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Palaeoniscids
The Palaeonisciformes (Palaeoniscida) are an extinct order of early ray-finned fishes (Actinopterygii). Palaeonisciformes '' sensu lato'' first appeared in the fossil record in the Late Silurian and last appeared in the Late Cretaceous. The name is derived from the Ancient Greek words παλαιός (''palaiós'', ancient) and ὀνίσκος (''oniskos'', 'cod-fish' or woodlouse), probably pertaining to the organization of the fishes' scales, similar to the exoskeletal plating of woodlice. In an early interpretation of the group, the Palaeonisciformes are divided in two suborders: Palaeoniscoidei (includes ''Palaeoniscum'' and fossil taxa with a broadly similar appearance) and Platysomoidei (includes ''Platysomus'' and other deep-bodied early actinopterygians). These groupings are considered paraphyletic today. In the cladistic sense, Palaeonisciformes ''sensu stricto'' should only refer to the Permian ''Palaeoniscum'', the name giving taxon, and all other taxa that fall o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palaeoniscum
''Palaeoniscum'' (from el, παλαιός , 'ancient' and el, ὀνίσκος 'cod-fish' or 'woodlouse') is an extinct genus of ray-finned fish from the Permian period (Guadalupian-Lopingian) of Europe (England, Germany, Czech Republic?, Turkey), North America (Greenland), and possibly other regions. The genus was named ''Palaeoniscum'' in 1818 by Henri Marie Ducrotay de Blainville, but was later misspelled as ''Palaeoniscus'' by Blainville and other authors (notably Louis Agassiz). ''Palaeoniscum'' belongs to the family Palaeoniscidae. The type species ''Palaeoniscum freieslebeni'' was named after Johann Carl Freiesleben (1774–1846), mining commissioner of Saxony. ''P. freieslebeni'' is the most common taxon in the Wuchiapingian aged Kupferschiefer and Marl Slate, where it constitutes 80% of all fish fossils. ''Palaeoniscum'' had a torpedo-shaped body in length, with a deeply forked caudal fin and tall dorsal fin, indicating that it was a fast swimmer. It was probably an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sensu Stricto
''Sensu'' is a Latin word meaning "in the sense of". It is used in a number of fields including biology, geology, linguistics, semiotics, and law. Commonly it refers to how strictly or loosely an expression is used in describing any particular concept, but it also appears in expressions that indicate the convention or context of the usage. Common qualifiers ''Sensu'' is the ablative case of the noun ''sensus'', here meaning "sense". It is often accompanied by an adjective (in the same case). Three such phrases are: *''sensu stricto'' – "in the strict sense", abbreviation ''s.s.'' or ''s.str.''; *''sensu lato'' – "in the broad sense", abbreviation ''s.l.''; *''sensu amplo'' – "in a relaxed, generous (or 'ample') sense", a similar meaning to ''sensu lato''. Søren Kierkegaard uses the phrase ''sensu eminenti'' to mean "in the pre-eminent r most important or significantsense". When appropriate, comparative and superlative adjectives may also be used to convey the meaning o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sturgeons
Sturgeon is the common name for the 27 species of fish belonging to the family Acipenseridae. The earliest sturgeon fossils date to the Late Cretaceous, and are descended from other, earlier acipenseriform fish, which date back to the Early Jurassic period, some 174 to 201 million years ago. They are one of two living families of the Acipenseriformes alongside paddlefish (Polyodontidae). The family is grouped into four genera: ''Acipenser'' (which is paraphyletic, containing many distantly related sturgeon species), ''Huso'', ''Scaphirhynchus,'' and ''Pseudoscaphirhynchus''. Two species ('' A. naccarii'' and '' A. dabryanus'') may be extinct in the wild, and one ('' P. fedtschenkoi'') may be entirely extinct. Sturgeons are native to subtropical, temperate and sub-Arctic rivers, lakes and coastlines of Eurasia and North America. Sturgeons are long-lived, late-maturing fishes with distinctive characteristics, such as a heterocercal caudal fin similar to those of sharks, and an ... [...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(†) * Coc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palaeozoic
The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ''zōḗ'' (), "life", meaning "ancient life" ). It is the longest of the Phanerozoic eras, lasting from , and is subdivided into six geologic periods (from oldest to youngest): # Cambrian # Ordovician # Silurian # Devonian # Carboniferous # Permian The Paleozoic comes after the Neoproterozoic Era of the Proterozoic Eon and is followed by the Mesozoic Era. The Paleozoic was a time of dramatic geological, climatic, and evolutionary change. The Cambrian witnessed the most rapid and widespread diversification of life in Earth's history, known as the Cambrian explosion, in which most modern phyla first appeared. Arthropods, molluscs, fish, amphibians, reptiles, and synapsids all evolved during the Paleozoic. Life began in the ocean but eve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Louis Agassiz
Jean Louis Rodolphe Agassiz ( ; ) FRS (For) FRSE (May 28, 1807 – December 14, 1873) was a Swiss-born American biologist and geologist who is recognized as a scholar of Earth's natural history. Spending his early life in Switzerland, he received a PhD at Erlangen and a medical degree in Munich. After studying with Georges Cuvier and Alexander von Humboldt in Paris, Agassiz was appointed professor of natural history at the University of Neuchâtel. He emigrated to the United States in 1847 after visiting Harvard University. He went on to become professor of zoology and geology at Harvard, to head its Lawrence Scientific School, and to found its Museum of Comparative Zoology. Agassiz is known for observational data gathering and analysis. He made institutional and scientific contributions to zoology, geology, and related areas, including multivolume research books running to thousands of pages. He is particularly known for his contributions to ichthyological classification, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ichthyologists
Ichthyology is the branch of zoology devoted to the study of fish, including bony fish (Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 33,400 species of fish had been described as of October 2016, with approximately 250 new species described each year. Etymology The word is derived from the Greek words ἰχθύς, ''ikhthus'', meaning "fish"; and λογία, ''logia'', meaning "to study". History The study of fish dates from the Upper Paleolithic Revolution (with the advent of "high culture"). The science of ichthyology was developed in several interconnecting epochs, each with various significant advancements. The study of fish receives its origins from humans' desire to feed, clothe, and equip themselves with useful implements. According to Michael Barton, a prominent ichthyologist and professor at Centre College, "the earliest ichthyologists were ''hunters and gatherers'' who had learned how to obtain the most usefu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Systematics
Biological systematics is the study of the diversification of living forms, both past and present, and the relationships among living things through time. Relationships are visualized as evolutionary trees (synonyms: cladograms, phylogenetic trees, phylogenies). Phylogenies have two components: branching order (showing group relationships) and branch length (showing amount of evolution). Phylogenetic trees of species and higher taxa are used to study the evolution of traits (e.g., anatomical or molecular characteristics) and the distribution of organisms (biogeography). Systematics, in other words, is used to understand the evolutionary history of life on Earth. The word systematics is derived from the Latin word '' systema,'' which means systematic arrangement of organisms. Carl Linnaeus used 'Systema Naturae' as the title of his book. Branches and applications In the study of biological systematics, researchers use the different branches to further understand the relationshi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acropholis Stensioei
''Acropholis'' is an extinct genus of prehistoric bony fish that lived during the Permian epoch of Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ....A. López-Arbarello, O. W. R. Rauhut, and E. Cerdeño. 2010. The Triassic fish faunas of the Cuyana Basin, Western Argentina. Palaeontology 53:249-276 References Palaeonisciformes Prehistoric ray-finned fish genera {{Palaeonisciformes-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladistia
Cladistia is a clade of bony fishes whose only living members are the bichirs. Their major synapomorphies are a heterocercal tail in which the dorsal fin has independent rays, and a posteriorly elongated parasphenoid. Cladistia are the earliest diverging branch of living Actinopterygii, sister group of Actinopteri, the group which includes all other living ray finned fish. Aside from bichirs, other extinct fish groups thought to be members of the group include the Scanilepiformes, known from the Triassic period. Taxonomy Based on work done by Lund 2000 * Order †Guildayichthyiformes Lund 2000 ** Family †Guildayichthyidae Lund 2000 *** Genus †'' Guildayichthys'' Lund 2000 **** Species †'' Guildayichthys carnegiei'' Lund 2000 *** Genus †''Discoserra'' Lund 2000 **** Species †''Discoserra pectinodon'' Lund 2000 * Order Polypteriformes Bleeker 1859 ** Genus †'' Latinopollia'' Meunier and Gayet 1998 *** Species †'' Latinopollia suarezi'' (Meunier & Gayet 1996) M ... [...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 Liv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monophyletic
In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic groups are typically characterised by shared derived characteristics ( synapomorphies), which distinguish organisms in the clade from other organisms. An equivalent term is holophyly. The word "mono-phyly" means "one-tribe" in Greek. Monophyly is contrasted with paraphyly and polyphyly as shown in the second diagram. A ''paraphyletic group'' consists of all of the descendants of a common ancestor minus one or more monophyletic groups. A '' polyphyletic group'' is characterized by convergent features or habits of scientific interest (for example, night-active primates, fruit trees, aquatic insects). The features by which a polyphyletic group is differentiated from others are not inherited from a common ancestor. These definitions have tak ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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