• Category
  • Length Range
    32-70 µm
  • Width Range
    12-21 µm
  • Striae in 10 µm



Valves are lanceolate, with bluntly apiculate apices. Longitudinal lines, formed by canals, are present along each valve margin. The longitudinal canals terminate prior reaching the apices. The axial area is narrow and linear. The central area is variable in development, from small and oval in the smallest specimens to transversely elliptic or nearly quadrangular in larger specimens. The proximal raphe ends vary from obliquely to distinctly hooked. Striae are slightly radial, becoming parallel to convergent at the apices. Areola density is 11-14 in 10 µm.

Some features are only visible under critical LM, or under SEM. For example, as in other Neidium taxa, the distal raphe ends are bifurcate and possess an apical flap (Hamilton et al. 1996). Features of the taxon include external “depressions” of the valve associated with the areolae and a network of "braided" silica on the interior of the valve. The only other taxon that has this internal complex network of braiding silica is N. boyeri Reimer. The internal proximal raphe ends terminate in a narrow linear-undulate central nodule, termed a rectelevectum (Van de Vijver et al. 2010). Externally, the raphe terminates in an elliptic, slightly raised helictoglossa.


This taxon has been recorded worldwide from the high arctic region between 40-80°N latitude (Hamilton et al. 1996, Pinseel et al. 2016). North American records indicate this species prefers cold alkaline waters of high mineral content (Hamilton et al. 1996; Bouchard et al. 2004), as well as Great Lakes (Lake Superior, Lake Huron) records indicating its preference for epipelic habitats in deep cold waters (Stoermer et al. 1980). Confirmed records include Ellesmere Island, Canada (Hamilton et al. 1996), cold high elevation lakes (~2000 m) in Northern Rock Mountains (per. comm. Bahls, 2021), and has been recorded in the deep waters of West Lake Okoboji and one location collection from Des Moines River, Iowa (Stoermer, 1964).

Original Description

Zellen von sehr robustem Habitus. Schalen elliptisch-lanzettlich mit schwach vorgezogenen, breit abgerundeten Polen. Raphe gerade, Zentralporen in der für die Gattung charakteristischen Weise komma- artig nach verschiedenen Seiten abgebogen. Axialarea eng, aber deutlich, in der Mitte etwas erweitert zu einer kleinen, querrundlichen Zentralarea. Streifen kräftig, 11-12 in 10 µ, radial, aber auf beiden Seiten mit verschiedenem Neigungswinkel zur Raphe (schief), die mittleren Streifen auf der einen Seite nur sehr schwach angedeutet, so dal die Zentralarea scheinbar einseitig den Schalenrand erreicht Streifen kräftig punktiert, Punkte sehr wenig enger stehend als die Streifen. Nahe dem Schalenrand jederseits eine deutliche Längslinie. Lange: 44 µ. Breite: 16 µ.

  • Author
    Hust. 1922
  • Length Range
    44 µm
  • Width
    16 µm
  • Striae in 10µm

Original Images

Ndistinctepunctatum  Orig Ill
Ndistinctepunctatum  Orig Descr

Citations & Links



Cite This Page

Bahls, L., Furey, P., Malik, H., Hu, K. (2021). Neidium distinctepunctatum. In Diatoms of North America. Retrieved June 23, 2024, from https://diatoms.org/species/neidium_distinctepunctatum


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