| Marthasterias | |
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| Marthasterias glacialis | |
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| Genus: | Marthasterias Jullien, 1878 [1] |
| Species: | M. glacialis |
| Binomial name | |
| Marthasterias glacialis (Linnaeus, 1758) [2] | |
Marthasterias is a genus of starfish in the family Asteriidae. It is monotypic and the only species in the genus is Marthasterias glacialis, commonly known as the spiny starfish. It is native to the eastern Atlantic Ocean.
Marthasterias glacialis is a fairly large starfish with a small central disc and five slender, tapering arms. Each arm has three longitudinal rows of conical, whitish spines, usually with purple tips, each surrounded by a wreath of pedicellariae. The background colour is variable and may be brownish or greenish-grey, tinged with yellow or red and sometimes with purple at the tips of the arms. This species can grow to 70 cm (28 in) but a more usual size is 25 to 30 cm (10 to 12 in). It is sometimes confused with the northern starfish Leptasterias muelleri . [3]
Marthasterias glacialis is native to the Eastern Atlantic Ocean (from Iceland and Macaronesia in the North Atlantic to Angola and South Africa in the South Atlantic), and the Baltic and Mediterranean seas. [4] [5] Around the British Isles it is limited to the western side of Scotland, Wales, the western part of southern England and most of Ireland. Its depth range is subtidal down to about 200 m (656 ft) and it is found on both sheltered muddy substrates and on rocks. [3]
Like other starfish in the family Asteriidae, Marthasterias glacialis is a predator and feeds mostly on bivalve molluscs and other invertebrates. [6] It has been found that secondary metabolites known as saponins, found within the starfish's tissues, have a dramatic effect on the whelk Buccinum undatum . At low concentrations they cause the mollusc to withdraw from the vicinity of the starfish and at higher concentrations they cause convulsions in the mollusc's musculature. [7] The sea urchins Strongylocentrotus droebachiensis and Psammechinus miliaris are also affected by the chemicals. S. droebachiensis flees but P. miliaris has toxic pedicellariae and is able to defend itself. [8]
The reproductive biology of this starfish has been little studied but off the coast of Ireland, individuals gather together in very shallow water in July and August. A few days later, on a warm afternoon, they have been observed to arch their bodies and release spawn into the sea. A rise in the water temperature seems to have triggered the spawning. Male starfish as small as 2.5 cm (1 in) were observed to spawn, and females of at least 9 cm (3.5 in) diameter. [5]
Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea. Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or basket stars. Starfish are also known as asteroids due to being in the class Asteroidea. About 1,900 species of starfish occur on the seabed in all the world's oceans, from warm, tropical zones to frigid, polar regions. They are found from the intertidal zone down to abyssal depths, at 6,000 m (20,000 ft) below the surface.
Asterias is a genus of the Asteriidae family of sea stars. It includes several of the best-known species of sea stars, including the (Atlantic) common starfish, Asterias rubens, and the northern Pacific seastar, Asterias amurensis. The genus contains a total of eight species in all. All species have five arms and are native to shallow oceanic areas of cold to temperate parts of the Holarctic. These starfish have planktonic larvae. Asterias amurensis is an invasive species in Australia and can in some years become a pest in the Japanese mariculture industry.
The Asteriidae are a diverse family of Asteroidea in the order Forcipulatida. It is one of three families in the order Forcipulatida.
Buccinum undatum, the common whelk or the waved buccinum, is a large, edible marine gastropod in the family Buccinidae, the "true whelks".
Astropecten aranciacus, the red comb star, is a sea star of the family Astropectinidae. It is native to the east Atlantic Ocean and Mediterranean Sea.
The common starfish, common sea star or sugar starfish is the most common and familiar starfish in the north-east Atlantic. Belonging to the family Asteriidae, it has five arms and usually grows to between 10–30 cm across, although larger specimens are known. The common starfish is usually orange or brownish in color, and sometimes violet; specimens found in deeper waters are pale. The common starfish is found on rocky and gravelly substrates where it feeds on mollusks and other benthic invertebrates.
In 1758, in the 10th edition of Systema Naturae, the Swedish scientist and taxonomist Carl Linnaeus described the class "Vermes" as:
Animals of slow motion, soft substance, able to increase their bulk and restore parts which have been destroyed, extremely tenacious of life, and the inhabitants of moist places. Many of them are without a distinct head, and most of them without feet. They are principally distinguished by their tentacles. By the Ancients they were not improperly called imperfect animals, as being destitute of ears, nose, head, eyes and legs; and are therefore totally distinct from Insects.
Novocrania anomala is a species of brachiopod found offshore in the eastern Atlantic Ocean.
Psammechinus miliaris is a species of sea urchin in the family Parechinidae. It is sometimes known as the green sea urchin or shore sea urchin. It is found in shallow areas of the eastern Atlantic Ocean and the North Sea.
Echinidae is a family of sea urchins in the order Echinoida. Members of the family are found in the Atlantic Ocean and the Antarctic.
Serpula vermicularis, known by common names including the calcareous tubeworm, fan worm, plume worm or red tube worm, is a species of segmented marine polychaete worm in the family Serpulidae. It is the type species of the genus Serpula and was first described by Carl Linnaeus in his 1767 12th edition of Systema Naturae. It lives in a tube into which it can retract.
The purple sunstar, northern sunstar, or smooth sun star, Solaster endeca, is a species of starfish in the family Solasteridae.
Asterias forbesi, commonly known as Forbes sea star, is a species of starfish in the family Asteriidae. It is found in shallow waters in the northwest Atlantic Ocean and the Caribbean Sea.
Evasterias troschelii is a species of starfish in the family Asteriidae. Its common names include the mottled star, false ochre sea star and Troschel's true star. It is found in Kamchatka and the north western coast of North America.
Diploria is a monotypic genus of massive reef building stony corals in the family Mussidae. It is represented by a single species, Diploria labyrinthiformis, commonly known as grooved brain coral and is found in the western Atlantic Ocean and Caribbean Sea. It has a familiar, maze-like appearance.
Stylasterias is a genus of starfish in the family Asteriidae. Stylasterias forreri, the velcro star, is the only species in the genus. It is found on the Pacific coast of Canada and the United States.
Leptasterias polaris, the polar six-rayed star, is a species of starfish in the family Asteriidae. It is found in cold waters in the northwest Atlantic Ocean and in polar regions.
Leptasterias muelleri, the northern starfish, is a species of starfish in the family Asteriidae. It is found in the Arctic Ocean and the northern Atlantic Ocean. It is a predator and scavenger and is unusual among starfish in that it broods its young.
Novodinia antillensis, the velcro sea star, is a species of starfish in the family Brisingidae. It is found in the deep sea in the tropical and subtropical western Atlantic Ocean, being quite common at a depth of around 500 m (1,640 ft) on the Mesoamerican Reef off Roatán, Honduras.