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Starfish
Starfish or sea stars are Star polygon, star-shaped echinoderms belonging to the class (biology), class Asteroidea (). Common usage frequently finds these names being also applied to brittle star, 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, tropics, tropical zones to frigid, polar regions of Earth, polar regions. They are found from the intertidal zone down to abyssal zone, 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 fe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echinoderm
An echinoderm () is any animal of the phylum Echinodermata (), which includes starfish, brittle stars, sea urchins, sand dollars and sea cucumbers, as well as the sessile sea lilies or "stone lilies". While bilaterally symmetrical as larvae, as adults echinoderms are recognisable by their usually five-pointed radial symmetry (pentamerous symmetry), and are found on the sea bed at every ocean depth from the intertidal zone to the abyssal zone. The phylum contains about 7,600 living species, making it the second-largest group of deuterostomes after the chordates, as well as the largest marine-only phylum. The first definitive echinoderms appeared near the start of the Cambrian. Echinoderms are important both ecologically and geologically. Ecologically, there are few other groupings so abundant in 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 ... [...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. 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 they hide under rocks and even w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linckia Laevigata
''Linckia laevigata'' (sometimes called the "blue ''Linckia''" or blue star) is a species of sea star in the shallow waters of tropical Indo-Pacific. Description and characteristics The variation ("polymorphism", in this case, a "color morph") most commonly found is pure blue, dark blue, or light blue, although observers find the aqua, purple, or orange variation throughout the ocean. These sea stars may grow up to in diameter, with rounded tips at each of the arms; some individuals may bear lighter or darker spots along each of their arms. Individual specimens are typically firm in texture, possessing the slightly tubular, elongated arms common to most of other members of the Family (biology), family Ophidiasteridae, and usually possessing short, yellowish tube feet. An inhabitant of coral reefs and sea grass beds, this species is relatively common and is typically found in sparse density throughout its range. Blue stars live subtidally, or sometimes intertidally, on fine (s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echinaster Serpentarius
''Echinaster'' is a well-studied and common genus of starfish containing ~30 species and is the second-largest genus found within the family Echinasteridae. The genera ''Henricia'' and ''Echinaster'' encompass 90% of all the species found within the family Echinasteridae. It contains 30 species, however the number of species in this genus is still debatable because of uncertainty within the genera. This genus is currently sub-divided into two sub-genera: ''Echinaster'' and ''Othilia'', evolutionary relationships between the sub-genera is not understood. ''Echinaster'' are found in the Pacific, Atlantic and Indian oceans, with most species being studied in the Gulf of Mexico and Brazil. The sub-genera ''Othilia'' is thought to encompass species mainly found in the Gulf of Mexico and Brazil. ''Echinaster'' is often one of the most studied species within the family Echinasteridae and is often used to find evolutionary relationships. Many species found within ''Echinaster'' are red, o ... [...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 and 16 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 New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla .... 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 fam ... [...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, 187 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intertidal Zone
The intertidal zone or foreshore is the area above water level at low tide and underwater at high tide; in other words, it is the part of the littoral zone within the tidal range. This area can include several types of habitats with various species of life, such as sea stars, 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 intertidal zone also includes steep rocky cliffs, sandy beaches, bogs or wetlands (e.g., vast mudflats). This area can be a narrow strip, such 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 well-adapted to their environment, facing high ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paxillosida
The Paxillosida are a large 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. The order is divided into these families: * family Astropectinidae Gray, 1840 * family Benthopectinidae Verrill, 1899 * family Ctenodiscidae Sladen, 1889 * family Goniopectinidae Verrill, 1889 * family Luidiidae Sladen, 1889 * family Paleobenthopectinidae Blake, 1984 † * family Porcellanasteridae Sladen, 1883 * family ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protoreaster Nodosus
''Protoreaster nodosus'', commonly known as the horned sea star or chocolate chip sea star, is a species of sea star found in the warm, shallow waters of the Indo-Pacific region. They are sometimes seen in the marine aquarium trade or dried and sold as curios. Description ''P. nodosus'' possess rows of spines or "horns"; black conical points arranged in a single row, radially on the dorsal side, which may erode and become blunt. These dark protrusions can intimidate possible predators by looking frightening or dangerous. On the ventral side, tube feet, purple in color (or pale, transparent pink), are arranged in rows on each arm. Most horned sea stars found are a roughly rigid five-pointed star-shape with tapering arms to the end, although there are anomalies like four or six-armed specimens; they may grow up to in diameter. The sea stars are usually colored in shades of red or brown, but can be light tan, resembling the color of cookie dough. This coloration, combined with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marine Invertebrates
Marine invertebrates are invertebrate animals that live in marine habitats, and make up most of the macroscopic life in the oceans. It is a polyphyletic blanket term that contains all marine animals except the marine vertebrates, including the non-vertebrate members of the phylum Chordata such as lancelets, sea squirts and salps. As the name suggests, marine invertebrates lack any mineralized tissue, mineralized axial skeleton, axial endoskeleton, i.e. the vertebral column, and some have evolved a rigid seashell, shell, test (biology), test or exoskeleton for protection and/or aquatic locomotion, locomotion, while others rely on hydroskeleton, internal fluid pressure to support their bodies. Marine invertebrates have a large variety of body plans, and have been categorized into over 30 phyla. 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 l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forcipulatida
The Forcipulatida are an order (biology), order of sea stars, containing three families and 49 genera. Description Forcipulatids share with the Brisingida, 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 North 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 another taxonomy, with 7 families and 64 genera: * Family Asteriidae Gray, 1840 * Family Heliasteridae Viguier, 1878 * Family Pedicellasteridae Perrier, 1884 * Family Pycnopodiidae Fisher, 1928 * Family Stichasteridae Perrie ... [...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 (biology), family of starfish in the monotypic order (biology), order Spinulosida. The family includes eight genera and about 133 species found on the seabed in various habitats around the world. Taxonomy Echinast ... Verrill, 1870 References Echinoderm orders {{Asteroidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
