Diagnostic description

This species is said to differ from the type (Amphorotia clevei) by having distinct marginal spines and projections from both sides of the frustule. These bifurcating spines have been used as the main character to separate this species from others but examination of specimens of A. clevei from Lake Ladoga revealed similar kinds of very stout spines.

Comparison of the spines from the two species does shows some differences, such that A. clevei has spines which are shorter and less regularly placed, while those of A. hispida are longer, thinner and most often occur in sets of three on the dorsal margin.

In addition, the bifurcating spines of hispida are orientated at a greater angle away from the valve centre than clevei leading one to suspect that in A. clevei the spines would not be visible in the LM.

These differences allow a separation of the two taxa, along with the greater number of the more usual spines and the shorter raphe.