Identification

Description

Valves are elliptic-lanceolate with rounded apices. The valve face is flat, and at the margin, sharply bent onto the mantle. Striae are radiate throughout; a few shortened striae may be present around the central area. Striae are uniseriate and composed of fine, rounded to elliptic areolae. Internally, interstriae are slightly elevated and the areolae are covered with hymenes. The axial area is narrow and linear. The central area is large and circular or transversely elliptic. The central nodule is distinctly thickened on the internal side of the valve. The raphe is linear. Externally, the proximal and the distal raphe ends are pinhole-shaped. The distal raphe ends do not extend onto the valve mantle, that is, the raphe terminates on the valve face. Internally, the raphe is positioned on elevated sternum. Distal raphe fissures terminate with a helictoglossa. Copulae are open, with one row of pores.

Autecology

So far, Cavinula maculata has been found in a few creeks in South Carolina and Delaware. These creeks have slightly acidic, low condictivity and low-nutrient water.

Original Description

  • Author
    Potapova et al. 2014
  • Length Range
    25-41 µm
  • Width
    15-20 µm
  • Striae in 10µm
    20-25

Original Images

Cavinula maculata orig illus
Cavinula maculata orig descr

Cite This Page

Potapova, M. (2014). Cavinula maculata. In Diatoms of North America. Retrieved July 22, 2018, from https://diatoms.org/species/cavinula_maculata

Responses

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