Diatoms of North AmericaDiatoms of North America

Sellaphora saugerresii

(Desm.) Wetzel and Mann 2015

Sellaphora Saugerresii Guide
  • Category
    Symmetric Biraphid
  • Length Range
    6.8-12.3 µm
  • Width Range
    3.1-3.5 µm
  • Striae in 10 µm
    20-22
  • Reported As
    Navicula minima (Grunow in Van Heurck 1880, pl. 14, fig. 15)
    Navicula seminulum (Grunow sensu Krammer and Lange Bertalot 1986, p. 230, pl. 76, figs 30-36)
    Sellaphora seminulum ((Grunow) Mann sensu Hofmann et al. 2011, p. 537, pl. 42, figs 22-26)

Identification

Sellaphora saugerresii LM6 Sellaphora saugerresii LM4 Sellaphora saugerresii LM7 Sellaphora saugerresii LM1 Sellaphora saugerresii LM3 Sellaphora saugerresii LM2
View image metadata
Wp030 02 Sem Sclbr

Description

Valves are linear-elliptic to linear-lanceolate with rounded ends. The axial area is narrow and straight. The central area is wide, more or less symmetric, and bow-tie shaped with two or three shorter, uneven striae. Striae are slightly radiate near the central area, becoming very parallel toward the poles. Striae may be resolved under optimal lighting in LM. In SEM, striae are seen to be biseriate and become uniseriate toward the axial area. Areolae are not resolvable under LM, but under SEM are small and round. The raphe is straight with slightly curved, tear-drop-shaped proximal ends. Terminal raphe fissures are curved toward the same side of the valve. Polar bars are absent.

There has been much confusion regarding the taxonomic identity of Sellaphora saugerresii and related species. The recent treatment of the former Eolimna minima and Sellaphora seminulum species complexes are further explained in Wetzel et al. (2015), and the specimens examined here appear to agree with the treatment of S. saugerresii described by the authors. Note that, some years back Sellaphora saugerresii was described as a 'doubtful synonym' of Navicula seminulum by Krammer and Lange-Bertalot (1986, p. 230), but we consider that the Lange-Bertalot images do, indeed, show S. saugerresii.

Autecology

There has been much confusion regarding the taxonomic identity of Sellaphora saugerresii and related species. The recent treatment of the former Eolimna minima and Sellaphora seminulum species complexes are further explained in Wetzel et al. (2015), and the specimens examined here appear to agree with the treatment of S. saugerresii described by the authors. Because small-celled naviculoid taxa are often dominant in benthic freshwater communities, they are considered ecologically important taxa and in need of revision and further scrutiny. The recent treatment by Wetzel et al. (2015) will aid in clarifying the habitat preferences and distribution of S. saugerresii and related taxa.

Original Description

N. minutissima, laevis, lanceolato-elliptica, apicibus parum acutis vel obtusis. Long. 0.013 mm; lat. 0.005 mm. Altero latere oblonga truncata. Viva in aqua antilae inclusa in lagena.

  • Basionym
    Navicula saugerrei
  • Author
    Desm. 1858
  • Length Range
    13 µm
  • Width
    5 µm

Original Images

Sellaphora Saugerresii Origdesc

Cite This Page

Frohn, A. (2016). Sellaphora saugerresii. In Diatoms of North America. Retrieved November 21, 2024, from https://diatoms.org/species/sellaphora_saugerresii

Responses

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