''Heliofungia actiniformis'' is a solitary

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 mushroom coral, a large polyp

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 ...

Fungiidae The Fungiidae () are a family of Cnidaria, commonly known as mushroom corals or plate corals. The family contains thirteen extant genera. They range from solitary corals to colonial species. Some genera such as '' Cycloseris'' and ''Fungia'' ar ...

. This coral is found in shallow water in the Indo-Pacific region. It 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 ''Sy ...

species. It is a popular coral in the

reef aquarium A reef aquarium or reef tank is a marine aquarium that prominently displays live corals and other marine invertebrates as well as fish that play a role in maintaining the tropical coral reef environment. A reef aquarium requires appropriatel ...

trade; wild populations are threatened by disease,

climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...

, and over-collecting, and the species is considered vulnerable by the IUCN.

Description

Although fixed to the substrate as a juvenile, this coral becomes detached later and is free-living as an adult. It is circular or oval with a diameter of up to and height of . The corallum (stony skeleton) is thick and solid. 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 c ...

(stony ridges) are in several orders. The early order septa are larger than later order ones and have more prominent, lobe-like or triangular teeth. All the septa are granulate, and continue to the underside of the corallum as fine ridges known as costae. There is an attachment scar in the centre of the underside. The polyp is thick and fleshy and has a single mouth surrounded by thick

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 ma ...

s with knobs on the end. The tentacles are nearly always extended and superficially resembles a large sea anemone.

Distribution

''Heliofungia actiniformis'' is native to the eastern Indian Ocean and the central Indo-Pacific region, the northwestern, northern and eastern coasts of Australia, Japan, the China Sea and the island groups of the West Pacific. Its depth range is between about . It usually occurs on reef slopes or on reef flats.

Ecology

''H. actiniformis'' is a zooxanthellate coral, containing tiny photosynthetic, symbiotic organisms in its tissues. During the day these supply the coral with much of its metabolic needs. The coral also feeds 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 ...

which are caught by the tentacles. Besides reproducing sexually by liberating eggs and sperm into the

water column A water column is a conceptual column of water from the surface of a sea, river or lake to the bottom sediment.Munson, B.H., Axler, R., Hagley C., Host G., Merrick G., Richards C. (2004).Glossary. ''Water on the Web''. University of Minnesota-D ...

, this coral sometimes buds off a new polyp. Polyps of ''H. actiniformis'' provide a micro-habitat to a wide range of associated fauna from cleaner shrimps to juvenile fishes.

Aquaculture

Many corals can be increased in number by detaching pieces of a

colony 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' ...

and attaching them to the substrate. That is not possible with large polyp stony corals such as ''Heliofungia actiniformis'', but it is hoped to remedy this by placing collecting devices above them when spawning is about to occur, mixing the eggs and sperm under controlled conditions and nurturing the larvae in tanks. The technique has been successfully applied to ''

Acropora formosa ''Acropora muricata'', commonly called staghorn coral, is a species of acroporid coral found in the Gulf of Aden, the Red Sea, Indian Ocean, Persian Gulf, Australia, central Indo-Pacific, Japan, Southeast Asia, the East China Sea and the ocean ...

''. It is hoped that the resulting offspring will be able to be used to repopulate damaged reefs or to relieve the pressure of collecting corals from the wild for the

trade.

Status

Although this coral is common in some localities, it is vulnerable to the degradation processes which are occurring on coral reefs. It is susceptible to coral diseases and to

coral bleaching Coral bleaching is the process when corals become white due to various stressors, such as changes in temperature, light, or nutrients. Bleaching occurs when coral polyps expel the zooxanthellae ( dinoflagellates that are commonly referred to as a ...

and is likely to be threatened by

. It is heavily collected for the aquarium trade, being one of the top 10 exported corals from Indonesia, the largest exporter of the species.
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In 2005, about 50,000 individuals were collected and exported from Indonesia. For these reasons, 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 nat ...

has assessed its conservation status as " vulnerable".

References

External links

* {{Taxonbar, from=Q529166 Fungiidae Cnidarians of the Pacific Ocean Cnidarians of the Indian Ocean Marine fauna of Asia Marine fauna of Oceania Marine fauna of Southeast Asia Cnidarians of Australia Vulnerable fauna of Asia Vulnerable fauna of Oceania Corals described in 1833 Taxa named by Jean René Constant Quoy Taxa named by Joseph Paul Gaimard