Acrocnida brachiata | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Echinodermata |
Class: | Ophiuroidea |
Order: | Ophiurida |
Family: | Amphiuridae |
Genus: | Acrocnida |
Species: | A. brachiata |
Binomial name | |
Acrocnida brachiata | |
Synonyms [1] | |
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Acrocnida brachiata, the sand burrowing brittlestar, is a species of brittle star in the family Amphiuridae. [2] It occurs on the seabed in the northeastern Atlantic Ocean and the North Sea, living semi-buried in the sand with only its arm tips projecting.
Acrocnida brachiata has a flat disc up to 12 mm (0.5 in) in diameter and five slender, clearly-demarcated, articulated arms up to 180 mm (7 in) in length. It is greyish-brown in colour. It can be distinguished from other similar species by the transverse furrows in the plates at the bases of the arms, the ventral scales bearing small tubercles and by the presence of an outer mouth papilla which is quite distinct from the paired papillae inside the mouth. The arms, which like other brittle stars flex sideways rather than up and down, have a pair of tentacle scales on each joint as well as numerous spines. [2]
Acrocnida brachiata occurs in the northeastern Atlantic Ocean and North Sea. It is common round the coasts of the British Isles where its depth range is from the lower shore down to about 40 m (130 ft). It is a benthic species, living on sandy bottoms and burying itself in the sediment, with only the tips of its arms projecting. [2] It often occurs in association with the burrowing sea urchin Echinocardium cordatum , [2] commonly known as the sea potato. [3]
There is a marked difference in morphology between populations in the intertidal zone and those thought to be the same species living in the subtidal zone. Study of these differences led to the describing of a new species Acrocnida spatulispina by Sabine Stöhr and Delphine Muths in 2009, for the deeper water individuals. The brittle stars in the genus Acrocnida show morphological affinities with Amphiura chiajei , but less with Amphiura filiformis . [4]
Brittle stars, serpent stars, or ophiuroids are echinoderms in the class Ophiuroidea, closely related to starfish. They crawl across the sea floor using their flexible arms for locomotion. The ophiuroids generally have five long, slender, whip-like arms which may reach up to 60 cm (24 in) in length on the largest specimens.
Amphiuridae are a large family of brittle stars of the suborder Gnathophiurina. Some species are used to study echinoderm development and bioluminescence.
Bathyporeia elegans is a species of amphipod crustacean in the genus Bathyporeia which occurs in the northeastern Atlantic Ocean. It is unpigmented, and grows up to 6 millimetres (0.24 in) long.
Ophiothrix fragilis is a species of brittle star in the order Ophiurida. It is found around the coasts of western Europe and is known in Britain as the common brittle star. It is also found along the coast of South Africa where it is known as the hairy brittle star.
Echinocardium cordatum, also known as the common heart urchin or the sea potato, is a sea urchin in the family Loveniidae. It is found in sub-tidal regions in temperate seas throughout the world. It lives buried in the sandy sea floor.
Ensis ensis, or the sword razor, is a razor clam, a marine bivalve mollusc in the family Pharidae. It lives buried in the sand and is found off the coasts of northwest Europe.
Fabulina fabula, the bean-like tellin, is a species of marine bivalve mollusc in the family Tellinidae. It is found off the coasts of northwest Europe, where it lives buried in sandy sediments.
Tellimya ferruginosa is a species of small marine bivalve mollusc in the family Lasaeidae. It is found on the eastern side of the Atlantic Ocean.
Ophiocomina nigra, commonly known as the black brittle star or black serpent star, is a species of marine invertebrate in the order Ophiurida. It occurs in the north-eastern Atlantic Ocean, the North Sea, and the Mediterranean Sea.
Ophiura albida is a species of brittle star in the order Ophiurida. It is typically found on the seabed in the north eastern Atlantic Ocean and in the Mediterranean Sea and is sometimes known as the serpent's table brittle star.
Amphiura filiformis is a species of brittle star belonging to the family Amphiuridae. It is found on the seabed in the north east Atlantic Ocean and adjoining seas to a depth of 200 metres (660 ft). It digs itself a shallow burrow in the sand and waves its arms in the water above to suspension feed on plankton.
Amphiura chiajei is a species of brittle star belonging to the family Amphiuridae. It is found in the northeastern Atlantic Ocean and adjoining seas to a depth of 1,000 metres (3,300 ft). It digs itself into the soft sediment of the seabed and raises its arms into the water above to suspension feed on plankton. It was first described by the British naturalist Edward Forbes in 1843, and was named for the Italian zoologist Stefano Delle Chiaje (1794–1860).
Ophiocoma echinata, the spiny ophiocoma, is a species of brittle star belonging to the family Ophiocomidae. It is the type species of the genus Ophiocoma and is found in the tropical west Atlantic Ocean, the Caribbean Sea and the Gulf of Mexico.
Ophiactis savignyi is a species of brittle star in the family Ophiactidae, commonly known as Savigny's brittle star or the little brittle star. It occurs in the tropical and subtropical parts of all the world's oceans and is thought to be the brittle star with the most widespread distribution. It was first described by the German zoologists Johannes Peter Müller and Franz Hermann Troschel in 1842. The specific name honours the French zoologist Marie Jules César Savigny.
Ophiopholis aculeata, the crevice brittle star or daisy brittle star, is a species of brittle star in the family Ophiactidae. It has a circum-polar distribution and is found in the Arctic Ocean, the northern Atlantic Ocean and the northern Pacific.
Acrocnida is a genus of brittle stars in the family Amphiuridae. The genus contains three members: Acrocnida brachiata, Acrocnida semisquamata, and Acrocnida spatulispina. There has also been observed hybridization between both Acrocnida brachiata and Acrocnida spatulispina. It is a fairly common genus, usually found along the coasts of Northwestern Europe, but with some species like semisquamata appearing around West Africa. Members of this genus primarily prefer intertidal and sub-tidal habitats, and they are they are less likely to be found in intertidal areas by comparison. This genus was not officially classified until 1926, by T. Gislén. One study found that due to the increased calcification that Acrocnida brachiata causes could be a potential source of Carbon Dioxide for not only the warm, shallow environments they live in, but also for the atmosphere.
Amphiodia urtica, commonly known as the burrowing brittle star or the long arm brittle star, is a species of brittle star belonging to the family Amphiuridae. It is found on the Pacific coast of North America at depths down to about 370 m (1,200 ft).
Abra prismatica is a species of bivalve mollusc in the family Semelidae. It occurs in the northeastern Atlantic Ocean, the North Sea and the Mediterranean Sea, where it lives on the seabed, in shallow areas buried in soft sediment.