Navicula longicephala
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Category
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Length Range17-22 µm
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Width Range3.1-4.0 µm
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Striae in 10 µm18-21
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Reported AsNavicula bicephala (Patrick and Reimer 1966)
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ContributorMarina Potapova - Mar 2011
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ReviewerSarah Spaulding - Dec 2011
Identification
Description
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.
Autecology
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Size Range, µm3
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Motility
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Attachment
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Habitat
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Colony
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Occurrence
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BCG
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Waterbody
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Distribution
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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.
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AuthorHust. 1944
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Length Range19-22 µm
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Width3-4 µm
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Striae in 10µm18-20
Original Images
Citations & Links
Cite This Page
Potapova, M. (2011). Navicula longicephala. In Diatoms of North America. Retrieved December 26, 2024, from https://diatoms.org/species/45965/navicula_longicephala
Responses
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.
Navicula longicephala
- Valves linear
- Valves 3.1-4.0 μm wide
- Valve apices rostrate to capitate
- Central striae strongly radiate
- Striae 18-21 in 10 μm
Valves are linear with rostrate to capitate apices. 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.