Diatoms of North AmericaDiatoms of North America

Anomoeoneis capitata

Bahls 2017

Anomoeoneis Capitata Guide
  • Category
    Symmetric Biraphid
  • Length Range
    37-46 µm
  • Width Range
    12.3-14.3 µm
  • Striae in 10 µm
    17-19
  • Reported As
    Anomoeoneis sphaerophora (Cumming et al. 1995, p. 18, pl. 14, fig. 2 (not figs 1 and 3))

Identification

Anomoeoneis capitata LM1 Anomoeoneis capitata LM2 Anomoeoneis capitata LM3 Anomoeoneis capitata LM4 Anomoeoneis capitata LM5 Anomoeoneis capitata LM6
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Description

Valves are elliptic with capitate apices. The axial area is narrow and straight. A longitudinal column of prominent areolae borders the axial area on each side. The central area is faint, lyrate and asymmetric, reaching the valve margin on one side. Ghost striae in the central area are nearly as prominent as regular striae, making the central area difficult to see. A very small, round central nodule might be mistaken for a central area at first glance. The raphe is weakly lateral. Proximal raphe ends are tear-drop shaped and deflected very slightly to the same side. Terminal raphe fissures are deflected sharply in the same direction as the proximal raphe ends. Striae are weakly radiate, becoming parallel then convergent at the apices. Areolae are evenly spaced and number about 30 in 10 µm.

Autecology

This taxon has been recorded from two prairie streams in eastern Montana (types) and from Flat Lake near Kamloops, British Columbia (Cumming et al. 1995, plate 14, fig. 2, identified as Anomoeoneis sphaerophora). The pH of Flat Lake ranged from 9.5-9.7 and conductivity from 3,748-4,658 µS/cm. The dominant cations were sodium, potassium and magnesium; the dominant anions were sulfate and chloride (Cumming et al. 1995).

Anomoeoneis Capitata Monoensis
Credit: Loren Bahls
Anomoeoneis capitata (top row) compared to Anomoeoneis monoensis (bottom two rows).
Anomoeoneis Plate 1 Capitata
Credit: Loren Bahls
Anomoeoneis taxa from western North America. Anomoeoneis capitata is shown in fig. 5

Original Description

Valves are elliptic with capitate apices. Valve length 37-46 µm; valve width 12.3-14.3 µm. The axial area and raphe branches are narrow and straight. A longitudinal row of prominent areolae borders the axial area on each side. The central area is very small and roundish. External proximal raphe ends are tear-drop shaped and deflected very slightly to one side. Terminal raphe fissures are deflected sharply in the same direction as the proximal raphe ends. Striae are radiate, becoming parallel at the apices, 17-19 in 10 µm. Areolae number about 30 in 10 µm. [n=9]

  • Author
    Bahls 2017
  • Length Range
    37-46 µm
  • Width
    12.3-14.3 µm
  • Striae in 10µm
    17-19

Original Images

Anomoeoneis Capitata Figs1 6

Cite This Page

Bahls, L. (2018). Anomoeoneis capitata. In Diatoms of North America. Retrieved April 23, 2024, from https://diatoms.org/species/anomoeoneis-capitata

Responses

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