Pseudodiploria strigosa
A slow-growing, long-lived brain coral of the West Atlantic and Caribbean.
Pseudodiploria strigosa, called the symmetrical brain coral, is a colonial stony coral belonging to the family Mussidae. It lives on shallow reefs in the West Atlantic Ocean and Caribbean Sea, growing very slowly and reaching an old age.
This coral forms smooth, flat plates or massive, rounded domes up to 1.8 meters across. Its surface is covered with connected, winding valleys. Polyps sit in cup-like depressions called corallites, each with radial ridges (septa) that extend outside as costae and connect with those of neighboring corallites. The ridges between valleys are smoothly rounded, usually lacking a groove along the top, unlike the similar grooved brain coral (*Diploria labyrinthiformis*). The coral hosts symbiotic dinoflagellate algae (zooxanthellae) in its tissues, which give it a yellowish or greenish brown color, sometimes blue-gray. The valleys are often a paler or contrasting shade.
It grows in shallow parts of the Caribbean Sea, the Bahamas, Bermuda, Florida, and Texas. Probably the most widespread brain coral, it occurs on reefs and sometimes on muddy seabeds where few other corals thrive, at depths down to about 40 meters. Fossil remains of *Pseudodiploria strigosa* have been found alongside those of other massive corals in Pleistocene marine deposits in Río Grande de Manatí, Puerto Rico.
The coral grows about 1 centimeter in diameter per year, so a specimen over a meter across is at least a century old. By day, polyps retract into their corallites; at night, they extend tentacles to feed on zooplankton. The coral also benefits from photosynthetic products produced by its zooxanthellae.
Quick Facts
- Taxon
- Pseudodiploria strigosa
Facts from the source article.
Lore & Background
The symmetrical brain coral forms smooth flat plates or massive hemispherical domes up to 1.8 metres in diameter. Its surface is covered with interlinking convoluted valleys in which the polyps sit in cup-shaped depressions known as corallites. Each corallite has radially arranged ridges called septa that continue outside as costae and link with those of neighboring corallites. The ridges separating the valleys are smoothly rounded and lack a groove along their apex, distinguishing it from the similar grooved brain coral (Diploria labyrinthiformis). The coral hosts symbiotic dinoflagellate algae called zooxanthellae in its tissues, which give the coral its color of yellowish or greenish brown, or occasionally blue-grey; the valleys are often a paler or contrasting color.
Reader's Guide
Pseudodiploria strigosa is probably the most widespread of the brain corals, occurring not only on reefs but also on muddy stretches of seabed where few other corals flourish. It grows in shallow parts of the Caribbean Sea, the Bahamas, Bermuda, Florida, and Texas, at depths down to about 40 metres. The coral grows very slowly, adding about 1 centimetre to its diameter per year, meaning a large specimen over a metre across is at least a century old. During the day the polyps retract inside their corallites, but at night they extend their ring of tentacles and feed on zooplankton. The coral also benefits from the photosynthetic products produced by its zooxanthellae. Fossilized remains of Pseudodiploria strigosa have been found alongside those of other massive corals in marine deposits in Río Grande de Manatí, Puerto Rico dating back to the Pleistocene.
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