Alcyonacea

Tree - Soft Coral

The soft corals ( Alcyonacea ) are an order of Octocorallia within the Anthozoa ( Anthozoa ). There are animal colonies consisting of many individual polyps.

Features

They grow branched, tree -shaped, lobed, crusty or finger- shaped. The Einzelpolyp, like all animals of the subclass ( Octocorallia ) 8 pinnate tentacles, and the stomach area is 8 longitudinal walls ( septa ) divided into eight chambers. In many species, the colonies have even regressed over hose polyps ( Siphonozoide ) whose job it is to pump water into the body of the colony or deflate. The soft corals can stretch and thereby stabilize.

In contrast to the stony corals ( Scleractinia ) from the subclass Hexacorallia soft corals have no solid calcareous skeleton, but have mostly as strengthening elements small spicules ( sclerites ) in the body.

The living in the sunny shallow water species live in symbiosis with unicellular symbiotic algae ( zooxanthellae ).

Soft corals are predominantly of brown, yellow, or greenish color. Living in deeper regions or in the shade under rocky overhangs species are often bright red, orange or purple.

Dissemination

The soft corals are found worldwide in all oceans, but most species live in warm, tropical seas in shallow water. But even in the deep sea and in the Antarctic Ocean, there are some species. The Dead Sea Hand is the only coral in the North Sea.

System

The soft corals belonging to the eight-rayed flowers animals are only distantly related to the reef-building stony corals ( Scleractinia ). The classification of soft corals is very unclear. The absence of fossils and the variability of growth forms makes it impossible so far to understand the actual evolution of the soft corals.

• Order soft corals ( Alcyonacea Lamouroux, 1816) " Subordination " or informal group Alcyoniina Lamouroux, 1812 Family leather corals ( Alcyoniidae ) Lamouroux, 1812
• Family tree soft coral ( Nephtheidae Gray, 1862)
• Family Nidaliidae Gray, 1869
• Family Xeniidae Wright & Studer, 1889

• Family Haimeidae Wright, 1865
• Family Taiaroidae Bayer & Muzik, 1976

• Family Anthothelidae Broch, 1916
• Family Briareidae Gray, 1859
• Family Coralliidae Lamouroux, 1812
• Family Melithaeidae Gray, 1870
• Family Paragorgiidae Kükenthal, 1916
• Family Parisididae Aurivillius, 1931
• Family Subergorgiidae Gray, 1859

• Family Acrossotidae Bourne, 1914
• Family Clavulariidae Hickson, 1894
• Family Coelogorgiidae Bourne, 1900
• Family Cornulariidae Dana, 1846
• Family Pseudogorgiidae Utinomi & Harada, 1973
• Family Tubiporidae Ehrenberg, 1828

• Family Chrysogorgiidae Verrill, 1883
• Family Dendrobrachiidae Brook, 1889
• Family Ellisellidae Gray, 1859
• Family Ifalukellidae Bayer, 1955
• Family Isididae Lamouroux, 1812
• Family Primnoidae Gray, 1857

• Family Acanthogorgiidae Gray, 1859
• Family Gorgoniidae Lamouroux, 1812
• Family Keroeididae Kinoshita, 1910
• Family Plexauridae Gray, 1859

In 2006, a group looked at the Australian Weichkorallentaxonom Philip Alderslade using mitochondaler the DNA affinity of 103 genera of Octocorallia. The analysis covered 28 families of soft corals, sea pens ( Pennatulacea ) and the Blue Coral ( Heliopora coerulea ) and came to the conclusion these are the Alcyoniina and not a monophyletic taxon. Instead, they form a large clade together with the Holaxonia and some smaller groups. The Calcaxonia form the second along with the sea pens and Blue Coral. A third consists of smaller, lesser-known groups. Untertaxa of soft corals, such as the Scleraxonia that stolonifera and many families are polyphyletic and are allocated to the new clades. A revision of the Alcyonaria is necessary.

Aquarium maintenance

Many soft corals can be kept in saltwater aquariums and are easier for beginners to keep as stony corals.