''Oulophyllia crispa'', sometimes called the intermediate valley coral, is a

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 ...

of stony coral in the

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

Merulinidae. It is native to the tropical western and central Indo-Pacific region. Although this coral has a wide range, it is generally uncommon and seems to be decreasing in abundance, and the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

has rated its conservation status as being "

near threatened A near-threatened species is a species which has been categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature as that may be vulnerable to endangerment in the near future, but it does not currently qualify fo ...

Description

Colonies In modern parlance, a colony is a territory subject to a form of foreign rule. Though dominated by the foreign colonizers, colonies remain separate from the administration of the original country of the colonizers, the '' metropolitan state'' ...

of this coral form massive hemispherical domes, stacks or plates that can be a metre (yard) or more across, but in the

Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; T ...

, it seldom exceeds . The

corallite A corallite is the skeletal cup, formed by an individual stony coral polyp, in which the polyp sits and into which it can retract. The cup is composed of aragonite, a crystalline form of calcium carbonate, and is secreted by the polyp. Corallit ...

s are arranged in broad meandering valleys with acute-edged ridges separating them. The

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 coun ...

are thin and evenly spaced, and slope uniformly to the central columella. The polyps only expand at night; they are large and fleshy and have white-tipped

tentacle In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work main ...

s. The colour of this coral is usually some shade of brown, grey or green, sometimes with contrasting oral discs. This coral is somewhat similar in appearance to ''

Platygyra daedalea ''Platygyra daedalea'', sometimes known as the lesser valley coral, is a colonial species of stony coral in the family Merulinidae. It occurs on reefs in shallow water in the Indo-Pacific region. It is a common species and the International Union ...

''.

Distribution and habitat

This coral is found in the tropical western and central Indo-Pacific region. Its range extends from the Red Sea, Gulf of Aden and East Africa to Australia, Japan, the East China Sea and the island groups of the West Pacific Ocean. It is found on reefs at depths down to about , mostly occurring on subtidal rocks and in lagoons.

Ecology

''Oulophyllia crispa'' is a

zooxanthellate 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 ''Symbi ...

coral that has unicellular

dinoflagellate The dinoflagellates (Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered algae. Dinoflagellates are ...

s embedded in its soft, transparent tissues. These use sunlight to create organic carbon molecules that the coral can use. As this coral grows, the polyps do not divide completely, resulting in several mouths being present in each large corallite. Boring sponges (''Cliona'' spp.),

polychaete worms Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are m ...

and

bivalve molluscs Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...

bore holes into colonies of this coral, causing

bioerosion Bioerosion describes the breakdown of hard ocean substrates – and less often terrestrial substrates – by living organisms. Marine bioerosion can be caused by mollusks, polychaete worms, phoronids, sponges, crustaceans, echinoids, and ...

References

{{Taxonbar, from=Q3936633 Merulinidae Corals described in 1816