| Cerianthus membranaceus | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Cnidaria |
| Subclass: | Ceriantharia |
| Order: | Spirularia |
| Family: | Cerianthidae |
| Genus: | Cerianthus |
| Species: | C. membranaceus |
| Binomial name | |
| Cerianthus membranaceus | |
| Synonyms | |
List
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Cerianthus membranaceus, the cylinder anemone or coloured tube anemone, is a species of large, tube-dwelling anemone in the family Cerianthidae. It is native to the Mediterranean Sea and adjoining parts of the northeastern Atlantic Ocean.
Cerianthus membranaceus is a large, tube-dwelling anemone. The oral disc can have a diameter of up to 40 cm (16 in). There are two whorls of tentacles, amounting to about two hundred tentacles in all. Those in the outer whorl are long and slender and armed with cnidocytes (stinging cells) and are used for catching prey. Tentacles in the inner whorl are shorter and function to transfer captured food to the central mouth. The tentacles are sometimes banded and come in an array of colours; white, yellow, orange, green, brown, blue, black, purple and violet. The colour of the inner whorl often contrasts with that of the outer whorl. [2]
The column of this tube anemone secretes mucus in which is embedded a unique type of cnidocytes that mesh together to form a fibrous structure. Sand and other particles adhere to this and it forms a leathery, protective tube up to 40 cm (16 in) in length. There is no pedal attachment and the lower end of the tube is buried in the soft substrate. The tube is open at the base which allows for escape of water when the animal retreats into the tube. [2]
Cerianthus membranaceus is found on the seabed in shallow water in the Mediterranean Sea, the northern Adriatic Sea and the northeastern Atlantic Ocean, its range extending as far north as Britain. It occurs on sandy or silty substrates where its tube is buried vertically in the sediment. [2] In the Mediterranean, it principally occurs in areas with high levels of organic matter, such as in zones of pollution off Marseille, where it is present at high densities throughout the year. [3]
The tentacles of Cerianthus membranaceus do not retract, but the whole animal can retreat into its tube. As it does so, some of the tentacles grip the rim and pull the tube closed behind it, effectively making it disappear from view. The tube is normally a permanent home, but if the anemone is disturbed from below, as by a burrowing sea urchin, it can eject itself from its tube, move to a new location and secrete a new tube. [4]
Cerianthus membranaceus feeds on small fish and planktonic organisms which it catches with its tentacles. It is a protandrous hermaphrodite, starting life as a male and becoming a female later. The gametes are liberated into the sea and after fertilisation, the developing larvae drift with the plankton for a long time before settling on the seabed and undergoing metamorphosis into juvenile polyps. [2]
The tube is used as a refuge by many commensal organisms, especially polychaete worms and shrimps. The horseshoe worm, Phoronis australis , often attaches itself to the outside of the tube. [2] There may be twenty to fifty horseshoe worms associated with one tube anemone. [5]
The lifespan of C. membranaceus in the wild is not known, but some individuals have been occupants of a tank in Naples Aquarium for more than fifty years. [2]
Anthozoa is a class of marine invertebrates which includes the sea anemones, stony corals and soft corals. Adult anthozoans are almost all attached to the seabed, while their larvae can disperse as part of the plankton. The basic unit of the adult is the polyp; this consists of a cylindrical column topped by a disc with a central mouth surrounded by tentacles. Sea anemones are mostly solitary, but the majority of corals are colonial, being formed by the budding of new polyps from an original, founding individual. Colonies are strengthened by calcium carbonate and other materials and take various massive, plate-like, bushy or leafy forms.
Phoronis is one of the two genera of the horseshoe worm family (Phoronidae), in the phylum Phoronida. The body has two sections, each with its own coelom. There is a specialist feeding structure, the lophophore, which is an extension of the wall of the coelom and is surrounded by tentacles. The gut is U-shaped. The diagnostic feature that distinguishes this genus is the lack of epidermal invagination at the base of the lophophore. These worms are filter feeders. They live on hard substrates or soft sediments in marine environments throughout the world. They have different modes of reproduction which help with their success.
Tube-dwelling anemones or ceriantharians look very similar to sea anemones but belong to an entirely different class of anthozoans. They are solitary, living buried in soft sediments. Tube anemones live inside and can withdraw into tubes, which are composed of a fibrous material made from secreted mucus and threads of nematocyst-like organelles known as ptychocysts. Within the tubes of these ceriantharians, more than one polyp is present, which is an exceptional trait because species that create tube systems usually contain only one polyp per tube. Ceriantharians were formerly classified in the taxon Ceriantipatharia along with the black corals but have since been moved to their own class, Ceriantharia.
Sea anemones are a group of predatory marine invertebrates of the order Actiniaria. Because of their colourful appearance, they are named after the Anemone, a terrestrial flowering plant. Sea anemones are classified in the phylum Cnidaria, class Anthozoa, subclass Hexacorallia. As cnidarians, sea anemones are related to corals, jellyfish, tube-dwelling anemones, and Hydra. Unlike jellyfish, sea anemones do not have a medusa stage in their life cycle.
Phoronids are a small phylum of marine animals that filter-feed with a lophophore, and build upright tubes of chitin to support and protect their soft bodies. They live in most of the oceans and seas, including the Arctic Ocean but excluding the Antarctic Ocean, and between the intertidal zone and about 400 meters down. Most adult phoronids are 2 cm long and about 1.5 mm wide, although the largest are 50 cm long.
Hydroides norvegica is a species of tube-forming annelid worm in the family Serpulidae. It is found on submerged rocks, shells, piles and boats in many coastal areas around the world. It is the type species of the genus Hydroides.
Phoronis psammophila is a species of marine horseshoe worm in the phylum Phoronida. It lives in a tube projecting from the sea floor in shallow seas around the world.
Phoronopsis californica is a species of marine horseshoe worm in the phylum Phoronida. It was first described as a new species by William Hilton in 1930 when he found it at Balboa Bay in Newport Beach, California.
Cerianthus is a genus of tube-dwelling anemones in the family Cerianthidae. Members of the genus are found worldwide. They are predators, scavengers and omnivores.
Cerianthus lloydii is a species of tube-dwelling sea anemone in the family Cerianthidae. It is sometimes called the lesser cylinder anemone and is found in shallow seas around the coasts of north west Europe.
Bartholomea annulata is a species of sea anemone in the family Aiptasiidae, commonly known as the ringed anemone or corkscrew anemone. It is one of the most common anemones found on reefs in the Caribbean Sea.
Actinodendron arboreum, commonly known as tree anemone or hell's fire anemone, is a species of sea anemone in the family Actinodendronidae. It is native to the Indo-Pacific where it grows at depths of down to 28 metres (92 ft). Most sea anemone species are harmless to humans, but A. arboreum is highly venomous and its sting can cause severe skin ulcers.
Cerianthus filiformis is a species of tube-dwelling sea anemone in the family Cerianthidae. It is found throughout the tropical waters of the western Indo-Pacific Ocean.
Sabella spallanzanii is a species of marine polychaete worms in the family Sabellidae. Common names include the Mediterranean fanworm, the feather duster worm, the European fan worm and the pencil worm. It is native to shallow waters in the northeastern Atlantic Ocean and the Mediterranean Sea. It has spread to various other parts of the world and is included on the Global Invasive Species Database.
Phoronis australis is a species of marine horseshoe worm in the phylum Phoronida. It is found in shallow warm-temperate and tropical waters in the eastern Atlantic Ocean and the Indo-Pacific region and was first detected in the Mediterranean Sea in the late twentieth century. These worms live in association with tube-dwelling anemones, particularly those in the genus Cerianthus.
Phoronis ovalis is a species of marine horseshoe worm in the phylum Phoronida. It is found in shallow waters in the northeastern Atlantic Ocean, the southeastern Atlantic Ocean, Argentina, and other scattered locations worldwide. These worms secrete a tube into which they can retreat, and burrow into the shells of molluscs.
Ceriantheomorphe brasiliensis is a species of tube-dwelling anemones in the family Cerianthidae. It is found in the tropical western Atlantic Ocean, the Caribbean Sea and the Gulf of Mexico. It is currently listed as endangered based on a lack of evidence.
Ceriantheopsis americana is a species of tube-dwelling anemone in the family Cerianthidae. It is a burrowing species and lives in deep sand or muddy sand in a long slender tube that it creates.
Hydroides ezoensis is a species of tube-forming annelid worm in the family Serpulidae. It is native to the temperate northern Pacific and the central Indo-Pacific and is found in the intertidal zone and on submerged rocks, shells, pilings, jetties and boats.
Actinostella flosculifera, the collared sand anemone, is a species of sea anemone in the family Actiniidae. It is found semi-immersed in the sediment in shallow water in the tropical and subtropical Atlantic Ocean.