''Pseudodiploria clivosa'', the knobby 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

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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 in shallow water in the West Atlantic Ocean and Caribbean Sea.

Description

The knobby brain coral is a massive coral that either forms hemispherical domes or, particularly in areas of high wave action, forms plates and encrusts the seabed. It can grow to a diameter of about . 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. The surface consists of sharply delineated, convoluted ridges with valleys in between. There is no trough-like groove in the top of the ridge as is the case in the rather similar grooved brain coral ''(Diploria labyrinthiformis)''. The coral polyps are strung along the valley bottoms, each sitting in a little stony cup or corallite. The sides of these have minute walls called

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which come in four different sized cycles. They extend outside the corallites as costae that join one corallite to another but are discontinuous in this species, another distinguishing factor. The colour of the coral is usually some shade of yellowish or greenish brown and is caused by the presence of symbiotic dinoflagellates called

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 ...

in the coral's tissues.

Distribution and habitat

The knobby brain coral is a common species and occurs in southern Florida, the Caribbean Sea and the Bahamas. It is found growing on reefs, in seagrass ''(Thalassia testudinum)'' meadows, in lagoons and sometimes on

mangrove A mangrove is a shrub or tree that grows in coastal saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evolution in severa ...

s. It grows at depths down to about but is most common at depths less than . 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

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, Puerto Rico that date back to the

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Biology

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. The knobby brain coral grows by the budding of new polyps and the deposition of new calcareous material. Growth is very slow and large corals may be over a hundred years old. Sexual reproduction occurs by the release of gametes into the

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. The

planula A planula is the free-swimming, flattened, ciliated, bilaterally symmetric larval form of various cnidarian species and also in some species of Ctenophores. Some groups of Nemerteans also produce larvae that are very similar to the planula, which ...

larvae drift with the currents before settling on the seabed and undergoing metamorphosis into polyps. These begin to secrete their own skeletons and found new colonies.

References

{{Taxonbar, from=Q3332885 faviinae Corals described in 1786