Shell stock
| Shell stock | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Anemone hermit crab ( Pagurus prideaux ) with a shell on which there is a contracted mantle line (the purple-spotted area). |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Adamsia palliata | ||||||||||||
| ( Fabricius , 1779) |
The mantle common ( Adamsia palliata ) is a species of sea anemone that colonizes snail shells. Its name is derived from the fact that it grows around these shells and thus forms a "coat".
features
The "body" of the mantle actinic is formed by the ectoderm , endoderm and mesogloea and goes from the mouth disk at the upper end to the basal foot disk. It is dirty white, with pink, lavender, and purple spots, and very flattened. If necessary, the anemone can contract, that is, it retracts its tentacles almost completely.
The mouth opening is oval and can reach a diameter of up to five centimeters. It is surrounded by several, circular rows of tentacles. The approximately 384 white tentacles are up to one centimeter long. Just below the mouth opening, which is lighter than the body, there is a thin, pink ring.
The mantle share sets itself upside down on the underside of snail shells. Their tentacles sweep across the sea floor like a broom and can take up food in this way. With its base disk, it grows around the shell, with the base disk edges colliding again on the upper side of the housing when completely encased. The foot disk can reach a diameter of up to fifteen centimeters and is colored white to almost chestnut brown, also with pink and purple spots. The preferred species of snail, on whose empty shell the mantle share line settles alone, rarely in pairs, can vary. Examples are the whelk ( Buccinum undatum ), Scaphander lignarius , and several top snails (Trochidae). These shells are mostly populated by the anemone hermit crab ( Pagurus prideaux ); but there are also other Pagurus species.
When threatened or to acquire prey, A. palliata shoots violet, rarely white, poisonous nettle threads ( nematocysts ) from the basal area.
distribution
One finds A. palliata especially on muddy to sandy soft floors two hundred meters to a maximum depth of the sea.
It occurs in the North Sea, the northeast Atlantic to south of the Azores and in the Mediterranean.
development
During the summer months, Adamsia palliata releases several hundred egg cells into the sea through its mouth. These are fertilized in the water and planula larvae develop . These in turn develop into juvenile sea anemones and look for a suitable host , which they then grow around.
Symbiosis with Pagurus prideaux
The symbiosis between Pagurus prideaux and Adamsia palliata is an ectosymbiosis . The symbiosis is not obligatory, which means that the symbionts do not depend on one another. There were A. palliata -Exemplare observed that survived for years without the partner.
The main advantages for the anemone are mobility. This benefits it as an increased radius of action when catching prey and as an expanded habitat, as it can settle with the help of the hermit on muddy soil in which it would otherwise settle . In addition, the hermit's movement improves the oxygen supply.
The feeding behavior of the crab has another advantage: the hermit crab stirs up the sand around itself to filter out food, which also benefits the diet of the mantle common.
P. prideaux particularly benefits from the nettle cells of the mantle common line. When threatened, the sea anemone shoots nettle threads that stick to the snail shell for several minutes, thus providing adequate protection.
When the mantle share becomes too big, it expels a chitin-containing secretion that enlarges the shell. This also has the advantage for the anemone recluse that it can live longer in the shell, which means that the symbiotic couple does not have to relocate. In some cases, the shell of the snail itself completely dissolves and the actinia itself forms the shell for the crab.
The coexistence of the symbionts goes so far that P. prideaux sometimes moves "his" coat line when moving the housing.
Taxonomy
The taxonomy of the species has been controversial since the 1980s. After it had been led for centuries under the species name palliata , RL Manuel assigned it to the name Adamsia carciniopados AW Otto, 1823, in his work "British Anthozoa " in 1981 for nomenclature reasons . The name palliata originally comes from a publication by Johann Baptist Bohadsch , which, however, has been suppressed by the ICZN for nomenclature purposes because not all of the names in it are binary (Opinion 185). Cornelius and Ates 2003, however, then pleaded that the name Adamsia palliata should be preserved. According to them, before Otto 1823, OF Müller had used the name palliata 1776 and thus made it available in nomenclature in their opinion. The “World Register of Marine Species” instead ascribes the name Adamsia palliata to Fabricius , 1779, and thus follows the opinion of Daphne G. Fautin in “Hexacorallians of the world”.
Individual evidence
- ↑ Wissenschaft online , accessed on January 17, 2013.
- ↑ Actiniaria.com , accessed on January 18, 2013
- ↑ Biology School Lexicon , accessed on January 19, 2013
- ^ RL Manuel (1981): British Anthozoa. Synopses of the British Fauna (New Series) 18: 1-241.
- ↑ International Commission on Zoological Nomenclature (1944): Opinion 185. Suppression of Bohadsch (JB), De quibusdam animalibus marinis, 1761, and of the German translation thereof published by Leske (NG) in 1776. Opinions and Declarations Rendered by the International Commission on Zoological Nomenclature 3: 39-50.
- ^ PFS Cornelius & RML Ates (2003): On the name of the hermit-crab anemone, Adamsia palliata (OV Müller, 1776). Zoological Negotiations Leiden 345: 85-87.
- ^ Adamsia palliata at WoRMS
- ↑ synonymy of Adamsia palliata
Bibliography and web links
- Malien Laurien: symbiosis between hermit crab and sea anemone . Departmental thesis in biology and environmental studies, Gleisdorf 2011
- Encyclopedia of Life , accessed on January 17, 2013.