The surface of the dome usually has a number of bulges or knobs but this species is not easy to distinguish from the symmetrical brain coral which tends to have a smoother outline.

[3][4] The knobby brain coral is a common species and occurs in southern Florida, the Caribbean Sea and the Bahamas.

[3][4] The fossilised remains of Pseudodiploria clivosa have been found alongside those of other massive corals Pseudodiploria strigosa, Siderastrea siderea and Solenastrea bouroni in marine deposits in Río Grande de Manatí, Puerto Rico that date back to the Pleistocene.

[5] During the day the polyps of the knobby brain coral are retracted into the corallites but at night they emerge and extend their tentacles to feed.

The zooxanthellae are photosynthetic and up to fifty percent of their production is transferred to the host while they make use of the coral's nitrogenous waste.