''Leiopathes glaberrima'' is a species of black coral of the order Antipatharia found in the

northern Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...

and the Mediterranean Seas deep water habitats. A very slow-growing species, it is among the oldest living animals on the planet.

Description

''L. glaberrima'' is an arborescent coral and grows in a sympodial manner; this means that the original axis stops growing after a while, with one or more side branches forking out randomly, only to stop growing as other branches take over. The skeleton is composed of a spiny keratin-like material, laid down in concentric layers. This is overlain by a layer of living tissue from which the polyps project. Each of these has six unbranched, non-retractile tentacles. Mucus coating the surfaces gives rise to the specific epithet ''glaberrima'', "smoothest".

Distribution

The distribution of ''L. glaberrima'' is not completely known, but it is present in both the Pacific and Atlantic Oceans. It is present off the coasts of Hawaii where it is collected commercially. It is also present in the Mediterranean Sea off the coast of Malta at depths of between where it constitutes a dense coral forest which greatly enhances the biodiversity of the area. It is also known from the northern Gulf of Mexico, where more than one colour form exists.

Ecology

In the deep waters off Malta in the Mediterranean Sea, ''Leiopathes glaberrima'' is the dominant species in what have been called "coral gardens", where it is associated with other scleractinian corals, gorgonians and

zoanthids Zoanthids ( order Zoantharia also called Zoanthidea or Zoanthiniaria) are an order of cnidarians commonly found in coral reefs, the deep sea and many other marine environments around the world. These animals come in a variety of different coloniz ...

. The areas are characterised by strong turbulent currents and the corals grow on steep rocky terraces. The colonies are typically a metre or more high, with four or five per square metre. The majority of ''Leiopathes glaberrima'' colonies have white polyps, but some are orange. Associated animals include

soft corals Alcyonacea, or soft corals, are an order of corals. In addition to the fleshy soft corals, the order Alcyonacea now contains all species previously known as "gorgonian corals", that produce a more or less hard skeleton, though quite different f ...

, gorgonians,

crab Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...

s, stalked barnacles, numerous species of fish, the cushion star ''

Peltaster placenta ''Peltaster'' is a genus of echinoderms belonging to the family Goniasteridae. The genus has almost cosmopolitan distribution In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of ...

'',

squat lobsters Squat lobsters are dorsoventrally flattened crustaceans with long tails held curled beneath the cephalothorax. They are found in the two superfamilies Galatheoidea and Chirostyloidea, which form part of the decapod infraorder Anomura, alongside ...

and the spiny lobster ''

Palinurus elephas ''Palinurus elephas'' is a commonly caught species of spiny lobster from the East Atlantic Ocean and the Mediterranean Sea. Its common names include European spiny lobster, crayfish or cray (in Ireland), crawfish (in England), common spiny lobst ...

''. The ecosystem is easily damaged by deep water fishing activities including trammel nets and long lines which break the colonies or get tangled in them. Although the feeding habits of this species have not been studied, black corals usually grow in areas with steady currents and are fan-shaped, orientating themselves at right angles to the flow. The polyps tend to be expanded all the time, and the mouth can stretch to three times its normal size to accommodate large prey items such as

copepod Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...

s, amphipods and

chaetognaths The Chaetognatha or chaetognaths (meaning ''bristle-jaws'') are a phylum of predatory marine worms that are a major component of plankton worldwide. Commonly known as arrow worms, about 20% of the known Chaetognatha species are benthic, and ca ...

. The surface of the coral is covered by mucus which can also trap food particles; these are then moved towards a mouth by currents caused by

cilia The cilium, plural cilia (), is a membrane-bound organelle found on most types of eukaryotic cell, and certain microorganisms known as ciliates. Cilia are absent in bacteria and archaea. The cilium has the shape of a slender threadlike projecti ...

. This coral is a very slow-growing species, with an estimated growth rate of less than 10 µm per year. A specimen collected from a depth of off Hawaii was estimated by radiocarbon dating in 2006 to have an age of around 2377 years. More recently, another Hawaiian specimen of ''Leiopathes glaberrima'', the central portion of a basal holdfast, was found to have an age of 4265 (±44) years, and is believed to be the oldest recorded marine organism.

References

{{Taxonbar, from=Q4004244 Leiopathidae Animals described in 1788