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| Salenioida Temporal range: | |
|---|---|
 | |
| Salenia petalifera | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Echinodermata |
| Class: | Echinoidea |
| Subclass: | Euechinoidea |
| Infraclass: | Carinacea |
| Superorder: | Echinacea |
| Order: | Salenioida Delage, 1903 |
The Salenioida are an order of sea urchins.
They are distinguished from other sea urchins by the presence of a large plate on the upper surface, with the anus to one side. They have very large tubercles between the ambulacral plates, and much smaller ones on the ambulacral plates themselves.
According to World Register of Marine Species :
Sea urchins are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin are distributed on the seabeds of every ocean and inhabit every depth zone from the intertidal seashore down to 5,000 meters. The spherical, hard shells (tests) of sea urchins are round and covered in spines. Most urchin spines range in length from 3 to 10 cm, with outliers such as the black sea urchin possessing spines as long as 30 cm (12 in). Sea urchins move slowly, crawling with tube feet, and also propel themselves with their spines. Although algae are the primary diet, sea urchins also eat slow-moving (sessile) animals. Predators that eat sea urchins include a wide variety of fish, starfish, crabs, marine mammals, and humans.
The water vascular system is a hydraulic system used by echinoderms, such as sea stars and sea urchins, for locomotion, food and waste transportation, and respiration. The system is composed of canals connecting numerous tube feet. Echinoderms move by alternately contracting muscles that force water into the tube feet, causing them to extend and push against the ground, then relaxing to allow the feet to retract.
Echinus esculentus, the European edible sea urchin or common sea urchin, is a species of marine invertebrate in the Echinidae family. It is found in coastal areas of western Europe down to a depth of 1,200 m (3,900 ft). It is considered "Near threatened" in the IUCN Red List of Threatened Species.
Loxechinus albus is an echinoderm of the family Parechinidae, native to coastal southern South America, ranging from Ecuador, along the entire coasts of Peru and Chile, to Argentina, as well as the Falkland Islands. It is the only species in the genus Loxechinus. It is known as the Chilean sea urchin or red sea urchin, but the latter name is typically used for the North Pacific Mesocentrotus franciscanus and it is not the only species of sea urchin in Chile. L. albus is found on rocky reefs and shores in the intertidal and subtidal zones to a depth of 340 m (1,120 ft).
Hemicentrotus pulcherrimus is a species of sea urchin, the only one in the monotypic genus Hemicentrotus. It was first described by the American engineer and marine zoologist Alexander Agassiz in 1864 as Psammechinus pulcherrimus. Its range extends along the coasts of Korea and China, and in Japan from Kyūshū to Ishikari Bay. An edible species, it is harvested from Kyūshū to Fukui, in the Sea of Japan.
Cidaroida is an order of primitive sea urchins, the only living order of the subclass Perischoechinoidea. All other orders of this subclass, which were even more primitive than the living forms, became extinct during the Mesozoic.
Perischoechinoidea is a subclass of primitive sea urchins that were abundant in the Palaeozoic seas. However, the great majority of species died out during the Mesozoic, as the more advanced euechinoid sea urchins became common. Today, only a single order, the Cidaroida, survives.
Dendraster excentricus, also known as the eccentric sand dollar, sea-cake, biscuit-urchin, western sand dollar, or Pacific sand dollar, is a species of sand dollar in the family Dendrasteridae. It is a flattened, burrowing sea urchin found in the north-eastern Pacific Ocean from Alaska to Baja California.
The Parechinidae are a family of sea urchins in the class Echinoidea.
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.
The Camarodonta are an order of globular sea urchins in the class Echinoidea. The fossil record shows that camarodonts have been in existence since the Lower Cretaceous.
Echinidae is a family of sea urchins in the order Camarodonta. Members of the family are found in the Atlantic Ocean and the Antarctic.
Echinus melo, melon sea urchin, is a species of sea urchin in the family Echinidae.
Aspidodiadema jacobyi is a small sea urchin in the family Aspidodiadematidae. It lives in tropical seas at great depths. Aspidodiadema jacobyi was first scientifically described in 1880 by Alexander Emanuel Agassiz, an American scientist.
Asthenosoma varium is a sea urchin. Growing up to 25 cm (10 in) in diameter, it lives on sand and rubble sea bottoms in the Indo-Pacific, from the Red Sea to Australia and Southern Japan. Its venom tipped spines, with distinctive globular swellings below the tip, can inflict a painful sting if handled; the pain lasts as long as several hours. This capacity, perhaps coupled with its reddish-brown colour, has given it the common name fire urchin; other commonly used names are Pacific fire urchin, elusive sea urchin, variable fire urchin, and electric sea urchin.
Heterocentrotus is a genus of slate pencil urchins, part of the familia Echinometridae. They are mainly found in the Indo-Pacific basin, especially in Reunion or Hawaii. This genus appeared in the Miocene and spread throughout the warm Indo-Pacific.
Pelanechinus is an extinct genus of sea urchins in the order Echinothurioida. It is placed in the family Pelanechinidae and is in the stem group of echinoids.
Ossicles are small calcareous elements embedded in the dermis of the body wall of echinoderms. They form part of the endoskeleton and provide rigidity and protection. They are found in different forms and arrangements in sea urchins, starfish, brittle stars, sea cucumbers, and crinoids. The ossicles and spines are the only parts of the animal likely to be fossilized after an echinoderm dies.
Tetrapygus is a genus of sea urchins in the family Arbaciidae. It is a monotypic genus and the only species is Tetrapygus niger which was first described by the Chilean naturalist Juan Ignacio Molina in 1782. It is found in the southeastern Pacific Ocean on the coasts of South America.
Echinocyamus pusillus, commonly known as the pea urchin or green urchin, is a species of sand dollar, a sea urchin in the family Fibulariidae, native to the northeastern Atlantic Ocean and the Mediterranean Sea. It buries itself in gravel or coarse sand at depths down to about 1,250 m (4,000 ft).
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