An echinoderm is any member of the phylum Echinodermata. The adults are recognisable by their radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the sea lilies or "stone lilies". Adult echinoderms are found on the sea bed at every ocean depth, from the intertidal zone to the abyssal zone. The phylum contains about 7,000 living species, making it the second-largest grouping of deuterostomes, after the chordates. Echinoderms are the largest entirely marine phylum. The first definitive echinoderms appeared near the start of the Cambrian.
Sea cucumbers are echinoderms from the class Holothuroidea. They are marine animals with a leathery skin and an elongated body containing a single, branched gonad. Sea cucumbers are found on the sea floor worldwide. The number of known holothurian species worldwide is about 1,717, with the greatest number being in the Asia-Pacific region. Many of these are gathered for human consumption and some species are cultivated in aquaculture systems. The harvested product is variously referred to as trepang, namako, bêche-de-mer, or balate. Sea cucumbers serve a useful role in the marine ecosystem as they help recycle nutrients, breaking down detritus and other organic matter, after which bacteria can continue the decomposition process.
The crown-of-thorns starfish, Acanthaster planci, is a large starfish that preys upon hard, or stony, coral polyps (Scleractinia). The crown-of-thorns starfish receives its name from venomous thorn-like spines that cover its upper surface, resembling the biblical crown of thorns. It is one of the largest starfish in the world.
Sea cucumbers are marine animals of the class Holothuroidea. They can be used as food, in fresh or dried form, in various cuisines. In some cultural contexts the sea cucumber is thought to have medicinal value.
The orange-footed sea cucumber is the largest sea cucumber in New England, United States. It is one of the most abundant and widespread species of holothurians within the North Atlantic Ocean and the Barents Sea (Russia), being most abundant along the eastern coast of North America.
Acanthaster is a bitypic genus of large and venomous starfish placed in its own family, Acanthasteridae. Its two members are known as crown-of-thorns starfish. Acanthaster are native to coral reefs in Indo-Pacific region.
Asterina is a genus of asteroideans in the family Asterinidae.
Holothuria mexicana, the donkey dung sea cucumber, is commonly found in the Caribbean and the Azores. It is a commercially important aspidochirote sea cucumber that can reach a total length of 50 cm (20 in).
Holothuria scabra, or sandfish, is a species of sea cucumber in the family Holothuriidae. It was placed in the subgenus Metriatyla by Rowe in 1969 and is the type species of the subgenus. Sandfish are harvested and processed into "beche-de-mer" and eaten in China and other Pacific coastal communities.
Sea cucumber stocks have been overexploited in the wild, resulting in incentives to grow them by aquaculture. Aquaculture means the sea cucumbers are farmed in contained areas where they can be cultured in a controlled manner. In China, sea cucumbers are cultured, along with prawns and some fish species, in integrated multi-trophic systems. In these systems, the sea cucumbers feed on the waste and feces from the other species. In this manner, what would otherwise be polluting byproducts from the culture of the other species become a valuable resource that is turned into a marketable product.
Aquilonastra conandae is a species of starfish from the family Asterinidae found near the Mascarene Islands in the Indian Ocean. It is known for its asexual reproduction and is fissiparous. It is a small starfish, discrete and camouflaged, and occurs in coral reefs in the surf zone of large waves. The species was described in 2006 by Australian marine biologists P. Mark O'Loughlin and Francis Winston Edric Rowe, and gets its name from Chantal Conand.
Aquilonastra chantalae is a species of starfish from the family Asterinidae. Asterinid sea stars are typically quite small with an often pentagonal-shaped body, though there are exceptions. They are dorsally flattened and have short arms. The body's thin periphery is built up by very small marginal plates. One distinct characteristic of those in this family is the presence of an aboral face shaped by crescent-like plates.
Aquilonastra is a genus of small sea stars within the family Asterinidae. It has over 20 described species.
Aquilonastra burtoni is a species of small sea star from the family Asterinidae from the Red Sea which has colonised the eastern Mediterranean by Lessepsian migration through the Suez Canal, although the Mediterranean populations are clonal reproducing through fissiparous asexual reproduction. It was originally described in 1840 by the English zoologist and philatelist John Edward Gray.
Thelenota rubralineata is a species of sea cucumber in the family Stichopodidae, in the phylum Echinodermata, mainly located in the central Indo-Pacific region. It has a distinctive coloring pattern, and can be found on the seabed near coral. T. rubralineata is part of the Thelenota genus, characterized by their large size and the presence of a calcareous ring.
Holothuria grisea, the gray sea cucumber, is a mid-sized coastal species of sea cucumber found in shallow tropical waters of the Atlantic Ocean from Florida to Southern Brazil and West Africa. They have a variety in color and can range from red to more yellowish with brown markings. They are also a food source for local and international markets with the majority of harvesting taking place in Brazil. This species is currently not over-fished and is not endangered or threatened.
Holothuria arguinensis is a species of sea cucumber in the family Holothuriidae and subgenus Roweothuria. It is found in waters off the northeast Atlantic Ocean and Mediterranean Sea. According to some scholarly research, the species is actively expanding its range and colonizing the south-eastern coast of Spain.
Holothuria (Platyperona) difficilis is a species of sea cucumber in the family Holothuriidae. Holothuria comes from Latin but is originally taken from Greek. Its meaning is a plantlike animal whose origin is uncertain.
