Navicula subrhynchocephala | Species - Diatoms of North America

Category

Symmetric Biraphid
Length Range

29-42 µm
Width Range

7.5-8.9 µm
Striae in 10 µm

12-14

Contributor

Marina Potapova - Mar 2011
Reviewer

Mark Edlund, Rex Lowe - Oct 2011

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Identification

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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

Size Range, µm3

101-1000
Motility

Moderately motile
Attachment

Unattached
Habitat

Benthic
Colony

Solitary
Occurrence

Rare
BCG

BCG 3
Waterbody

Inland Rivers
Distribution

Western rivers 2004 California coastal rivers 2017
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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

Citations & Links

Citations

Cite This Page

Potapova, M. (2011). Navicula subrhynchocephala. In Diatoms of North America. Retrieved December 26, 2024, from https://diatoms.org/species/45912/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.