| Velatida | |
|---|---|
 | |
| Pteraster capensis | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Class: | Asteroidea |
| Order: | Velatida Perrier, 1884 |
| Families | |
5, see text | |
The Velatida are an order of sea stars containing about 200 species in five families. These sea stars normally have thick bodies with large discs. [1]
This order contains mostly deep or cold seas sea stars, often with a wide distribution (sometimes global). They have a pentagonal or star shape, with between 5 and 15 arms. Their skeleton is weakly developed, which confers them a good flexibility, and numerous papillae on the aboral surface allow them to breathe in poorly oxygenated waters. Their pedicellariae are often provided with spines. The smallest are Caymanostellidae (between 0,5 and 3 cm) and the biggest Pterasteridae (up to 30 cm). [2]
New molecular evidence now suggests a relationship between some velatid and valvatid families.
List of families according to World Register of Marine Species: [3]
The Moraceae—often called the mulberry family or fig family—are a family of flowering plants comprising about 38 genera and over 1100 species. Most are widespread in tropical and subtropical regions, less so in temperate climates; however, their distribution is cosmopolitan overall. The only synapomorphy within the Moraceae is presence of laticifers and milky sap in all parenchymatous tissues, but generally useful field characters include two carpels sometimes with one reduced, compound inconspicuous flowers, and compound fruits. The family includes well-known plants such as the fig, banyan, breadfruit, jackfruit, mulberry, and Osage orange. The 'flowers' of Moraceae are often pseudanthia.
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 live 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.
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. They are found on the sea floor worldwide. The number of known holothurian species worldwide is about 1,786, 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.
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.
The Valvatida are an order of starfish in the class Asteroidea, which contains 695 species in 172 genera in 17 families.
Pāua is the Māori name given to three New Zealand species of large edible sea snails, marine gastropod molluscs which belong to the family Haliotidae, known in the United States and Australia as abalone, and in the United Kingdom as ormer shells. Pāua has entered English through common use in the New Zealand English dialect, and is both singular and plural, following the grammar rules of its original language.
The Asterinidae are a large family of sea stars in the order Valvatida.
The Buthidae are the largest family of scorpions, containing about 100 genera and 1339 species as of 2022. A few very large genera are known, but a high number of species-poor or monotypic ones also exist. New taxa are being described at a rate of several new species per year. They have a cosmopolitan distribution throughout tropical and subtropical environments worldwide. Together with four other families, the Buthidae make up the superfamily Buthoidea. The family was established by Carl Ludwig Koch in 1837.
The Gobiiformes are an order of fish that includes the gobies and their relatives. The order, which was previously considered a suborder of Perciformes, is made up of about 2,211 species that are divided between seven families. Phylogenetic relationships of the Gobiiformes have been elucidated using molecular data. Gobiiforms are primarily small species that live in marine water, but roughly 10% of these species inhabit fresh water. This order is composed chiefly of benthic or burrowing species; like many other benthic fishes, most gobiiforms do not have a gas bladder or any other means of controlling their buoyancy in water, so they must spend most of their time on or near the bottom. Gobiiformes means "goby-like".
Goniasteridae constitute the largest family of sea stars, included in the order Valvatida. They are mostly deep-dwelling species, but the family also include several colorful shallow tropical species.
The Forcipulatida are an order of sea stars, containing three families and 49 genera.
The Spinulosida are an order of sea stars containing at least 120 species in seven genera and one family.
The Brisingids are deep-sea-dwelling starfish in the order Brisingida.
Coastal fish, also called inshore fish or neritic fish, inhabit the sea between the shoreline and the edge of the continental shelf. Since the continental shelf is usually less than 200 metres (660 ft) deep, it follows that pelagic coastal fish are generally epipelagic fish, inhabiting the sunlit epipelagic zone. Coastal fish can be contrasted with oceanic fish or offshore fish, which inhabit the deep seas beyond the continental shelves.
Benthopectinidae is a family of sea stars containing at least 75 species in eight genera. It is the only family in the monotypic order Notomyotida.
Pteraster tesselatus, the slime star or cushion star, is a species of starfish in the family Pterasteridae found in the North Pacific.
Caymanostellidae is a family of sea stars containing six species in two families. These asteroids normally have thick bodies with large discs.
Myxasteridae is a family of deep-sea velatid sea stars containing nine species in three genera.
Euretaster insignis, commonly known as the striking sea star, is a species of starfish in the family Pterasteridae found in the central west Pacific Ocean. It is one of only three species in the order Velatida to be found in shallow water in the tropics. The young are brooded in a cavity underneath a "supradorsal" membrane.
Maureen Elizabeth Downey was an American zoologist who worked for three decades at the Smithsonian National Museum of Natural History. Known as "The Starfish Lady," she was an authority on sea stars and other echinoderms, co-founding the International Echinoderm Conference in 1972. Among her discoveries is Midgardia xandaros, the world's largest starfish.
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