''Plumapathes pennacea'' 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 ...

black coral Antipatharians, also known as black corals or thorn corals, are an order of soft deep-water corals. These corals can be recognized by their jet-black or dark brown chitin skeletons, surrounded by the polyps (part of coral that is alive). Antipat ...

in the order

Antipatharia Antipatharians, also known as black corals or thorn corals, are an order of soft deep-water corals. These corals can be recognized by their jet-black or dark brown chitin skeletons, surrounded by the polyps (part of coral that is alive). Antipat ...

. It is found in the tropical Indian, Pacific and Atlantic Oceans in deep reef habitats where it forms part of a biologically diverse community.

Description

Black corals are so called because the main axial skeleton is made of a spiny,

keratin Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. Alpha-keratin (α-keratin) is a type of keratin found in vertebrates. It is the key structural material making up scales, hair, nails, feathers, ho ...

-like substance called "antipathin" which is a dark brownish-black. This

colonial Colonial or The Colonial may refer to: * Colonial, of, relating to, or characteristic of a colony or colony (biology) Architecture * American colonial architecture * French Colonial * Spanish Colonial architecture Automobiles * Colonial (1920 au ...

coral has a bushy, two dimensional form and grows out of a holdfast firmly anchored to a rock. It can grow to tall and a similar width. The slender branches fork at intervals and divide pinnately, and the smallest pinnules are a few centimetres long and close together, forming a feather-like effect. The polyps are golden brown, brown or blackish, the ones on the pinnules being paler in colour; they may make the axis appear dark red. The size and shape of the polyps vary across the colony, with the polyps most distant from the holdfast being more elongate than the others. Each polyp has six, non-retractile, unbranched tentacles.

Distribution and habitat

''Plumapathes pennacea'' is found in tropical parts of the Indian, Pacific and Atlantic Oceans; it occurs as deep as but is most common between , and even shallower than this in caves and under dark overhangs. It is present in the Caribbean Sea, the Bahamas and southern Florida, but not in Bermuda.

Ecology

A number of other organisms live on this coral or are associated with it. Algae,

hydroids Hydroids are a life stage for most animals of the class Hydrozoa, small predators related to jellyfish. Some hydroids such as the freshwater '' Hydra'' are solitary, with the polyp attached directly to the substrate. When these produce buds ...

and

bryozoa Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic invertebrate animals, nearly all living in sedentary colonies. Typically about long, they have a special feeding structure called a ...

ns settle and grow on the branches, and several species of shrimps, stalked barnacles, molluscs and

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of ...

are associated with it, many as symbionts with some hiding among the branches, and others feeding on the polyps. The living tissue of the coral may grow over the surface of the black coral barnacle ('' Oxynaspis gracilis''). Growth rates of black corals are low and this coral lives for thirty or more years.

References

{{Taxonbar, from=Q4005951 Myriopathidae Cnidarians of the Atlantic Ocean Cnidarians of the Indian Ocean Cnidarians of the Pacific Ocean Cnidarians of the Caribbean Sea Marine fauna of Asia Marine fauna of Oceania Marine fauna of North America Anthozoa of the United States Corals described in 1766 Taxa named by Peter Simon Pallas