm



Valves are linear to linear-lanceolate with slightly drawn-out ends. The raphe is absent on one valve. The rapheless valve has a narrowly rhomboid axial area, which sometimes widens in the middle portion of the valve to form an asymmetrical central area. The raphe valve has a narrowly lanceolate axial area and circular or elliptical, sometimes asymmetrically expanded central area. The raphe has a slightly curved external and straight internal slit. The axial and central areas often have siliceous thickenings and depressions. The proximal raphe ends are slightly expanded externally. Internally, the proximal raphe ends are bifurcated and turned sharply backwards. Striae are radiate through both valves, 20-24 in 10 μm. The external openings of the areolae are covered by the kidney-shaped hymens.


Original Description

Schalen linear mit wenig konvexen Seiten und schwach vorgezogenen, stumpf gerundeten Enden, um 20 μ lang, etwa 4 μ breit. Raphenschale mit gerader, fadeförmiger Raphe, mit voneinander entfernt gestellten Zentralporen; Axialarea sehr eng, Zentralarea ziemlich groß, annähernd kreisförmig; Transapikalstreifen ziemlich kräftig, durchweg – besonders vor den Polen – radial, in der Mitte etwa 20-24 in 10 μ, gegen die Enden wenig oder gar nicht enger werdend. Raphenlose Schale mit schmal lanzettlicher Pseudoraphe, Transapikalenstreifen etwa 24 in 10 μ, durchschnittlich etwas dichter gestellt als auf der Raphenschale und etwas weniger stark radial.

  • Basionym
    Achnanthes subrostrata
  • Author
    Hust. 1942
  • Length Range
    20 µm
  • Width
    4 µm
  • Striae in 10µm

Original Images

Orig Ill  Ac Subrostr 1
Orig Descr  Ac Subrostr

Cite This Page

Potapova, M. (2010). Nupela subrostrata. In Diatoms of North America. Retrieved August 15, 2018, from https://diatoms.org/species/nupela_subrostrata


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