Diatoms of North AmericaDiatoms of North America

Cymbopleura laszlorum

Bahls and T.Luna 2018

Cymbopleura Laszlorum Guide
  • Category
    Asymmetric Biraphid
  • Length Range
    41-54 µm
  • Width Range
    9.7-11.4 µm
  • Striae in 10 µm
    14 at the valve center up to 22 at the apices

Identification

Cymbopleura Laszlorum Mdc 689501 1 Cymbopleura Laszlorum Mdc 689501 2 Cymbopleura Laszlorum Mdc 689301 3 Cymbopleura Laszlorum Mdc 689301 4 Cymbopleura Laszlorum Mdc 689301 5
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Description

Valves are elliptic-lanceolate with convex margins and rostrate to subrostrate apices. Valves are symmetric with respect to both the apical and transapical axes. The axial area widens gradually towards the central area. The central area is moderately large and variable in shape, most often transversely elliptic to rectangular, sometimes shaped like a bow tie. The raphe is lateral, narrowing toward the ends. Proximal raphe ends are deflected gently toward the ventral margin and terminate in slightly inflated pores. Terminal raphe fissures are hook-shaped and concave toward the dorsal margin. Striae are uniseriate and radiate throughout, 14 in 10 µm at the valve center, up to 22 in 10 µm at the apices. Areolae are also variable in density, 20 in 10 µm in striae at the valve center, up to 30 in 10 µm at the apices.

Autecology

Cymbopleura laszlorum is known only from a floodplain fen adjacent to the Madison River in southwest Montana. The collection sites for C. laszlorum are open water pools and rivulets that receive calcium-rich groundwater discharge (see photo below). Vegetation at the collection sites is composed almost exclusively of the Eleocharis quinqueflora (Hartmann) O. Schwarz community type. The fen and adjoining stream channels support large populations of three rare plant species: Primula incana M.E. Jones, Castilleja gracillima Rydberg and Castilleja minor (A. Gray) A. Gray v. exilis (A. Gray) J.M. Egger. At the type locality, Cymbopleura laszlorum was an uncommon element (<1 % abundance) of a benthic diatom association dominated by Mastogloia lacustris (Grunow) Grunow in Van Heurck, Cymbopleura florentina (Grunow) Krammer and Epithemia argus (Ehrenb.) Kütz., in decreasing order of numerical abundance. Cymbopleura laszlorum is believed to be a glacial relic. During the Wisconsin glaciation, the adjacent mountain ranges (Madison, Tobacco Root and Gravely Ranges) were capped with ice.

Odell Spring Creek

Original Description

Valves are elliptic-lanceolate with convex margins and rostrate to subrostrate apices. Length 41–54 µm; width 9.7–11.4 µm. Valves are symmetric with respect to both the apical and transapical axes. The axial area is about three times the width of the raphe and widens gradually towards the central area. The central area is moderately large and variable in shape, most often transversely elliptic to rectangular, sometimes shaped like a bow tie. The raphe is lateral, narrowing towards the ends. Proximal raphe ends are deflected gently towards the ventral margin and tipped with slightly inflated pores. Terminal raphe fissures are hook-shaped and concave towards the dorsal margin. Striae are uniseriate and radiate throughout, 14 in 10 µm at the valve center, up to 22 in 10 µm at the apices. Areolae are also variable in density, 20 in 10 µm in striae at the valve center, up to 30 in 10 µm at the apices. [n = 26 specimens]

  • Basionym
    Cymbopleura laszlorum
  • Author
    Bahls and T.Luna 2018
  • Length Range
    41–54 µm
  • Width
    9.7–11.4 µm
  • Striae in 10µm
    14 at the valve center up to 22 at the apices

Original Images

Cymbopleura Laszlorum Orig Imag 1
Cymbopleura Laszlorum Orig Imag 2
Cymbopleura Laszlorum Orgig Imag 3

Cite This Page

Bahls, L. (2018). Cymbopleura laszlorum. In Diatoms of North America. Retrieved April 18, 2024, from https://diatoms.org/species/cymbopleura-laszlorum

Responses

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