Rossithidium nodosum
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Category
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Length Range9.0-11.9 µm
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Width Range2.9-3.3 µm
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Striae in 10 µm16-20
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ContributorMarina Potapova - May 2009
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ReviewerSarah Spaulding - May 2010
Identification
Description
Valves are linear to linear-elliptic with rounded ends, which are slightly drawn-out. Striae on both valves are biseriate. Areolae are elliptic or angular and transapically elongated. Internally, areoale are covered by hymenes. Striae are slightly radiate throughout both valves. Striae number 16-20 in 10 µm. Valve mantle bears one row of elongated areolae; one areola is opposite to a stria, and one is between two striae.
The raphe valve has narrow axial area, which widens into a small central area. Externally, the distal raphe ends are curved toward the same side of the valve. The distal raphe ends are slightly expanded. The central raphe ends are slightly expanded. Internally, the central raphe ends curve to opposite sides.
The rapheless valve has narrowly linear axial area, which sometimes widens unilaterally into a small central area.
Autecology
reported from oligotrophic cold waters
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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
- Learn more about this
Original Description
Schalen linear mit etwas erweiterter Mitte und schwasch kopfformigen stumpfen Enden. Lange 15-26 µm, Breite 5-6 µm, Querstreifen 14-17 in 0.01 µm, stark und deutlich punktiert, an der Unterschale etwas radial, an der Oberschale parallel und bisweilen in der Mitte fehlend.
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BasionymAchnanthes nodosa
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AuthorA.Cleve 1900
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Length Range15-26 µm
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Width5–7 µm
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Striae in 10µm14-17
Original Images
Citations & Links
Citations
Updates
Dec 26, 2024 - Achnanthes nodosa transferred to Rossithidium nodosum
Achnanthes nodosa was transferred to Rossithidium nodosum by Aboal in 2003. The transfer is now reflected in the website. Sarah Spaulding
Cite This Page
Potapova, M. (2009). Rossithidium nodosum. In Diatoms of North America. Retrieved December 26, 2024, from https://diatoms.org/species/44351/rossithidium_nodosum
Responses
The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Rossithidium nodosum 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.
Rossithidium nodosum
- Striae slightly radiate
- Striae biseriate
- Small central area
- Linear-elliptic shape
Valves are linear-elliptical or elliptical with slightly drawn-out ends. The striae are slightly radiate throughout both valves and biseriate. The axial area is narrow. The central area is small, or absent. If present, it may be asymmetrical on the rapheless valve.