| Alcyonium digitatum | |
|---|---|
 | |
| Alcyonium digitatum | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Cnidaria |
| Class: | Octocorallia |
| Order: | Alcyonacea |
| Family: | Alcyoniidae |
| Genus: | Alcyonium |
| Species: | A. digitatum |
| Binomial name | |
| Alcyonium digitatum | |
Alcyonium digitatum or dead man's fingers is a species of soft coral in the family Alcyoniidae. It is found around the coasts of the northern Atlantic Ocean and other temperate waters such as the South Pacific.
Dead man's fingers is a colonial coral forming clumps of yellow, white or cream-coloured fleshy masses of finger-like lobes. The surface layer include many sclerites which form a crust. [2] The individual polyps are white and translucent, and project from the leathery surface when feeding, giving the colony a furry appearance. [3]
Dead man's fingers is found along the Atlantic coasts of north west Europe from Portugal to Norway, most recently being discovered in the uncharted waters of Jammerbugt bay off the north-west coast of Denmark by a 2020 seafloor mapping project led by explorer Klaus Thymann. [4] The species also occurs in parts of Canada, northeastern coast of the United States, the Gulf of Maine and the Bay of Fundy and the northern waters of New Zealand. [5] The polyps live in colonies attached to bedrock, boulders, stones and occasionally the shells of crabs and gastropods. They are most plentiful in areas with strong water movement and where there is insufficient sunlight for algae to predominate. They are usually found in the sublittoral zone down to about fifty metres. [1] This coral is common around the coasts of Britain and Ireland where Alcyonium glomeratum and Alcyonium hibernicum are also found but these are much rarer and misidentification is unlikely. [3]
The colonies of dead man's fingers are nearly always either male or female, although a small number of hermaphrodite colonies are found. Colony growth occurs mainly in the first half of the year with the polyps becoming inactive in late summer, and the base tissue turning reddish or brownish due to the growth of algae and hydroids on the surface. At this time the gonads are developing and spawning occurs in December and January. Populations have been found to synchronize their gametogenesis and spawning activities. [6] Fertilisation takes place externally and the embryos float for a few days before developing into free swimming larvae. Most of these soon settle on a suitable substrate and new polyps develop but a few may remain in the zooplankton for some time and disperse over a wide area. Colonies have been known to live for twenty years. [6]
The polyps feed at various times of the day with their tentacles extended. They are suspension feeders gathering plankton from the water with the help of cilia, and absorbing oxygen at the same time. [1]
Corals are colonial 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 secrete calcium carbonate to form a hard skeleton.
Scleractinia, also called stony corals or hard corals, are marine animals in the phylum Cnidaria that build themselves a hard skeleton. The individual animals are known as polyps and have a cylindrical body crowned by an oral disc in which a mouth is fringed with tentacles. Although some species are solitary, most are colonial. The founding polyp settles and starts to secrete calcium carbonate to protect its soft body. Solitary corals can be as much as 25 cm (10 in) across but in colonial species the polyps are usually only a few millimetres in diameter. These polyps reproduce asexually by budding, but remain attached to each other, forming a multi-polyp colony of clones with a common skeleton, which may be up to several metres in diameter or height according to species.
Pillar coral is a hard coral found in the western Atlantic Ocean and the Caribbean Sea. It is the only species in the monotypic genus Dendrogyra. It is a digitate coral -that is, it resembles fingers or a cluster of cigars, growing up from the sea floor without any secondary branching. It is large and can grow on both flat and sloping surfaces at depths down to 20 m (65 ft). It is one of the few types of hard coral in which the polyps can commonly be seen feeding during the day.
Fire corals (Millepora) are a genus of colonial marine organisms that exhibit physical characteristics similar to that of coral. The name coral is somewhat misleading, as fire corals are not true corals but are instead more closely related to Hydra and other hydrozoans, making them hydrocorals. They make up the only genus in the monotypic family Milleporidae.
Porites astreoides, commonly known as mustard hill coral or yellow porites, is a colonial species of stony coral in the family Poritidae.
Parazoanthus axinellae, commonly known as the yellow cluster anemone, is a zoanthid coral found on the southern Atlantic coasts of Europe and in the Mediterranean Sea. Zoanthids differ from true sea anemones, in having a different internal anatomy and in forming true colonies in which the individual animals (polyps) are connected by a common tissue, called the coenenchyme.
Novocrania anomala is a species of brachiopod found offshore in the eastern Atlantic Ocean.
Alcyoniidae is a family of leathery or soft corals in the phylum Cnidaria.
Alcyonium glomeratum or red sea fingers is a species of soft coral in the family Alcyoniidae. It is found around the southern and western coasts of Britain and Ireland.
Coralliidae, also known as precious corals, is a taxonomic family of soft corals belonging to the suborder Scleraxonia of the phylum Cnidaria. These sessile corals are one of the most dominant members of hard-bottomed benthic environments such as seamounts, canyons and continental shelves. From this coral family results 69 descendants in which each species plays a key role in forming habitats for a variety of marine species.
Leptogorgia virgulata, commonly known as the sea whip or colorful sea whip, is a species of soft coral in the family Gorgoniidae.
Siderastrea radians, also known as the lesser starlet coral or the shallow-water starlet coral, is a stony coral in the family Siderastreidae. It is found in shallow parts of the western Atlantic Ocean as small, solid mounds or encrusting sheets.
Alcyonium palmatum or red dead man's fingers is a species of soft coral in the family Alcyoniidae.
Stylaster nobilis, the noble coral, is a branching colonial hydroid in the family Stylasteridae.
Alcyonium acaule or Mediterranean sea-finger is a species of soft coral in the family Alcyoniidae. It is found at moderate depths on shaded rocks in the Mediterranean Sea and adjoining parts of the Atlantic Ocean.
Dipsastraea speciosa is a species of colonial stony coral in the family Merulinidae. It is found in tropical waters of the Indian and Pacific oceans.
Alcyonium coralloides, commonly known as false coral, is a colonial species of soft coral in the family Alcyoniidae. It is native to the northeastern Atlantic Ocean and the Mediterranean Sea. In the former location it generally grows as sheets or small lobes but in the latter it is parasitic and overgrows sea fans.
Eunicella singularis, the white gorgonian, is a species of colonial soft coral, a sea fan in the family Gorgoniidae. It is found in the western Mediterranean Sea, Adriatic Sea and Ionian Sea. It was first described in 1791 by the German naturalist Eugenius Johann Christoph Esper.
Media related to Alcyonium digitatum at Wikimedia Commons
Data related to Alcyonium digitatum at Wikispecies