Adamsia palliata
Encyclopedia
Adamsia palliata is a species
of sea anemone
in the family
Hormathiidae
. It is usually found growing on a gastropod shell
inhabited by the hermit crab
, Pagurus prideaux
. The anemone often completely envelops the shell and because of this it is commonly known as the cloak anemone.
in 1981, Manuel applied the name Adamsia carciniopados to this species, attributing it to Otto, 1823. However Cornelius and Ates in 2003 decided that Adamsia palliata was the valid name, attributing it to O.F. Muller
, 1776, and considered A. carciniopados to be a "nomen dubium". The World Register of Marine Species attributes the name to Fabricius
, 1779 and rejects another attribution, Adamsia palliata (Bohadsch
, 1761).
which is housing a hermit crab. The anemone's base is wide and convoluted with lobes that extend around the shell. The edges join together in a suture where the shell is completely encircled. The oral disc and tentacles are orientated downwards beneath the underside of the crab. The basal lobes can extend to about fifteen centimetres while the trunk is only about one centimetre high. The column is fawn tinged with pinkish-purple, paling to white near the parapet. It is covered with vivid magenta spots which are largest in the central portion. There is a narrow pink line round the margin of the parapet and the oral disc and tentacles are white. The tentacles are numerous and about one centimetre long, not fully retractable and arranged in four sub-marginal rows. The mouth is long and oval and protrudes from the disc. When it becomes too large for the shell, the anemone secretes a chitin
ous membrane at its base. This has the effect of increasing the volume of the shell available to the hermit crab which can then inhabit it for a longer period before needing to find a new home. In one instance, on a shell of Gibbula umbilicalis
, this membrane had developed into a pseudo body-whorl as voluminous as the rest of the shell. On the lower part of the column there are specialist cells which emit defensive pink (occasionally white) threads called acontia if the animal is disturbed.
south to the Azores
, in the North Sea
and the Mediterranean Sea
. It occurs wherever its hermit crab host is found, in deep water on sandy flats and particularly favours muddy gravelly bottoms with shell fragments. Off the coast of Norway
it was said to be common at a depth of 15 to 20 fathoms (30 to 40 metres) in 1860.
larva which settles and develops into a juvenile sea anemone. The larva is for some reason drawn to settle on the inner lip of a gastropod shell. At first the larva develops in the same way as a typical sea anemone, but as it grows, its base extends around the gastropod shell until the two lobes meet at the upper side of the lip. The species of shell the anemone chooses varies, and has included Buccinum undatum
, Scaphander lignarius
, and various Trochidae
. It has even been found on a shell of the garden snail Helix aspersa
which had been accidentally washed out to sea.
The shell always seem to be tenanted by the hermit crab Pagurus prideaux
. Occasionally this anemone is found on empty shells, but this may be explained by the fact that the crab will readily abandon its current shell if it finds a larger or better one to move into. Young specimens of the anemone are able to detach themselves from their shell and re-attach themselves elsewhere, such as another shell, a Laminaria
frond or the side of an aquarium
.
between A. palliata and P. prideaux is beneficial to both. The anemone gains a mobile base and access to food scraps while the crab gains the protection against predators
provided by the anemone's nematocysts
. It is not an obligate symbiosis however. The anemone has been kept in an aquarium for an extended period on a rock substrate and in 1969, Maynardi and Rossi found a single example of the hermit crab Pagurus excavatus carrying, on its gastropod shell, a specimen of A. palliata and another of Calliactis parasitica
.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of sea anemone
Sea anemone
Sea anemones are a group of water-dwelling, predatory animals of the order Actiniaria; they are named after the anemone, a terrestrial flower. Sea anemones are classified in the phylum Cnidaria, class Anthozoa, subclass Zoantharia. Anthozoa often have large polyps that allow for digestion of larger...
in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Hormathiidae
Hormathiidae
Hormathiidae is a family of sea anemones in the class Anthozoa.-Genera:Genera in this family include:* Actinauge Verrill, 1883* Adamsia Forbes, 1840* Allantactis Danielssen, 1890* Amphianthus R...
. It is usually found growing on a gastropod shell
Gastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...
inhabited by the hermit crab
Hermit crab
Hermit crabs are decapod crustaceans of the superfamily Paguroidea. Most of the 1100 species possess an asymmetrical abdomen which is concealed in an empty gastropod shell that is carried around by the hermit crab.-Description:...
, Pagurus prideaux
Pagurus prideaux
Pagurus prideaux is a species of hermit crab in the family Paguridae. It is found in shallow waters off the northwest coast of Europe and usually lives symbiotically with the sea anemone Adamsia palliata.-Description:...
. The anemone often completely envelops the shell and because of this it is commonly known as the cloak anemone.
Taxonomy
In a revision of British AnthozoaAnthozoa
Anthozoa is a class within the phylum Cnidaria that contains the sea anemones and corals. Unlike other cnidarians, anthozoans do not have a medusa stage in their development. Instead, they release sperm and eggs that form a planula, which attaches to some substrate on which the cnidarian grows...
in 1981, Manuel applied the name Adamsia carciniopados to this species, attributing it to Otto, 1823. However Cornelius and Ates in 2003 decided that Adamsia palliata was the valid name, attributing it to O.F. Muller
Otto Friedrich Müller
Otto Friedrich Müller, also Mueller was a Danish naturalist.-Biography:Müller was born in Copenhagen. He was educated for the church, became tutor to a young nobleman, and after several years' travel with him settled in Copenhagen in 1767, and married a lady of wealth.His first important works,...
, 1776, and considered A. carciniopados to be a "nomen dubium". The World Register of Marine Species attributes the name to Fabricius
Johan Christian Fabricius
Johan Christian Fabricius was a Danish zoologist, specialising in "Insecta", which at that time included all arthropods: insects, arachnids, crustaceans and others...
, 1779 and rejects another attribution, Adamsia palliata (Bohadsch
Johann Baptist Bohadsch
Johann Baptist Bohadsch was a German professor of botany and pharmacology and a naturalist.-Early life and career:Johann was born in 1724 in Prague. His father was manager of the estates of Count Wenzel von Zwrtby. Johann was educated at a Jesuit seminary where he learned Latin and philosophy...
, 1761).
Description
A. palliata normally lives on the shell of a sea snailSea snail
Sea snail is a common name for those snails that normally live in saltwater, marine gastropod molluscs....
which is housing a hermit crab. The anemone's base is wide and convoluted with lobes that extend around the shell. The edges join together in a suture where the shell is completely encircled. The oral disc and tentacles are orientated downwards beneath the underside of the crab. The basal lobes can extend to about fifteen centimetres while the trunk is only about one centimetre high. The column is fawn tinged with pinkish-purple, paling to white near the parapet. It is covered with vivid magenta spots which are largest in the central portion. There is a narrow pink line round the margin of the parapet and the oral disc and tentacles are white. The tentacles are numerous and about one centimetre long, not fully retractable and arranged in four sub-marginal rows. The mouth is long and oval and protrudes from the disc. When it becomes too large for the shell, the anemone secretes a chitin
Chitin
Chitin n is a long-chain polymer of a N-acetylglucosamine, a derivative of glucose, and is found in many places throughout the natural world...
ous membrane at its base. This has the effect of increasing the volume of the shell available to the hermit crab which can then inhabit it for a longer period before needing to find a new home. In one instance, on a shell of Gibbula umbilicalis
Gibbula umbilicalis
Gibbula umbilicalis, common name the flat top shell, is a species of sea snail, a marine gastropod mollusk in the family Trochidae, the top snails.-Description:The size of an adult shell varies between 10 mm and 22 mm.-Distribution:...
, this membrane had developed into a pseudo body-whorl as voluminous as the rest of the shell. On the lower part of the column there are specialist cells which emit defensive pink (occasionally white) threads called acontia if the animal is disturbed.
Distribution and habitat
A. palliata is found in shallow parts of the northeast Atlantic OceanAtlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
south to the Azores
Azores
The Archipelago of the Azores is composed of nine volcanic islands situated in the middle of the North Atlantic Ocean, and is located about west from Lisbon and about east from the east coast of North America. The islands, and their economic exclusion zone, form the Autonomous Region of the...
, in the North Sea
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...
and the Mediterranean Sea
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...
. It occurs wherever its hermit crab host is found, in deep water on sandy flats and particularly favours muddy gravelly bottoms with shell fragments. Off the coast of Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
it was said to be common at a depth of 15 to 20 fathoms (30 to 40 metres) in 1860.
Biology
A. palliata breeds during the summer months. Several hundred globular golden eggs are ejected into the water column through the mouth and are fertilised externally. Each develops into a planulaPlanula
A planula is the free-swimming, flattened, ciliated, bilaterally symmetric larval form of various cnidarian species. The planula forms from the fertilized egg of a medusa, as the case in scyphozoans and some hydrozoans, or from a polyp, as in the case of anthozoans...
larva which settles and develops into a juvenile sea anemone. The larva is for some reason drawn to settle on the inner lip of a gastropod shell. At first the larva develops in the same way as a typical sea anemone, but as it grows, its base extends around the gastropod shell until the two lobes meet at the upper side of the lip. The species of shell the anemone chooses varies, and has included Buccinum undatum
Buccinum undatum
Buccinum undatum, known as the common whelk, is a large edible marine gastropod in the family Buccinidae, the "true whelks".-Distribution:...
, Scaphander lignarius
Scaphander lignarius
Scaphander lignarius, common name the Woody Canoe-bubble, is a species of sea snail, a bubble snail, a marine opisthobranch gastropod mollusk in the family Scaphandridae.-Distribution:...
, and various Trochidae
Trochidae
The Trochidae, common name top snails, are a taxonomic family of very small to large sea snails, marine gastropod molluscs in the clade Vetigastropoda ....
. It has even been found on a shell of the garden snail Helix aspersa
Helix aspersa
Helix aspersa, known by the common name garden snail, is a species of land snail, a pulmonate gastropod that is one of the best-known of all terrestrial molluscs. The species has been placed in the genus Helix, in all sources between 1774 and 1988 and in most sources until recently...
which had been accidentally washed out to sea.
The shell always seem to be tenanted by the hermit crab Pagurus prideaux
Pagurus prideaux
Pagurus prideaux is a species of hermit crab in the family Paguridae. It is found in shallow waters off the northwest coast of Europe and usually lives symbiotically with the sea anemone Adamsia palliata.-Description:...
. Occasionally this anemone is found on empty shells, but this may be explained by the fact that the crab will readily abandon its current shell if it finds a larger or better one to move into. Young specimens of the anemone are able to detach themselves from their shell and re-attach themselves elsewhere, such as another shell, a Laminaria
Laminaria
Laminaria is a genus of 31 species of brown algae , all sharing the common name "kelp". This economically important genus is characterized by long, leathery laminae and relatively large size. Some species are referred to by the common name Devil's apron, due to their shape, or sea colander, due to...
frond or the side of an aquarium
Aquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...
.
Ecology
The symbiosisSymbiosis
Symbiosis is close and often long-term interaction between different biological species. In 1877 Bennett used the word symbiosis to describe the mutualistic relationship in lichens...
between A. palliata and P. prideaux is beneficial to both. The anemone gains a mobile base and access to food scraps while the crab gains the protection against predators
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
provided by the anemone's nematocysts
Cnidocyte
A cnidocyte, cnidoblast, or nematocyte is a type of venomous cell unique to the phylum Cnidaria . The cnidocyte cell provides a means for them to catch prey and defend themselves from predators. Despite being morphologically simple, lacking a skeleton and usually being sessile, cnidarians prey on...
. It is not an obligate symbiosis however. The anemone has been kept in an aquarium for an extended period on a rock substrate and in 1969, Maynardi and Rossi found a single example of the hermit crab Pagurus excavatus carrying, on its gastropod shell, a specimen of A. palliata and another of Calliactis parasitica
Calliactis parasitica
Calliactis parasitica is a species of sea anemone associated with hermit crabs. It lives in the eastern Atlantic Ocean and Mediterranean Sea at depths between the intertidal zone and . It is up to in size, with up to 700 tentacles, and is very variable in colour. The relationship between C...
.