Caribbean Coral Diaries – Psuedodiploria strigosa

Diploria strigosa

The Symmetrical Brain Coral, Psuedodiploria strigosa is a common sight for snorkelers and scuba divers in the Caribbean. This coral grows into round brain like colonies and can be found in the very shallowest part of a reef, down to 100 feet (30m) deep.
There are three species of Diploria found in the Caribbean, each with its own unique characteristic. P. strigosa has a smooth surface compared to P. clivosa, the Knobby brain coral. And P. strigosa has narrow rounded ridges as opposed to the wide grooved ridges of Diploria labyrinthiformis.

1. Diploria clivosa, Knobby Brain Coral. 2. Diploria strigosa, Symmetrical Brain Coral 3. Diploria Labyrinthiformis, Grooved Brain Coral

The ridges of P. strigosa form long symmetrical valleys which are often connected in the center of the colony. These valleys are between 6-9 mm wide and upon closer inspection, the ridges have distinct grooves from the top to the bottom of the ridge.
One possible confusion is mistaking P. strigosa for Colpophyllia natans. Both of these corals grow into large boulders and have a similarly convoluted brain pattern. However, once you look closer at grooves in the ridges you can quickly tell them apart.

The ridges of Colpophyllia have grooves that run from the top of the ridge down through the center of the valley. The fine grooves on P. strigosa run from the top of the ridge to the bottom without the same distinct groove in the center of the valley. The ridges and valleys of Colpophyllia are also wider than Diploria.
The Symmetrical Brain Coral P. strigosa is found in most reef environments especially shallow slopes and lagoons. It is found in purple-brown, gray or greenish with green or gray valley floors.