''Antipathella fiordensis'' 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 ...

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 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 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). Antipa ...

, the black corals, so named because their calcareous skeletons are black. It was first described as ''Antipathes fiordensis'' by the New Zealand zoologist Ken R. Grange in 1990, from material collected in the steep-sided

fiords In physical geography, a fjord or fiord () is a long, narrow inlet with steep sides or cliffs, created by a glacier. Fjords exist on the coasts of Alaska, Antarctica, British Columbia, Chile, Denmark, Förden and East Jutland Fjorde, Germany, Gr ...

Fiordland Fiordland is a geographical region of New Zealand in the south-western corner of the South Island, comprising the westernmost third of Southland. Most of Fiordland is dominated by the steep sides of the snow-capped Southern Alps, deep lakes, ...

in the southeastern

South Island The South Island, also officially named , is the larger of the two major islands of New Zealand in surface area, the other being the smaller but more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman ...

, New Zealand. A 2001 revision of the Antipatheria put this species in the newly-created genus ''Antipathella''.

Description

Black corals have flexible bushy or tree-like forms. They have black skeletons of dense, horny material, covered by a thin layer of living tissue from which the polyps project. Each polyp has six unbranched tentacles and a slit-shaped mouth, and is non-retractable. Normal tentacles are less than long, but this black coral can develop sweeper tentacles up to long, armed with stinging cells, in apparent response to

epiphytic An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphytes grow are called phoroph ...

organisms attempting to grow on the branches. These corals do not contain

zooxanthellae Zooxanthellae is a colloquial term for single-celled dinoflagellates that are able to live in symbiosis with diverse marine invertebrates including demosponges, corals, jellyfish, and nudibranchs. Most known zooxanthellae are in the genus ''Sy ...

in their tissues and thus do not need to live in sunlit places. ''A. fiordensis'' has a 50:50 sex ratio, with no obvious differences between the sexes. Colonies do not reach sexual maturity until they are about 0.7–1.0 m tall, aged at least 30 years. Female colonies produce between 1.3 million and nearly 17 million

oocytes An oocyte (, ), oöcyte, or ovocyte is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in a female fetus in the ovary during female gametogenesis. The female ge ...

each year.

Distribution

''Antipathella fiordensis'' occurs in the seas around New Zealand at depths of from .

Ecology

The fiords where ''A. fiordensis'' grows have nearly vertical rock walls, providing limited sites for attachment of organisms, so many other species live on these corals. One is the snake star '' Astrobrachion constrictum'', which perches and coils its arms tightly around the coral's branches. This snake star is found in a number of places around New Zealand, but always in association with a black coral. It seems to be a mutualistic arrangement: coral polyps are more efficient at catching prey than the unbranched arms of a snake star; the snake star appropriates some of the prey, while also cleaning mucus off the coral and preventing epizoic organisms from settling on it.

References

External links

* ''Antipathella fiordensis'' discussed on

RNZ Radio New Zealand ( mi, Te Reo Irirangi o Aotearoa), commonly known as Radio NZ or simply RNZ, is a New Zealand public-service radio broadcaster and Crown entity that was established under the Radio New Zealand Act 1995. It operates news and cu ...

''Critter of the Week''
7 September 2018
{{Taxonbar, from=Q4006943 Myriopathidae Animals described in 1990 Cnidarians of the Pacific Ocean Endemic fauna of New Zealand Endemic cnidarians of New Zealand