• Category
  • Length Range
    33.5-46.4 µm
  • Width Range
    7.9-9.6 µm
  • Striae in 10 µm
    13-16 (dorsal), 15-18 (ventral), more widely spaced at valve center and closer together at the ends
  • Reported As
    Cymbopleura naviculiformis var. laticapitata (Krammer 2003, p. 57, plate 79, figs 1-12)

Identification

Description

Valves are lanceolate and somewhat dorsiventral, with broadly subrostrate to subcapitate apices. Dorsal margins are moderately convex; ventral margins are weakly convex to almost straight. The axial area, located near the valve mid-line, widens gradually to merge with a large, rounded central area. The central area is three-fifths to three-quarters the valve width. The raphe is lateral, becoming filiform to reverse-lateral at the proximal ends, which are weakly expanded and deflected toward the ventral margin. Terminal raphe fissures are deflected dorsally. Striae are radiate and finely punctate. Areolae are difficult to resolve in LM.

This taxon is part of a holarctic species complex that includes C. linearis, C. fluminea, C. naviculiformis and C. sublanceolata. Krammer (2003) treats it as a variety of C. naviculiformis. It was elevated to the rank of species (Bahls 2014) based on recognition of it as being morphologically distinct from C. naviculiformis, as well as from other species in the complex.

Autecology

Cymbopleura maggieae has been recorded from four ponds, small lakes, and wet meadows in Montana, Oregon and Washington. Krammer (2003) reports this taxon (as C. naviculiformis var. laticapitata) from a "moory bog" in Swedish Lapland.

Loudon Lake2
Credit: Ryan Davis, Adventurers and Scientists for Conservation
Loudon Lake, Okanogan County, Washington: home of Cymbopleura maggieae.

Original Description

Description.—Valves are lanceolate and dorsiventral with rostrate to subrostrate apices. Dorsal margins are moderately arched, ventral margins are weakly convex to almost flat. Valve length 33.5-46.4 μm; valve width 8.1-9.6 μm. Length/width ratio is 3.9-5.0. Axial area, just below the apical axis, widens gradually to merge with a very large rounded central area. Central area is three-fifths to threequarters of the valve width. The raphe is lateral, becoming filiform to reverse-lateral at the proximal ends, which are deflected toward the ventral margin and tipped with weakly expanded pores. Terminal raphe fissures are deflected dorsally. Striae are radiate and very finely punctate, 13-16 in 10 μm (dorsal), 15-18 in 10 μm (ventral). A few striae are more widely spaced at valve center and more closely spaced near the apices.

  • Author
    L.L.Bahls 2014
  • Length Range
    33.5-46.4 µm
  • Width
    8.1-9.6 µm
  • Striae in 10µm
    13-16 dorsal, 15-18 ventral

Original Images

Cymbopleura maggieae orig illus

Cite This Page

Bahls, L. (2015). Cymbopleura maggieae. In Diatoms of North America. Retrieved July 21, 2018, from https://diatoms.org/species/cymbopleura_maggieae

Responses

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