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Echinoid
Sea urchins () are spine (zoology), spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (Test (biology), tests) of sea urchins are round and spiny, ranging in diameter from . 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 (Sessility (motility), sessile) animals. Predation, Predators that eat sea urchins include a wide variety of fish, starfish, crabs, marine mammals. Sea urchins are also used as food especially in Japan. Adult sea urchins have fivefold symmetry, but their pluteus larvae feature Bilateral symmetry, bilateral (mirror) symmetry, indicating that the sea urchin belongs to the Bilateria group of animal phylum, phyla, which also comprises the chordates and the arthropods, the annelids and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perischoechinoidea
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. Most fossil forms had multiple columns of ambulacral plates, rather than the two rows found in all living species of sea urchin. They also lacked a perignathic girdle around the mouth. Taxonomy The group is probably a paraphyletic assemblage of stem forms, united only by their lack of more advanced features, rather than a true taxonomic clade. Subclass Perischoechinoidea * Order Cidaroida 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. Description ... * Order Bothriocidaroida † * Order Echinocystitoida † * Or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euechinoidea
The subclass Euechinoidea includes almost all living species of sea urchin, and fossil forms going back as far as the Triassic. Taxonomy List of orders according to World Register of Marine Species : * Infra-classis '' Acroechinoidea'' ** Order '' Aspidodiadematoida'' ** Order '' Diadematoida'' ** Order '' Micropygoida'' ** Order ''Pedinoida'' * Infra-classis ''Carinacea'' ** Super-order '' Calycina'' *** Order '' Phymosomatoida'' † *** Order ''Salenioida'' ** Super-order ''Echinacea'' *** Order ''Arbacioida'' *** Order '' Camarodonta'' *** Order '' Stomopneustoida'' * Order ''Echinothurioida'' * Infra-classis ''Irregularia'' ** Super-order ''Atelostomata'' *** Order ''Holasteroida'' *** Order ''Spatangoida'' ** Order '' Echinoneoida'' ** Order ''Holectypoida'' † ** Super-order ''Neognathostomata'' *** Order ''Cassiduloida'' *** Order ''Clypeasteroida'' *** Order '' Echinolampadoida'' *** Order '' Nucleolitidae'' † File:Spatangus purpureus rob.jpg , '' Spatangus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pedinoida
Pedinoida is an order of sea urchins, containing the single living genus ''Caenopedina''. The group was much more diverse during the Mesozoic, and represents the oldest surviving order of euechinoid sea urchins. They are distinguished from other sea urchins by the presence of a rigid test with tessellated plates. While their primary spines are solid, the smaller ones may be hollow, further distinguishing them from the closely related orders Diadematoida and Echinothurioida The Echinothurioida are an order of sea urchins in the class Echinoidea. Echinothurioids are distinguished from other sea urchins by the combination of a flexible test and hollow spines. The membrane around the mouth contains only simple plat ..., which possess only hollow spines. References * * Extant Early Triassic first appearances {{echinoidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clypeasteroida
Sand dollars (also known as a sea cookie or snapper biscuit in New Zealand, or pansy shell in South Africa) are species of flat, burrowing sea urchins belonging to the order Clypeasteroida. Some species within the order, not quite as flat, are known as '' sea biscuits''. Sand dollars can also be called "sand cakes" or "cake urchins". Anatomy Sand dollars are small in size, averaging from three to four inches. As with all members of the order Clypeasteroida, they possess a rigid skeleton called a test. The test consists of calcium carbonate plates arranged in a fivefold symmetric pattern. The test of certain species of sand dollar have slits called lunules that can help the animal stay embedded in the sand to stop it from being swept away by an ocean wave. In living individuals, the test is covered by a skin of velvet-textured spines which are covered with very small hairs (cilia). Coordinated movements of the spines enable sand dollars to move across the seabed. The velvety ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cidaroida
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. Description Their primary spines are much more widely separated than in other sea urchins, and they have no buccal slits. Other primitive features include relatively simple plates in the test, and the ambulacral plates continuing as a series across the membrane that surrounds the mouth. Families According to World Register of Marine Species: * family Anisocidaridae Vadet, 1999 † * super-family Cidaridea Gray, 1825 ** family Cidaridae Gray, 1825 ** family Ctenocidaridae Mortensen, 1928a ** family Paurocidaridae Vadet, 1999a † * family Diplocidaridae Gregory, 1900 † * family Heterocidaridae Mortensen, 1934 † * super-family Histocidaroidea Lambert, 1900 ** family Histocidaridae Lambert, 1900 ** family Psychocidaridae Ikeda, 1936 * famil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holectypoida
The Holectypoida are an order of sea urchins related to the sand dollars. The order consists of just two living genera, but was once more diverse. Description and characteristics In appearance, the living holectypoids are similar to sand dollars, but with less flattened bodies and an oval outline. They also lack the petal-like patterns found on the bodies of sand dollars. Taxonomy According to World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialis ... : * family Anorthopygidae Wagner & Durham, 1966b † * family Coenholectypidae Smith & Wright, 1999 † * family Discoididae Lambert, 1900 * family Holectypidae Lambert, 1900 † References * Gnathostomata (echinoid) Extant Early Jurassic first appearances {{echinoidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cassiduloida
Cassiduloida is an order (biology), order of sea urchins. The group was extremely diverse with many families and species during the Mesozoic, but today, only seven extant species remain. A 2019 phylogenetic systematics study by Souto et al. presented a revised classification of the cassiduloids, and hypothesised that the order probably originated in the Early Cretaceous. Description and characteristics Cassiduloids have a rounded or slightly oval appearance, and look somewhat similar to heart urchins, although they are actually more closely related to the sand dollars. They are distinguished from other sea urchins by the presence of smaller intervening areas between the main ambulacral areas on the oral surface. They have no lantern as adults, and the petaloids are poorly developed or absent. List of families and genera * family Cassidulidae (L. Agassiz and Desor, 1847) ** genus Cassidulus (Lamarck, 1801) ** genus Paralampas (Duncan & Sladen, 1882) ** genus Rhyncholampas (Ag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echinothurioida
The Echinothurioida are an order of sea urchins in the class Echinoidea. Echinothurioids are distinguished from other sea urchins by the combination of a flexible test and hollow spines. The membrane around the mouth contains only simple plates, in contrast to the more complex mouth parts of their close relatives, the Diadematoida. They are nearly all deepsea dwellers. Characteristics Echinothurioids have regular tests (shells) with 10 columns of plates. These plates are fused in groups of three with a central primary plate and a half plate on either side. The edge of each group of plates overlaps the next one in the manner of tiles on a roof and this means the test is flexible. These animals usually collapse to a disc shape when brought to the surface. The primary tubercles which articulate with the spines are each perforated by a hole and the spines are hollow. The primary spines are usually long and are used to support the test and in locomotion. In many species, the seconda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gnathostomata (echinoid)
The Gnathostomata are a superorder of sea urchins, including the familiar sand dollar Sand dollars (also known as a sea cookie or snapper biscuit in New Zealand, or pansy shell in South Africa) are species of flat, burrowing sea urchins belonging to the order Clypeasteroida. Some species within the order, not quite as flat, are k ...s. Gnathostomatans are irregular in shape, but unlike other irregular sea urchins, possess a feeding lantern. The mouth is located in the centre of the lower surface, as it is in most other sea urchins, but the anus is found to one side of the upper surface, rather than being central. The members of the group are adapted for burrowing in soft-bottomed marine environments. References * Echinoidea Extant Early Jurassic first appearances Animal superorders {{echinoidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echinacea (animal)
The Echinacea are a superorder of sea urchins. They are distinguished by the presence of a rigid test, with ten buccal plates around the mouth, and solid spines. Unlike some other sea urchins, they also possess gills. The group is a large one, with species found worldwide. Echinacea are part of Animalia (kingdom), Echinodermata (phylum), Echinozoa (subphylum), Echinoidea (class), Euechinoidea (subclass), Carinacea (infraclass). Child taxa According to World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialis ...: * Order Arbacioida (Gregory, 1900) -- 1 family and 2 fossiles * Order Camarodonta (Jackson, 1912) ** Infraorder Echinidea (Kroh & Smith, 2010) -- 5 families ** Infraorder Temnopleuridea (Kroh & Smith, 2010) -- 2 families and 2 fossiles * Orde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temnopleuroida
Temnopleuridea is an infraorder of sea urchins in the order Camarodonta. They are distinguished from other sea urchins by the presence of large fused plates on top of the feeding lantern. The test is usually sculpted to some degree, and has perforated tubercles. Taxonomy According to World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialis ...: * Family Glyphocyphidae Duncan, 1889 † * Family Temnopleuridae A. Agassiz, 1872 * Family Trigonocidaridae Mortensen, 1903b * Family Zeuglopleuridae Lewis, 1986 † Bibliography * * References Extant Late Cretaceous first appearances {{echinoidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salenioida
The Salenioida are an order of sea urchins. Description and characteristics 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. Taxonomy According to World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialist ... : * family Saleniidae L. Agassiz, 1838 * family Acrosaleniidae Gregory, 1900 † * family Goniophoridae Smith & Wright, 1990 † * family Hyposaleniidae Mortensen, 1934 † * family Pseudosaleniidae Vadet, 1999b † References * * Echinacea (animals) Echinoderm orders Extant Middle Jurassic first appearances {{echinoidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
