Valves semi-lanceolate to semi-elliptical, dorsal margin smoothly arched, ventral margin concave. Valve ends narrowly rounded. Axial area narrow, raphe arched and positioned towards the ventral margin with proximal and distal ends deflected dorsally. Dorsal fascia distinct, round to elliptical and typically “closed” to the axial area and dorsal margin by a row of short striae. Ventral fascia typically longitudinally wider than dorsal and extending to the ventral margin. Dorsal striae weakly radiate in central area becoming more radiate at apices, and broken longitudinally by intercostal ribs. Thickened hyaline bar often visible on the dorsal margin separating vale face and mantle. Ventral striae uninterrupted, radiate in the middle, becoming convergent towards the apices and consisting 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

EMAP Assessment

EMAP Distribution

Amphora Copulata 10 Copy
Map 10

Response Plots

Amphora Copulata Copy

Cite This Page

Stepanek, J, and Kociolek, P. (2011). Amphora copulata. In Diatoms of North America. Retrieved July 20, 2018, from


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.