Diatoms of North AmericaDiatoms of North America

Frustulia soror

Graeff and Kociolek 2011

Frustulia Soror Guide
  • Category
    Symmetric Biraphid
  • Length Range
    28.5-52.0 µm
  • Width Range
    7.5-9.5 µm
  • Striae in 10 µm
    34-36 at the center, 35-37 at the ends
  • Reported As
    Frustulia weinholdii (Patrick and Reimer 1966)

Identification

Frustulia soror LM6 Frustulia soror LM5 Frustulia soror LM4 Frustulia soror LM3 Frustulia soror LM2 Frustulia soror LM1
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Frustulia soror SEM2

Description

Valves are linear-lanceolate with slightly rostrate rounded apices. The striae are parallel or slightly radiate at the valve center, parallel along the length of the valve and convergent at the ends. Areolae comprising the striae are round or oval. An isolated, or elongated, poroid is sometimes present at the central area. The central area is relatively linear in shape. Elongated areolae may be present in a transverse depression (SEM feature) found at the external raphe ends. Internally, the areolae are occluded. The raphe branches are curved slightly. Internally, the longitudinal ribs terminate before reaching the helictoglossae. Internally, at the central area a longitudinal rib is incomplete on one side of the raphe and completed on the other.

F. soror is a species that has been separated from the broad taxon concept of F. weinholdii established by Patrick and Reimer (1966) where they described the apices of F. weinholdii as round to capitate. At least two additional species have since been separated from F. weinholdii, including those populations with capitate apices. Under the broad concept of the taxon, reports of F. weinholdii have been numerous in the United States.

Autecology

Original Description

Valves linear-lanceolate with slightly rostrate rounded apices. The striae are parallel or slightly radiate at the valve center, parallel along the length of the valve, and convergent at the ends of the valve. Areolae comprising the striae are round or oval. An isolated or elongated poroid is sometimes present at the relatively linear central are. Elongated areolae can be present in the transverse depression found at the external raphe ends. Internally, the areolae are occluded.The raphe branches are curved slightly. Internally, the longitudinal ribs terminate before reaching the helictoglossae. At the internal central area, the dorsal longitudinal rib is incomplete and the ventral rib is complete. Details of the cingulum are unknown.

  • Author
    Graeff and Kociolek 2011
  • Length Range
    28.5-52.0 µm
  • Width
    7.5-9.5 µm
  • Striae in 10µm
    34-36 at the center, 35-37 at the ends

Cite This Page

Graeff, C. (2011). Frustulia soror. In Diatoms of North America. Retrieved April 27, 2024, from https://diatoms.org/species/frustulia_soror

Responses

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