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Classification of Black Coral

Black corals are sedentary colonial animals in the same phylum as jellyfish. Their complete taxonomy is: kingdom Animalia, phylum Cnidaria, class Anthozoa, subclass Hexacorallia and order Antipatharia. While closely resembling sea fans, Gorgonians are in a different order: Octocoralia. Unlike stony, reef-building coral, which secrete a calcium carbonate skeleton, black coral secrete a skeleton of the polysaccharide chiton and protein. Chiton also forms the hard outer skeleton of insects, crabs, shrimps and lobsters. Black corals have a worldwide distribution, but are found primarily in deep tropical waters. They are commonly harvested and fashioned into jewelry. Black corals are the official state gem of Hawaii.

Phylum Cnidaria
- Black coral is in phylum Cnidaria. All Cnidarians are carnivores that catch prey using nematocysts or cnidocysts. These are fluid-filled capsules that contain a threadlike structure that stings and captures prey. After the prey is captured, it first undergoes extracellular digestion outside of the cells to break down large food particles, then intracellular digestion in the gut completes the breakdown of food. Cnidarians have no brain or true nerves, but they do have a nerve net.
Class Anthozoa
- All anthozoans are solitary or colonial polyps with no medusa stage, setting them apart from jellyfish. Anthozoan guts are partitioned by septa, increasing the surface area available for digestion. Other anthozoans include sea anemones, stony corals and sea fans.
Subclass Hexacoralia
- Hexacorals are distinguished by the presence of polyps with six, hexa tentacles. Anemones are examples of soft hexacorals. Stony and black corals are hard hexacorals.
Order Antipatharia
- Order Antipatharia includes all black corals. Black corals, or antipatharians, are characterized by black skeletons made of chiton and protein. These corals grow in colonies ranging from a few centimeters to several meters in height. The colony may form as a single stem or into a complex branching pattern made of stems, branches and pinnules. The base stem is anchored to the sea floor or rock by a basal plate or hook. While the skeletons are largely black, some have golden coloration at the apex of the branches. The polyps themselves may be yellow, orange, pink, white, brown or green. They have six to 12 septa dividing their gastric cavity and a weak muscular system. Their nematocysts are termed nematosores, as they are rounded, wartlike structures. Each separate colony is all of one sex, either male or female. When cut, you can observe growth rings in the skeleton, which indicate the age of the colony.
Black Coral Families
- There are seven families of black coral: Antipathidae, Aphanipathidea, Cladopathidae, Leiopathidae, Myriopathidae, Sylopathidae and Schizopathidea. Within these families, there are 42 genera and over 200 species.

Nature