Diatoms of North AmericaDiatoms of North America

Navicula subrhynchocephala

Hust. 1935

Navicula Subrhynchocephala Guide
  • Category
    Symmetric Biraphid
  • Length Range
    29-42 µm
  • Width Range
    7.5-8.9 µm
  • Striae in 10 µm
    12-14

Identification

Navicula subrhrynchocephala LM6 Navicula subrhrynchocephala LM7 Navicula subrhyncocephala LM4 Navicula subrhynchocephala LM2 Navicula subrhynchocephala LM1 Navicula subhynchocephala LM3 Navicula subrhrynchocephala LM5
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Navicula subrhynchocephala SEM2 Navicula subrhynchocephala SEM1 Navicula subrhynchocephala SEM6 Navicula subrhynchocephala SEM4

Description

Valves are linear-lanceolate with variable apices, from subrostrate to capitate. The axial area is narrow and straight. The central area is rounded and slightly asymmetrical. The raphe is straight, with dilated external proximal raphe ends that are hooked towards the secondary side of the valve. The terminal raphe fissures are hooked to the secondary valve side. Striae are radiate, becoming parallel then convergent at the apices. The striae near the center are straight or very slightly bent. The areolae are clearly visible under LM, and number appoximately 24-25 in 10 μm.

Autecology

Original Description

Navicula subrhynchocephala nov. spec. Schalen lanzettlich mit vorgezogenen, schwach kopfig gerundeten Enden, 35-45 μ lang, 6-8 μ, breit. Raphe gerade, Endspalten nach gleichen Seiten abgebogen. Axialarea sehr eng, linear, Zentralarea quer elliptisch, ziemlich groß. Transapikalstreifen im mittleren Teil der Schale wenig radial, an den Enden konvergent, 13-16 in 10 μ, zart liniert (Taf. I, Fig. 11) .

  • Author
    Hust. 1935
  • Length Range
    35-45 µm
  • Width
    6-8 µm
  • Striae in 10µm
    13-16

Original Images

Navicula Subrhynchocephala Ill
Navicula Subrhynchocephala Descr

Cite This Page

Potapova, M. (2011). Navicula subrhynchocephala. In Diatoms of North America. Retrieved November 23, 2024, from https://diatoms.org/species/navicula_subrhynchocephala

Responses

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