• Category
  • Length Range
    12-62 µm
  • Width Range
    4-10 µm
  • Striae in 10 µm



Valves are semi-lanceolate to semi-elliptical. The dorsal margin is smoothly arched and the ventral margin is concave. Valve ends are narrowly rounded. The axial area is narrow. The raphe is arched and positioned toward the ventral margin. The proximal and distal ends of the raphe are both dorsally deflected. Dorsal fascia are distinct and round to elliptical. The dorsal fascia are typically “closed” to the axial area and dorsal margin by a row of short striae. The ventral fascia are typically longer (in the apical axis) than dorsal fascia. The ventral fascia extend to the ventral margin. Dorsal striae are weakly radiate in the central area, becoming more radiate at the apices. The dorsal striae are interrupted by intercostal ribs. A thickened, hyaline bar is often visible on the dorsal margin separating valve face and mantle. The ventral striae are uninterrupted. The ventral striae are radiate in the middle, convergent toward the apices, and consist of a single areola.

Original Description

Frustulis sparsis lanceolatis acutis, apicibus hyalinis, binalim copulatis, opposite incurvatis, luteo-fuscis, medio subinflatis et macula hyalina orbiculari notatis.

Unter schwarzbraunem Schaume, der sich am Uter eines kleinen Baches bei Bruckdorf unweit Halle gebildet hatte, sie war noch mit Frustulia acuminata vermischt und schein ganz bewegungslos.

  • Basionym
    Frustulia copulata
  • Author
    Kütz. 1833

Original Images

Kutzing 1833 Zoom    Copy
Kutzing 1833 Description

Cite This Page

Stepanek, J., Kociolek, P. (2011). Amphora copulata. In Diatoms of North America. Retrieved June 21, 2024, from https://diatoms.org/species/amphora_copulata


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