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Ray-finned Fish
Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or horny spines (rays), as opposed to the fleshy, lobed fins that characterize the class Sarcopterygii (lobe-finned fish). These actinopterygian fin rays attach directly to the proximal or basal skeletal elements, the radials, which represent the link or connection between these fins and the internal skeleton (e.g., pelvic and pectoral girdles). By species count, actinopterygians dominate the vertebrates, and they constitute nearly 99% of the over 30,000 species of fish. They are ubiquitous throughout freshwater and marine environments from the deep sea to the highest mountain streams. Extant species can range in size from ''Paedocypris'', at , to the massive ocean sunfish, at , and the long-bodied oarfish, at . The vast majority of Actino ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ludlow Epoch
In the geological timescale, the Ludlow Epoch (from 427.4 ± 0.5 million years ago to 423.0 ± 2.3 million years ago) occurred during the Silurian Period, after the end of the Homerian Age. It is named for the town of Ludlow in Shropshire, England. The Ludlow Epoch is subdivided into two stages: Gorstian and Ludfordian. Paleontology Arthropods See also *Ludlow Group The Ludlow Group are geologic formations deposited during the Ludlow epoch of the Silurian period in the British Isles, in areas of England, Ireland, Scotland, and Wales. Formations This group contains the following formations in descending o ... References *03 Geological epochs {{geochronology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leafy Seadragon
The leafy seadragon (''Phycodurus eques'') or Glauert's seadragon, is the only member of the genus ''Phycodurus'' and is a marine fish in the family Syngnathidae, which includes seadragons, pipefish, and seahorses. It is found along the southern and western coasts of Australia. The name is derived from the appearance, with long leaf-like protrusions coming from all over the body. These protrusions are not used for propulsion; they serve only as camouflage. The leafy seadragon propels itself by means of a pectoral fin on the ridge of its neck and a dorsal fin on its back closer to the tail end. These small fins are almost completely transparent and difficult to see as they undulate minutely to move the creature sedately through the water, completing the illusion of floating seaweed. Popularly known as "leafies", it is the marine emblem of the state of South Australia and a focus for local marine conservation. Taxonomy The generic name ''Phycodurus'' is derived from the Gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vertebrate
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () (chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, with currently about 69,963 species described. Vertebrates comprise such groups as the following: * jawless fish, which include hagfish and lampreys * jawed vertebrates, which include: ** cartilaginous fish (sharks, rays, and ratfish) ** bony vertebrates, which include: *** ray-fins (the majority of living bony fish) *** lobe-fins, which include: **** coelacanths and lungfish **** tetrapods (limbed vertebrates) Extant vertebrates range in size from the frog species ''Paedophryne amauensis'', at as little as , to the blue whale, at up to . Vertebrates make up less than five percent of all described animal species; the rest are invertebrates, which lack vertebral columns. The vertebrates traditionally include the hagfish, which do not have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
McGraw-Hill Education
McGraw Hill is an American educational publishing company and one of the "big three" educational publishers that publishes educational content, software, and services for pre-K through postgraduate education. The company also publishes reference and trade publications for the medical, business, and engineering professions. McGraw Hill operates in 28 countries, has about 4,000 employees globally, and offers products and services to about 140 countries in about 60 languages. Formerly a division of The McGraw Hill Companies (later renamed McGraw Hill Financial, now S&P Global), McGraw Hill Education was divested and acquired by Apollo Global Management in March 2013 for $2.4 billion in cash. McGraw Hill was sold in 2021 to Platinum Equity for $4.5 billion. Corporate History McGraw Hill was founded in 1888 when James H. McGraw, co-founder of the company, purchased the ''American Journal of Railway Appliances''. He continued to add further publications, eventually establishing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteichthyes
Osteichthyes (), popularly referred to as the bony fish, is a diverse superclass of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartilage. The vast majority of fish are members of Osteichthyes, which is an extremely diverse and abundant group consisting of 45 orders, and over 435 families and 28,000 species. It is the largest class of vertebrates in existence today. The group Osteichthyes is divided into the ray-finned fish ( Actinopterygii) and lobe-finned fish ( Sarcopterygii). The oldest known fossils of bony fish are about 425 million years old, which are also transitional fossils, showing a tooth pattern that is in between the tooth rows of sharks and bony fishes. Osteichthyes can be compared to Euteleostomi. In paleontology the terms are synonymous. In ichthyology the difference is that Euteleostomi presents a cladistic view which includes the terrestria ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class (biology)
In biological classification, class ( la, classis) is a taxonomic rank, as well as a taxonomic unit, a taxon, in that rank. It is a group of related taxonomic orders. Other well-known ranks in descending order of size are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order. History The class as a distinct rank of biological classification having its own distinctive name (and not just called a ''top-level genus'' ''(genus summum)'') was first introduced by the French botanist Joseph Pitton de Tournefort in his classification of plants that appeared in his ''Eléments de botanique'', 1694. Insofar as a general definition of a class is available, it has historically been conceived as embracing taxa that combine a distinct ''grade'' of organization—i.e. a 'level of complexity', measured in terms of how differentiated their organ systems are into distinct regions or sub-organs—with a distinct ''type'' of construction, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adolf Von Klein
Adolf (also spelt Adolph or Adolphe, Adolfo and when Latinised Adolphus) is a given name used in German-speaking countries, Scandinavia, the Netherlands and Flanders, France, Italy, Spain, Portugal, Latin America and to a lesser extent in various Central European and East European countries with non-Germanic languages, such as Lithuanian Adolfas and Latvian Ādolfs. Adolphus can also appear as a surname, as in John Adolphus, the English historian. The female forms Adolphine and Adolpha are far more rare than the male names. The name is a compound derived from the Old High German ''Athalwolf'' (or ''Hadulf''), a composition of ''athal'', or ''adal'', meaning "noble" (or '' had(u)''-, meaning "battle, combat"), and ''wolf''. The name is cognate to the Anglo-Saxon name '' Æthelwulf'' (also Eadulf or Eadwulf). The name can also be derived from the ancient Germanic elements "Wald" meaning "power", "brightness" and wolf (Waldwulf). Due to negative associations with Adolf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teleostei
Teleostei (; Greek ''teleios'' "complete" + ''osteon'' "bone"), members of which are known as teleosts ), is, by far, the largest infraclass in the class Actinopterygii, the ray-finned fishes, containing 96% of all extant species of fish. Teleosts are arranged into about 40 orders and 448 families. Over 26,000 species have been described. Teleosts range from giant oarfish measuring or more, and ocean sunfish weighing over , to the minute male anglerfish ''Photocorynus spiniceps'', just long. Including not only torpedo-shaped fish built for speed, teleosts can be flattened vertically or horizontally, be elongated cylinders or take specialised shapes as in anglerfish and seahorses. The difference between teleosts and other bony fish lies mainly in their jaw bones; teleosts have a movable premaxilla and corresponding modifications in the jaw musculature which make it possible for them to protrude their jaws outwards from the mouth. This is of great advantage, enabling them ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holostei
Holostei is a group of ray-finned bony fish. It is divided into two major clades, the Halecomorphi, represented by a single living species, the bowfin ('' Amia calva''), as well as the Ginglymodi, the sole living representatives being the gars (Lepisosteidae), represented by seven living species in two genera ('' Atractosteus'', '' Lepisosteus''). The earliest members of the clade appeared during the Early Triassic, over 250 million years ago. Holostei was thought to be regarded as paraphyletic. However, a recent study provided evidence that the Holostei are the closest living relates of the Teleostei, both within the Neopterygii. This was found from the morphology of the Holostei, for example presence of a paired vomer. Holosteans are closer to teleosts than are the chondrosteans, the other group intermediate between teleosts and cartilaginous fish, which are regarded as (at the nearest) a sister group to the Neopterigii. The spiracles of holosteans are reduced to vestigia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neopterygii
Neopterygii (from Greek νέος ''neos'' 'new' and πτέρυξ ''pteryx'' 'fin') is a subclass of ray-finned fish (Actinopterygii). Neopterygii includes the Holostei and the Teleostei, of which the latter comprise the vast majority of extant fishes, and over half of all living vertebrate species. While living holosteans include only freshwater taxa, teleosts are diverse in both freshwater and marine environments. Many new species of teleosts are scientifically described each year. Fossil evidence for crown group neopterygians goes back at least 251 million years to the Induan stage of the Early Triassic epoch, however, one study incorporating morphological data from fossils and molecular data from nuclear and mitochondrial DNA, places this divergence date at least 284 mya (million years ago), during the Artinskian stage of the Early Permian. Another study suggests an even earlier split (360 myr ago, near the Devonian-Carboniferous boundary). Evolution and diversity L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chondrostei
Chondrostei is a group of non-neopterygian ray-finned fish, while the term originally referred to a paraphyletic group of all non-neopterygian ray-finned fish, it was redefined by Patterson in 1982 to be a clade comprising the Acipenseriformes (which includes sturgeon and paddlefish) and their extinct relatives. Taxa commonly suggested to represent relatives of the Acipenseriformes include the Triassic marine fish ''Birgeria'' and the Saurichthyiformes, but their the relationship with the Acipenseriformes has been strongly challenged on cladistical grounds. Coccolepididae, a group of small weakly ossified Jurassic and Cretaceous fish found in both marine and freshwater environments, have been suggested to be close relatives of the Acipenseriformes, however, this has never been subject to cladistical analysis. Classification *Acipenseriformes **Acipenseridae — sturgeons **Polyodontidae — paddlefishes **Chondrosteidae(†) ** Errolichthyidae(†) * Cheirolepidiformes(†) *Cocc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Actinopteri
Actinopteri is the sister group of Cladistia in the class Actinopterygii (ray-finned fish). Dating back to the Permian period, the Actinopteri comprise the Chondrostei (sturgeons and paddlefish) and the Neopterygii (bowfin, gars, and teleosts). In other words, the Actinopteri include all extant actinopterygians, minus the Polypteridae (bichirs). Classification The following cladogram summarizes the evolutionary relationships of extant Actinopteri. Divergence time for each clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English ter ... in mya are based on: References {{Taxonbar, from=Q343460 Ray-finned fish taxonomy Vertebrate unranked clades ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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