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Echinoids
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] |
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] |
Echinoderm
An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) 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. The echinoderms are important both ecologically and geologically. Ecologically, there are few other groupings so abundant in the biotic desert of the deep sea, as well as shallower oceans. Most echinoderms are able to reproduce asexually and regenerate tissue, organs, and limbs; in some cases, they can undergo complete regeneration from a single limb. ... [...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] |
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] |
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] |
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] |
Tripneustes Ventricosus
''Tripneustes ventricosus'', commonly called the West Indian sea egg or white sea urchin, is a species of sea urchin. It is common in the Caribbean Sea, the Bahamas and Florida and may be found at depths of less than . Description The test of the West Indian sea egg is dark in color, usually black, dark purple or reddish brown, with white spines long. The test can reach in diameter. It is often covered with pieces of seagrass, fragments of shell and other debris in a manner similar to the closely related ''Tripneustes gratilla''.Humann, Paul, ''Reef Creature Identification'', Edited by Ned Deloach. New World Publications, Inc., 1992, p. 292-293. These decorations are held in place by tube feet among the spines and are believed to provide protection from the intense sunlight that penetrates the shallow water. Distribution and habitat The West Indian sea egg is found in shallow parts of the western Atlantic Ocean, the Caribbean Sea and Gulf of Mexico. Its range extends from Berm ... [...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] |
Spine (zoology)
In a zoological context, spines are hard, needle-like anatomical structures found in both vertebrate and invertebrate species. The spines of most spiny mammals are modified hairs, with a spongy center covered in a thick, hard layer of keratin and a sharp, sometimes barbed tip. Occurrence Mammals Spines in mammals include the prickles of hedgehogs and among rodents, the quills of both New World and Old World porcupines as well as the prickly fur of spiny mice, spiny pocket mice and spiny rats. They are also found on afrotherian tenrecs, marsupial spiny bandicoots and on echidnas, of the monotremes. An ancient synapsid, '' Dimetrodon'', had extremely long spines on its backbone that were joined together with a web of skin that formed a sail-like structure. Many mammalian species, like cats and fossas, also have penile spines. The Mesozoic eutriconodont mammal ''Spinolestes'' already displayed spines similar to those of modern spiny mice. Fish Spines are found in the rays o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Test (biology)
In biology, a test is the hard shell of some spherical marine animals and protists, notably sea urchins and microorganisms such as testate foraminiferans, radiolarians, and testate amoebae. The term is also applied to the covering of scale insects. The related Latin term testa is used for the hard seed coat of plant seeds. Etymology The anatomical term "test" derives from the Latin ''testa'' (which means a rounded bowl, amphora or bottle). Structure The test is a skeletal structure, made of hard material such as calcium carbonate, silica, chitin or composite materials. As such, it allows the protection of the internal organs and the attachment of soft flesh. In sea urchins The test of sea urchins is made of calcium carbonate, strengthened by a framework of calcite monocrystals, in a characteristic "stereomic" structure. These two ingredients provide sea urchins with a great solidity and a moderate weight, as well as the capacity to regenerate the mesh from the cuticle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intertidal
The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of Marine habitat, habitats with various species of Marine life, life, such as seastars, Sea urchin, sea urchins, and many species of coral with regional differences in biodiversity. Sometimes it is referred to as the ''littoral zone'' or ''shore, seashore'', although those can be defined as a wider region. The well-known area also includes steep rocky Cliff, cliffs, sandy Beach, beaches, Bog, bogs or wetlands (e.g., vast Mudflat, mudflats). The area can be a narrow strip, as in Pacific island, Pacific islands that have only a narrow tidal range, or can include many meters of shoreline where shallow beach slopes interact with high tidal excursion. The peritidal zone is similar but somewhat wider, extending from above the highest tide level to below the lowest. Organisms in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tube Feet
Tube feet (technically podia) are small active tubular projections on the oral face of an echinoderm, whether the arms of a starfish, or the undersides of sea urchins, sand dollars and sea cucumbers; they are more discreet though present on brittle stars, and have only a feeding function in feather stars. They are part of the water vascular system. Structure and function Tube feet function in locomotion, feeding, and respiration. The tube feet in a starfish are arranged in grooves along the arms. They operate through hydraulic pressure. They are used to pass food to the oral mouth at the center, and can attach to surfaces. A starfish that is inverted turns one arm over and attaches it to a solid surface, and levers itself the right way up. Tube feet allow these different types of animals to stick to the ocean floor and move slowly. Each tube foot consists of two parts: the ampulla and the podium. The ampulla is a water-filled sac contained in the body of the animal that contain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
