| Diplasterias brucei | |
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| Species: | D. brucei |
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| Diplasterias brucei (Koehler, 1908) [1] | |
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Diplasterias brucei is a species of starfish in the family Asteriidae. [1] It is found in the Pacific Ocean and Southern Ocean. It is a predator and scavenger and is unusual among starfish in that it broods its young. [2]
D. brucei usually has five arms, but in the vicinity of South Georgia, a six-armed form is common. This starfish varies in colour from a pale bluish-green to a yellowish or orange hue. The maximum size is about 25 cm (10 in) across. [3]
D. brucei is found in the Pacific Ocean and Southern Ocean. In Antarctica, the species is found on the seabed in the Antarctic Peninsula and in East Antarctica, at depths down to about 725 m (2,400 ft). [3]
D. brucei is one of the more conspicuous animals in the zone deeper than 33 m (110 ft) which is the lower limit for anchor ice formation. This zone is characterised by a layer of sponge spicules and dead mollusc shells a metre or more thick, swathed in living sponges. This matrix is a biodiverse environment rich in sea anemones, polychaete worms, hydroids, bryozoans and molluscs. The bivalve mollusc Limatula hodgsoni is particularly common and there are also great quantities of tiny gastropod molluscs in the genera Onoba and Margarella . [4]
The starfishes Acodontaster conspicuus , Acodontaster hodgsoni , Odontaster meridionalis and Perknaster fuscus feed on the sponges, while Odontaster validus mostly scavenges, and D. brucei and the gastropod Trophonella longstaffi both feed on the bivalve L. hodgsoni. [4] D. brucei primarily feeds on molluscs, but does not seem to eat sponges as do many other starfish. It is sometimes preyed on by the sea anemone Urticinopsis antarctica . Developing embryos of this species are brooded by the female until they have developed into juvenile starfish. [3]
The starfish O. validus is an omnivorous predator and scavenger in Antarctic waters, a keystone species feeding on almost anything organic with which it comes in contact, including other species of starfish. [5] However, O validus avoids the brooded embryos of D. brucei, which contain secondary metabolites which act as a deterrent. This is of importance in a species that takes a long time to develop in the cold waters which it inhabits. [2]
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 1,500 species of starfish occur on the seabed in all the world's oceans, from the tropics to frigid polar waters. They are found from the intertidal zone down to abyssal depths, 6,000 m (20,000 ft) below the surface.
The Echinasteridae are a family of starfish in the monotypic order Spinulosida. The family includes eight genera and about 133 species found on the seabed in various habitats around the world.
Nacella macquariensis is a species of true limpet, a marine gastropod mollusc in the family Nacellidae. It is found on the lower foreshore and in the shallow sub-littoral zone of certain islands in the southern Indian Ocean and Southern Ocean.
Marine invertebrates are the invertebrates that live in marine habitats. Invertebrate is a blanket term that includes all animals apart from the vertebrate members of the chordate phylum. Invertebrates lack a vertebral column, and some have evolved a shell or a hard exoskeleton. As on land and in the air, marine invertebrates have a large variety of body plans, and have been categorised into over 30 phyla. They make up most of the macroscopic life in the oceans.
Parborlasia corrugatus is a proboscis worm in the family Cerebratulidae. This species of proboscis or ribbon worm can grow to 2 metres in length, and lives in marine environments down to 3,590 metres (11,780 ft). This scavenger and predator is widely distributed in cold southern oceans.
Odontaster validus is a species of sea star in the family Odontasteridae. Its range includes the Southern Ocean and the seas around the mainland and islands of Antarctica.
Acodontaster is a genus of starfish in the family Odontasteridae. Members of the genus are found in the Southern Ocean, in the waters off Antarctica and the island groups nearby. Acodontaster elongatus is additionally found further north in the Atlantic Ocean on the eastern seaboard of South America.
Acodontaster conspicuus is a species of starfish in the family Odontasteridae. It is found in the Southern Ocean, in the waters off Antarctica and the island groups nearby.
Adamussium is a monotypic genus of bivalve molluscs in the large family of scallops, the Pectinidae. The Antarctic scallop is the only species in the genus though its exact relationship to other members of the family is unclear. It is found in the ice-cold seas surrounding Antarctica, sometimes at great depths.
Sterechinus neumayeri, the Antarctic sea urchin, is a species of sea urchin in the family Echinidae. It is found living on the seabed in the waters around Antarctica. It has been used as a model organism in the fields of reproductive biology, embryology, ecology, physiology and toxicology.
Homaxinella balfourensis is a species of sea sponge in the family Suberitidae. It is found in the seas around Antarctica and can grow in two forms, either branching out in one plane like a fan or forming an upright club-like structure.
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.
The wildlife of Antarctica are extremophiles, having to adapt to the dryness, low temperatures, and high exposure common in Antarctica. The extreme weather of the interior contrasts to the relatively mild conditions on the Antarctic Peninsula and the subantarctic islands, which have warmer temperatures and more liquid water. Much of the ocean around the mainland is covered by sea ice. The oceans themselves are a more stable environment for life, both in the water column and on the seabed.
Urticinopsis antarctica is a species of sea anemone in the family Actiniidae. It is found in the Southern Ocean around Antarctica.
Limatula hodgsoni is a species of bivalve mollusc in the family Limidae, the file shells or file clams. It is native to the seas around Antarctica.
Allantactis is a monotypic genus of sea anemones, and Allantactis parasitica is the only species in the genus. This sea anemone lives at bathyal depths in the North Atlantic Ocean and has a symbiotic relationship with a gastropod mollusc.
Anasterias antarctica, commonly called the Cinderella starfish, is a species of starfish in the family Asteriidae. It is found in coastal waters in the Southern Ocean and around Antarctica.
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.
Tritoniella is a genus of sea slugs, specifically dendronotid nudibranchs. It is a marine gastropod mollusc in the family Tritoniidae. A monotypic genus, the only species is Tritoniella belli. The genus and species were both described in 1907 by the British diplomat and malacologist Charles Eliot.
Clavularia frankliniana is a species of colonial soft coral in the family Clavulariidae. It is found in the southern Atlantic Ocean and the waters around Antarctica. It was first described in 1902 by the French zoologist Louis Roule.