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List Of Acanthodians
This list of acanthodian genera is an attempt to create a comprehensive listing of all genera that have ever been included in the subclass Acanthodii, excluding purely vernacular terms. The list includes all commonly accepted genera, but also genera that are now considered invalid, doubtful (''nomina dubia''), or were not formally published (''nomina nuda''), as well as junior synonyms of more established names, and genera that are no longer considered acanthodians. Not counting their descendants, the modern chondricthyans, all acanthodians are extinct. Extinct genera are marked with a dagger ( †) Naming conventions and terminology Naming conventions and terminology follow the International Code of Zoological Nomenclature. Technical terms used include: * Junior synonym: A name which describes the same taxon as a previously published name. If two or more genera are formally designated and the type specimens are later assigned to the same genus, the first to be published (in chro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesacanthus Parexus Ischnacanthus
''Mesacanthus'' ('middle spine') is an extinct genus of acanthodian fish from early Devonian Scotland. It is among the more primitive of the Devonian acanthodians. Description ''Mesacanthus'' body fossils have pectoral, pelvic, anal and dorsal fin spine (zoology), spines, as well as a pair of prepelvic spines, which are intermediate between the pectoral and pelvic fin spines. They also have small, unornamented, diamond shaped scales. According to Agassiz, the genus also has a distinct tail in which the upper lobe extends to a sharp point and the lower lobe forms a small triangle. Overall the genus is small (average length = 30mm) and fairly conservative, anatomically speaking, for acanthodians. Agassiz, L. (1833). Recherches sur les poissons fossiles.. (Vol. 1). chez l'auteur. Taxonomy The genus was erected by Ramsay Traquair in 1888 to accommodate certain species that had been previously assigned to Acanthodes by Louis Agassiz.Traquair, R. H. (1888). Old Red Sandstone fishes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Severnaya Zemlya
Severnaya Zemlya (russian: link=no, Сéверная Земля́ (Northern Land), ) is a archipelago in the Russian high Arctic. It lies off Siberia's Taymyr Peninsula, separated from the mainland by the Vilkitsky Strait. This archipelago separates two marginal seas of the Arctic Ocean, the Kara Sea in the west and the Laptev Sea in the east. Severnaya Zemlya was first noted in 1913 and first charted in 1930–32, making it the last sizeable archipelago on Earth to be explored. Administratively, the islands form part of Russia's Krasnoyarsk Krai. In Soviet times there were a number of research stations in different locations, but currently there are no human inhabitants in Severnaya Zemlya, except for the Prima Polar Station near Cape Baranov. The largest glacier in the Russian Federation, the Academy of Sciences Glacier, is located in Severnaya Zemlya. The archipelago is notable as well in connection with the ongoing multiyear Arctic sea ice decline. Until recently, ic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hybodontiformes
Hybodontiformes, commonly called hybodonts, are an extinct group of shark-like chondrichthyans, which existed from the late Devonian to the Late Cretaceous. They form the group of Elasmobranchii closest to neoselachians, the clade of modern sharks and rays. Hybodonts were named and are distinguished based on their conical tooth shape. They are also noted for the presence of a spine on each of their two dorsal fins. They were abundant in marine and freshwater environments during the late Paleozoic and early Mesozoic, but were rare in open marine environments by the end of the Jurassic, having been largely replaced by modern sharks, though they were still common in freshwater and marginal marine habitats. They survived until the end of the Cretaceous, before going extinct. Etymology The term hybodont comes from the Greek word ''ὕβος'' or ''ὑβός'' meaning hump or hump-backed and ''ὀδούς, ὀδοντ'' meaning tooth. This name was given based on their conical compres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ischnacanthiformes
Ischanacanthiformes is a prehistoric order of Acanthodii or spiny sharks found in Canada, Ukraine and United Kingdom. Members of this order were nektonic carnivores, eating animals that swim rather than plankton. They had slender builds, light armor, deeply inserted spines, shark-like teeth, and two dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through c ...s. Some species were around 2 meters (6.56 feet) long. It was described by Berg in 1940. References Acanthodii Prehistoric fish orders {{Acanthodii-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poracanthodes
''Poracanthodes'' is a genus of acanthodian fish belonging to the Ischnacanthidae family. It lived during the Late Silurian period. Its fossils have been discovered in Estonia and China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and .... References Ischnacanthiformes Silurian cartilaginous fish of Asia Silurian fish of Europe {{Acanthodii-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acanthopora (fish)
''Echinopora'' is a genus of stony corals in the family Merulinidae. Species The following species are currently recognized: * ''Echinopora ashmorensis'' Veron, 1990 * ''Echinopora forskaliana'' (Milne Edwards & Haime, 1849) * ''Echinopora fruticulosa'' Klunzinger, 1879 * ''Echinopora gemmacea'' (Lamarck, 1816) * ''Echinopora hirsutissima'' Milne Edwards & Haime, 1849 * ''Echinopora horrida'' Dana, 1846 * ''Echinopora irregularis'' Veron, Turak & DeVantier, 2000 * ''Echinopora lamellosa'' (Esper, 1795) * ''Echinopora mammiformis'' (Nemenzo, 1959) * ''Echinopora pacificus'' Veron, 1990 * ''Echinopora robusta'' Veron, 2000 * ''Echinopora spinulosa'' Brüggemann * ''Echinopora tiranensis ''Echinopora'' is a genus of stony corals in the family Merulinidae. Species The following species are currently recognized: * ''Echinopora ashmorensis'' Veron, 1990 * ''Echinopora forskaliana'' (Milne Edwards & Haime, 1849) * ''Echinopora f ...'' Veron, Turak & DeVantier, 2000 Reference ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, smaller islands. With an area of , Australia is the largest country by area in Oceania and the world's List of countries and dependencies by area, sixth-largest country. Australia is the oldest, flattest, and driest inhabited continent, with the least fertile soils. It is a Megadiverse countries, megadiverse country, and its size gives it a wide variety of landscapes and climates, with Deserts of Australia, deserts in the centre, tropical Forests of Australia, rainforests in the north-east, and List of mountains in Australia, mountain ranges in the south-east. The ancestors of Aboriginal Australians began arriving from south east Asia approximately Early human migrations#Nearby Oceania, 65,000 years ago, during the Last Glacial Period, last i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia and it is located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. Comprising the westernmost peninsulas of Eurasia, it shares the continental landmass of Afro-Eurasia with both Africa and Asia. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south and Asia to the east. Europe is commonly considered to be Boundaries between the continents of Earth#Asia and Europe, separated from Asia by the drainage divide, watershed of the Ural Mountains, the Ural (river), Ural River, the Caspian Sea, the Greater Caucasus, the Black Sea and the waterways of the Turkish Straits. "Europe" (pp. 68–69); "Asia" (pp. 90–91): "A commonly accepted division between Asia and E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carboniferous
The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carboniferous'' means "coal-bearing", from the Latin '' carbō'' ("coal") and '' ferō'' ("bear, carry"), and refers to the many coal beds formed globally during that time. The first of the modern 'system' names, it was coined by geologists William Conybeare and William Phillips in 1822, based on a study of the British rock succession. The Carboniferous is often treated in North America as two geological periods, the earlier Mississippian and the later Pennsylvanian. Terrestrial animal life was well established by the Carboniferous Period. Tetrapods (four limbed vertebrates), which had originated from lobe-finned fish during the preceding Devonian, became pentadactylous in and diversified during the Carboniferous, including early amphibian line ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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