Diatoms of North AmericaDiatoms of North America

Sellaphora rexii

Potapova and Ponader 2008

Sellaphora Rexii Guide
  • Category
    Symmetric Biraphid
  • Length Range
    22-33 µm
  • Width Range
    7.1-8.6 µm
  • Striae in 10 µm
    20-24

Identification

Gs003341 Rexii S12 Holo2B Real Gsn95461 S8 Gs003341 Rexii Holo3B Gs003341 Rexii S7C Gs003341 Rexii S5B
View image metadata
Sellaphora rexii SEM1

Description

Valves are elliptic with subrostrate apices. The axial area is linear, formed by grooves, one at each side of the raphe. Grooves are approximately 0.5 μm wide and covered externally by non-porous conopeum. Grooves and conopea are interrupted by the central area, which is transversely rectangular, or bow-tie-shaped and bordered by striae of an irregular length. The striae are uniseriate, radiate throughout most of the valve, but parallel or convergent near the apices. Near the valve ends, the striae are interrupted and internally form "polar bars", which are visible in LM. The areolae are small, rounded, approximately 50-55 in 10 μm. The raphe is straight, with expanded central endings.

Autecology

Original Description

Valves are elliptical, with subrostrate apices. 22-33 μm long, 7.1-8.6 μm wide (Fig. 4). The axial area is straight, formed by grooves, one at each side of the raphe. Grooves are approximately 0.5 μm wide and covered externally by non-porous conopeum (Fig. 4E). Grooves and conopea are interrupted by the central area, which is transversely rectangular, or bow-tie-shaped and bordered by striae of an irregular length. The striae are uniseriate, radiate throughout most of the valve, but parallel or convergent near the apices, 20-24 in 10 μm. Near the valve ends, the striae are interrupted and internally form "polar bars" which are visible on LM photographs (Fig. 4A-D). The areolae are small, rounded, approximately 50-55 in 10 μm. The raphe is straight, with expanded central endings, and terminal fissures curved to the secondary side of the valve.

  • Author
    Potapova and Ponader 2008
  • Length Range
    22-33 µm
  • Width
    7.1-8.6 µm
  • Striae in 10µm
    20-24

Original Images

Se Rexii Orig Ill
Serexii Orig Descr

Cite This Page

Potapova, M. (2010). Sellaphora rexii. In Diatoms of North America. Retrieved April 25, 2024, from https://diatoms.org/species/sellaphora_rexii

Responses

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