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Starfish
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 below the surface. Starfish are marine invertebrates. They typically have a central disc and usually five arms, though some species have a larger number of arms. The aboral or upper surface may be smooth, granular or spiny, and is covered with overlapping plates. Many species are brightly coloured in various shades of red or orange, while others are blue, grey or brown. Starfish have tube feet operated by a hydraulic system and a mouth at the centre of the oral or lower surface. ... [...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] |
Brittle Star
Brittle stars, serpent stars, or ophiuroids (; ; referring to the serpent-like arms of the brittle star) 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 in length on the largest specimens. The Ophiuroidea contain two large clades, Ophiurida (brittle stars) and Euryalida (basket stars). Over 2,000 species of brittle stars live today. More than 1,200 of these species are found in deep waters, greater than 200 m deep. Range The ophiuroids diverged in the Early Ordovician, about 500 million years ago. Ophiuroids can be found today in all of the major marine provinces, from the poles to the tropics. Basket stars are usually confined to the deeper parts of this range; Ophiuroids are known even from abyssal (>6,000 m) depths. However, brittle stars are also common members of reef communities, where t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fromia Monilis
''Fromia monilis'', common name necklace starfish or tiled starfish, is a species of starfish belonging to the family Goniasteridae. Description ''Fromia monilis'' can reach a diameter of about . Tips of the arms and the disc center of this starfish are bright red, while the remaining parts are paler, forming large plates. Fromia monilis (Seastar).jpg Image:Fromia monilis (Sea star).jpg, In Timor. Image:Elegant Necklace Starfish (Fromia monilis) (8488880713).jpg, ''Fromia monilis'' (Sabah, Malaisia) The appearance of this sea star can be highly variable (colors, plates, presence of plates on the central disc, armpits...), and its identification using picture can be difficult, as many other species (like ''Fromia nodosa'') can have a very similar aspect. Distribution This species can be found in the Indian Ocean and Western Pacific, from the Andaman islands up to Australia and Japan. Ecology It feeds on encrusting sponge Sponges, the members of the phylum Porifera (; ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valvatida
The Valvatida are an order of starfish in the class Asteroidea, which contains 695 species in 172 genera in 17 families. Description The order encompasses both tiny species, which are only a few millimetres in diameter, like those in the genus '' Asterina'', and species which can reach up to 75 cm, such as species in the genus '' Thromidia''. Almost all species in this order have five arms with tube feet. This order is primarily identified by the presence of conspicuous marginal ossicles, which characterize most of the species. Most members of this order have five arms and two rows of tube feet with suckers. Some species have paxillae and in some, the main pedicellariae are clamp-like and recessed into the skeletal plates. This group includes the cushion star, and the leather star. Families According to the World Register of Marine Species, the following families are included in Valvatida: * family Acanthasteridae Gervais, 1841 * family Archasteridae Viguier, 1878 * f ... [...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] |
Brisingida
The Brisingids are deep-sea-dwelling starfish in the order Brisingida. Description These starfish have between 6 to 18 long, attenuated arms which they use for suspension feeding. Other characteristics include a single series of marginals, a fused ring of disc plates, the lack of actinal plates, a spool-like ambulacral column, reduced abactinal plates, and crossed pedicellariae. They are 40 times the size of disk radius and have 7-20 flexible spiny arms. Distribution Brisingida occur in a number of deep-sea locations, particularly in the Caribbean and New Zealand. This type of species are found of varying size especially in the eastern Pacific Ocean at a depth of 1,820–2,418 m. Taxonomy The Brisingida contain two families, with 18 genera: *Family Brisingidae, G.O. Sars, 1875 **Genus ''Astrolirus'', Fisher, 1917 — (two species) **Genus '' Astrostephane'', Fisher, 1917 — (two species) **Genus ''Brisinga'' Asbjørnsen, 1856 (synonym: ''Craterobrisinga'', Fisher, 1916) — ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paxillosida
The Paxillosida are a large order (biology), order of sea stars. Characteristics Paxillosida adults lack an anus and have no suckers on their tube feet. They do not develop the brachiolaria stage in their early development.Matsubara, M., Komatsu, M., Araki, T., Asakawa, S., Yokobori, S.-I., Watanabe, K. & Wada, H. (2005) The phylogenetic status of Paxillosida (Asteroidea) based on complete mitochondrial DNA sequences. Molecular Genetics and Evolution, 36, 598–605 They possess marginal plates, and have sessile pedicellariae. They mostly inhabit soft-bottomed environments of sand or mud. Systematics Recent analyses suggest Paxillosida may be a sister taxon of Asterina (starfish), Asterina. The order is divided into these families: * family Astropectinidae Gray, 1840 * family Ctenodiscidae Sladen, 1889 * family Goniopectinidae Verrill, 1889 * family Luidiidae Sladen, 1889 * family Porcellanasteridae Sladen, 1883 * family Pseudarchasteridae * family Radiasteridae Fisher, 1916 Fil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intertidal Zone
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 habitats with various species of life, such as seastars, sea urchins, and many species of coral with regional differences in biodiversity. Sometimes it is referred to as the ''littoral zone'' or '' seashore'', although those can be defined as a wider region. The well-known area also includes steep rocky cliffs, sandy beaches, bogs or wetlands (e.g., vast mudflats). The area can be a narrow strip, as in 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 the intertidal zone are adapted to an environment of harsh extremes, living in water pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinulosida
The Spinulosida are an order of sea stars containing at least 120 species in seven genera and one family. Spinulosids completely lack pedicellariae and have a delicate skeletal arrangement. Their name comes from the presence of numerous low spines on the aboral (upper) surface. No fossil spinulosids have yet been found. Taxonomy The following family is recognised by the World Register of Marine Species: * Echinasteridae The Echinasteridae are a family of starfish in the monotypic order Spinulosida. The family includes eight genera and about 133 species found on the seabed in various habitats around the world. Taxonomy Echinasteridae contains eight genera and ... Verrill, 1870 References Echinoderm orders {{Asteroidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forcipulatida
The Forcipulatida are an order of sea stars, containing three families and 49 genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat .... Description Forcipulatids share with the brisingid sea stars distinctive pedicellariae, consisting of a short stalk with three skeletal Ossicle (echinoderm), ossicles. Unlike that group, however, the forcipulatids tend to have more robust bodies. The order includes some well-known species, such as the common starfish, ''Asterias rubens''. This order can be commonly found from Nor Carolina in the United States all the way to Santos in Brazil. Phylogeny The order is divided into three families: * Family Asteriidae — 39 genera * Family Heliasteridae — two genera * Family Zoroasteridae — eight genera World Register of Marine Species gives ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Notomyotida
Benthopectinidae is a family of sea stars containing at least 75 species in eight genera. It is the only family in the monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ... order Notomyotida. These asteroids are deep-sea dwelling and have flexible arms. The inner dorso-lateral surface of the arms contain characteristic longitudinal muscle bands. Eight genera of deep-water species make up the majority of the family benthopectinidae, and many of its members are expected to have a greater range than is currently recognized. Shin. (2015). A New Record of Sea Star Genus Nearchaster (Asteroidea: Notomyotida: Benthopectinidae) from East Sea, Korea. Animal Systematics, Evolution and Diversity, 31(2), 135–138. https://doi.org/10.5635/ASED.2015.31.2.135 Taxonomy Nine genera are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Invertebrates
Marine invertebrates are the invertebrates that live in marine habitats. Invertebrate is a blanket term that includes all animals apart from the vertebrate members of the chordate phylum. Invertebrates lack a vertebral column, and some have evolved a shell or a hard exoskeleton. As on land and in the air, marine invertebrates have a large variety of body plans, and have been categorised into over 30 phyla. They make up most of the macroscopic life in the oceans. Evolution The earliest animals were marine invertebrates, that is, vertebrates came later. Animals are multicellular eukaryotes, and are distinguished from plants, algae, and fungi by lacking cell walls. Marine invertebrates are animals that inhabit a marine environment apart from the vertebrate members of the chordate phylum; invertebrates lack a vertebral column. Some have evolved a shell or a hard exoskeleton. The earliest animals may belong to the genus '' Dickinsonia'', 571 million to 539 million years ago. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
