''Savalia savaglia'', commonly known as gold 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 colonial false black

coral Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and sec ...

in the family

Parazoanthidae Parazoanthidae is a family of cnidarians. Genera include: * '' Antipathozoanthus'' Sinniger, Reimer & Pawlowski, 2010 * ''Bergia'' Duchassaing & Michelotti, 1860 * '' Bullagummizoanthus'' Sinniger, Ocaña & Baco, 2013 * '' Churabana'' gen. nov. ...

. It is native to the northeastern Atlantic Ocean and the Mediterranean Sea where it often grows in association with a gorgonian. It is extremely long-lived, with a lifespan of 2,700 years, and develops into a large tree-like colony.

Description

''Savalia savaglia'' forms a large, tree-like

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 ''metropole, metropolit ...

. The polyps secrete a horny brown or black skeleton from which they project. They are yellow and about tall. Each polyp has an oral disc at the top surrounded by about thirty tentacles. These are arranged in two whorls and are not pinnate, making it easy to recognise that this species is a zoanthid rather than an

octocoral Octocorallia (also known as Alcyonaria) is a class of Anthozoa comprising around 3,000 species of water-based organisms formed of colonial polyps with 8-fold symmetry. It includes the blue coral, soft corals, sea pens, and gorgonians (sea fans ...

or a member of another order of

Hexacorallia Hexacorallia is a Class (biology), class of Anthozoa comprising approximately 4,300 species of aquatic organisms formed of polyp (zoology), polyps, generally with 6-fold symmetry. It includes all of the stony corals, most of which are Colony (b ...

Distribution

''Savalia savaglia'' is found in the western Mediterranean Sea between the Straits of Gibraltar and Sardinia. It is also found in the Atlantic Ocean, its range including the Canary Islands, Madeira, and the Atlantic coasts of Spain and Portugal. The species is uncommon throughout most of its range, though rather more common in the

Gulf of Corinth The Gulf of Corinth or the Corinthian Gulf ( el, Κορινθιακός Kόλπος, ''Korinthiakόs Kόlpos'', ) is a deep inlet of the Ionian Sea, separating the Peloponnese from western mainland Greece. It is bounded in the east by the Isth ...

and the Sea of Marmara. Its depth range is usually between . Research has shown that its most suitable habitat is a rough sea floor with steeply sloping rocks which are slanting northeastward, at a depth in the range of .

Ecology

A colony of ''Savalia savaglia'' often starts by colonising the surface of a gorgonian such as ''

Paramuricea clavata ''Paramuricea clavata'', the violescent sea-whip, is a species of colonial soft coral in the family Plexauridae. It is found in shallow seas of the north-eastern Atlantic Ocean and the north-western Mediterranean Sea as well as Ionian Sea. This s ...

'' or '' Eunicella singularis''. In time it engulfs these gorgonians and produces its own rigid skeleton, making it self-supporting. It can grow to a height of 2 metres (6 feet) with a trunk diameter of . The skeleton is rich in

histidine Histidine (symbol His or H) is an essential amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated –NH3+ form under biological conditions), a carboxylic acid group (which is in the de ...

and contains the unusual ecdysterone, ajugasterone-C. The growth rate of the colony is slow and

carbon-14 Carbon-14, C-14, or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons. Its presence in organic materials is the basis of the radiocarbon dating method pioneered by Willard Libby and coll ...

dating techniques have given an age of 2,700 years, giving this zoanthid one of the longest lifespans of any organism on Earth. Because of its longevity and its large, rigid three-dimensional skeleton, it is considered to be a habitat modifier, reducing current velocity, stabilising sedimentation and increasing local deposition of fine particles. It also promotes

biodiversity Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic (''genetic variability''), species (''species diversity''), and ecosystem (''ecosystem diversity'') l ...

on the seabed. The polyps of ''S. savaglia'' feed by capturing

plankton Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...

and other particles from the water, and can also absorb dissolved nutrients. Colonies of ''S. savaglia'' are either male or female. At a study site in the northwestern Mediterranean at , there were found to be more female colonies than male. Spawning took place in December when the seawater started to cool. This zoanthid can also reproduce asexually.

References

External links

* * {{Taxonbar, from=Q595042 Invertebrates of Europe Animals described in 1819 Parazoanthidae Cnidarians of the Atlantic Ocean Fauna of the Mediterranean Sea