• Category
  • Length Range
    17-22 µm
  • Width Range
    3.1-4.0 µm
  • Striae in 10 µm
  • Reported As
    Navicula bicephala (Patrick and Reimer 1966)



Valves are linear with rostrate to capitate apices. The axial area is narrow and straight. The central area is small. The raphe is straight, with close proximal ends. Striae are strongly radiate around the center, becoming convergent at the apices. The areolae are indistinguishable under LM, approximately 50 in 10 μm.


Original Description

Navicula longicephala nov. spec. Schalen schmal linear mit parallelen Seiten und schmalen, kopfig abgeschnürten und ziemlich lang geschnäbelten Enden, 19-22 µ lang, 3-4 µ breit. Raphe gerade, fadenförmig, Polspalten undeutlich, sehr klein. Axialarea sehr schmal linear, um den Zentralknoten etwas quer erweitert und eine kleine Zentralarea bildend. Transapikalrippen 18-20 in 10 µ, im mittleren Teil radial, an den Enden senkrecht zur Mittellinie, Längslinien sehr zart und kaum erkennbar. Fig. 17.

  • Author
    Hust. 1944
  • Length Range
    19-22 µm
  • Width
    3-4 µm
  • Striae in 10µm

Original Images

Navicula Longicephala  Ill
Navicula Longicephala  Descr

Citations & Links


  • Index Nominum Algarum
  • North American Diatom Ecological Database
    NADED ID: 46507
  • Hustedt Collection

Cite This Page

Potapova, M. (2011). Navicula longicephala. In Diatoms of North America. Retrieved June 21, 2024, from https://diatoms.org/species/navicula_longicephala


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