| Mesacmaea mitchellii | |
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| Mesacmaea mitchellii at the left top | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Cnidaria |
| Class: | Anthozoa |
| Order: | Actiniaria |
| Family: | Haloclavidae |
| Genus: | Mesacmaea |
| Species: | M. mitchellii |
| Binomial name | |
| Mesacmaea mitchellii | |
| Synonyms [1] | |
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Mesacmaea mitchellii is a species of sea anemone in the family Haloclavidae. It is found in the northeastern Atlantic Ocean and the Mediterranean Sea where it burrows in soft sediment.
This species was first described in 1853 by the British naturalist Philip Henry Gosse as Ilyanthus mitchellii. In 1881, the Italian zoologist Angelo Andres described a new species of sea anemone, Mesacmaea stellatus, and erecting the genus Mesacmaea to accommodate it. Since then, Mesacmaea stellatus has been synonymised with Ilyanthus mitchellii, the species becoming Mesacmaea mitchellii. Two other species from the genus Ilyanthus have also been transferred to the genus Mesacmaea. [2]
M. mitchellii is a robust and distinctive burrowing sea anemone. The column is pear-shaped with a rounded base, and is divided into a scapus, the main part of the column, and a scapulus, a smooth retractile region; the physa, or basal region, is able to adhere firmly to a hard surface but is not normally attached because the animal habitually burrows. The scapus often has sand grains sticking to it. The oral disc bears up to 36 tentacles in several cycles; the inner cycle contains seven tentacles which tend to be raised above the central mouth while the remaining tentacles are spread widely over the surface of the sediment. [3] The column can be up to 50 mm (2 in) across and 70 mm (2.8 in) including the extended tentacles. The scapus is generally reddish, orange or buff, the scapulus is grey, and the oral disc and tentacles are patterned in brown, cream and red. [3] Internally, the pharynx has a single siphonoglyph (ciliated groove) and the gastrovascular cavity is subdivided by complete mesenteries, no incomplete mesenteries being present. The retractor muscles are strong. [2]
Mesacmaea mitchellii is native to the northeastern Atlantic Ocean where it occurs in the sublittoral zone around the coasts of Britain and Western Europe and in the Mediterranean Sea. Its depth range is between 15 and 100 m (50 and 330 ft) and its habitat is soft sediment such as sand and gravel. The base of the column is used for burrowing, and the animal feeds with only the top of the column, oral disc and tentacles above the sediment. [4]
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.
Sea anemones are the marine, predatory animals of the order Actiniaria. They are named after the anemone, a terrestrial flowering plant, because of the colourful appearance of many. 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.
Sagartia troglodytes is a species of sea anemone in the family Sagartiidae, also known as the mud sagartia or the cave-dwelling anemone.
Haloclavidae is a family of sea anemones. Members of the family are found worldwide and many live largely buried in soft substrates with only their oral disc and tentacles protruding.
Peachia is a genus of sea anemone in the family Haloclavidae. Members of this genus typically burrow into soft substrates. The only part of the animal that is normally visible is the oral disc and tentacles which lie flat on the sand in a star shape. The type species is Peachia cylindrica.
Peachia cylindrica is a large species of sea anemone in the family Haloclavidae. It is normally found burrowed into soft substrates, the only visible part of the animal being the oral disc and tentacles which usually lie flat on the sand. It is the type species of the genus Peachia.
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.
Condylactis aurantiaca, commonly known as the golden anemone, is a species of sea anemone in the family Actiniidae. This species always remains largely buried in sand or sediment, attached to the substrate, with only the oral disc and tentacles visible.
Aulactinia verrucosa, the gem anemone, is a species of sea anemone in the family Actiniidae. It is found on rocky coasts in the northeastern Atlantic Ocean, North Sea and Mediterranean Sea.
Anthopleura thallia, commonly known as the glaucous pimplet, is a species of sea anemone in the family Actiniidae. It is found in shallow water in the northeastern Atlantic Ocean and the Mediterranean Sea.
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.
Actinothoe sphyrodeta, the sandalled anemone, is a small sea anemone in the family Sagartiidae. It is native to the northeastern Atlantic Ocean and is common on the north, west and south coasts of Britain. It is usually grey or whitish but may have an orange oral disc. The translucent white tentacles that grow around the edge of the oral disc can number up to 120.
Edwardsiella lineata, the lined anemone, is a species of sea anemone in the family Edwardsiidae. It is native to the northwestern Atlantic Ocean where it occurs in the subtidal zone.
Haloclava producta is a species of sea anemone in the family Haloclavidae, commonly known as the ghost anemone. This species is native to shallow water in the northwestern Atlantic Ocean, between Cape Hatteras and the Bay of Fundy, where it makes a temporary burrow in soft sediment. It is found on sand flats, both intertidally and subtidally.
Paranthus rapiformis, the onion anemone, is a species of sea anemone in the family Actinostolidae. It was first described by the French naturalist Charles Alexandre Lesueur in 1817 and is native to the northwestern Atlantic Ocean and the Gulf of Mexico.
Corynactis viridis, the jewel anemone, is a brightly coloured anthozoan similar in body form to a sea anemone or a scleractinian coral polyp, but in the order Corallimorpharia. It is found in the northeastern Atlantic Ocean and the Mediterranean Sea and was first described by the Irish naturalist George Allman in 1846.
Mesacmaea is a genus of sea anemone in the family Haloclavidae. Members of this genus typically burrow into soft substrates. The only part of the animal that is normally visible is the oral disc and tentacles which lie flat on the sand in a star shape.
Phascolosoma granulatum is a species of peanut worm in the family Phascolosomatidae. It is found in shallow water in the northeastern Atlantic Ocean and the Mediterranean Sea.
Edwardsia neozelanica, commonly known as the burrowing anemone, is a small cryptic sea anemone from New Zealand. It burrows into soft mud or sand, and when covered with water extends its tentacles to feed on tiny particles of detritus.
Isotealia antarctica, the salmon anemone, is a species of sea anemone in the family Actiniidae. It is found in the southern Atlantic and Pacific Oceans and the waters around Antarctica. It is a filter feeder and opportunistic predator.