''Pseudodiploria strigosa'', the symmetrical brain coral, is a

colonial Colonial or The Colonial may refer to: * Colonial, of, relating to, or characteristic of a colony or colony (biology) Architecture * American colonial architecture * French Colonial * Spanish Colonial architecture Automobiles * Colonial (1920 au ...

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

stony coral Scleractinia, also called stony corals or hard corals, are marine animals in the phylum Cnidaria that build themselves a hard skeleton. The individual animals are known as polyps and have a cylindrical body crowned by an oral disc in which a mo ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Mussidae Mussidae is a family of stony coral in the order Scleractinia. Following a taxonomic revision in 2012, the family is now restricted to species found in the Atlantic Ocean, with Pacific species transferred to the new family Lobophylliidae. Many ...

. It occurs on reefs in shallow water in the West Atlantic Ocean and Caribbean Sea. It grows slowly and lives to a great age.

Description

The symmetrical brain coral forms smooth flat plates or massive hemispherical domes up to in diameter. The surface is covered with interlinking convoluted valleys in which the polyps sit in cup-shaped depressions known as corallites. Each of these has a number of radially arranged ridges known as

septa The Southeastern Pennsylvania Transportation Authority (SEPTA) is a regional public transportation authority that operates bus, rapid transit, commuter rail, light rail, and electric trolleybus services for nearly 4 million people in five c ...

which continue outside the corallite as costae and link with those of neighbouring corallites. The ridges separating the valleys are smoothly rounded and do not usually have a groove running along their apex as does the rather similar grooved brain coral (''Diploria labyrinthiformis''). The coral has symbiotic dinoflagellate

alga Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

called

zooxanthella Zooxanthellae is a colloquial term for single-celled dinoflagellates that are able to live in symbiosis with diverse marine invertebrates including demosponges, corals, jellyfish, and nudibranchs. Most known zooxanthellae are in the genus '' Sym ...

in its tissues and it is these which give the coral its colour of yellowish or greenish brown, or occasionally blue-grey. The valleys are often a paler or contrasting colour.

Distribution and habitat

The symmetrical brain coral grows in shallow parts of the Caribbean Sea, the Bahamas, Bermuda, Florida and Texas. It is probably the most widespread of the brain corals and not only occurs on reefs but also sometimes on muddy stretches of seabed where not many other corals flourish. It grows at depths down to about . The fossilised remains of ''Pseudodiploria strigosa'' have been found alongside those of other massive corals, ''

Pseudodiploria clivosa ''Pseudodiploria clivosa'', the knobby brain coral, is a colonial species of stony coral in the family Mussidae. It occurs in shallow water in the West Atlantic Ocean and Caribbean Sea. Description The knobby brain coral is a massive coral that ...

'', '' Siderastrea siderea'' and '' Solenastrea bouroni'', in marine deposits in

Río Grande de Manatí The Manatí River (Spanish: Río Grande de Manatí) is a river in Puerto Rico, which flows through several northern municipalities of the island. The river is named after the municipality of Manatí where the river mouth is located. Description ...

, Puerto Rico that date back to the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...

Biology

The symmetrical brain coral grows very slowly adding about to its diameter in a year. This means that a large specimen over a metre (yard) across is at least a century old. In the day time the polyps retract inside their corallites but at night they extend their ring of tentacles and feed on

zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

. The coral also benefits from the photosynthetic products produced by the

zooxanthellae Zooxanthellae is a colloquial term for single-celled dinoflagellates that are able to live in symbiosis with diverse marine invertebrates including demosponges, corals, jellyfish, and nudibranchs. Most known zooxanthellae are in the genus ''S ...

References

{{Taxonbar, from=Q14191622, from2=Q1999992 Faviinae Corals described in 1846