Genus Petrosaspongia Bergquist, 1995

Definition: Unarmoured Thorectinae with a dense secondary fibre reticulum rendering these sponges hard and incompressible. Very thin fibres, which seem to correspond to a tertiary network, are present in some places. Slightly modified from Cook and Bergquist (2002)

Type species: Petrosaspongia nigra Bergquist, 1995 by monotypy.