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Homosteus
''Homosteus'' is a genus of flattened arthrodire placoderm from the Middle Devonian. Fossils are found primarily in Eifelian-epoch aged strata of Europe, Canada, Greenland, and Estonia. All of the species had comparatively large, flattened heads with, as suggested by the upward opening orbits, upward-pointing eyes. These adaptations suggest that the various species were benthic predators. A study on ''Titanichthys'', in contrast, suggests that species of ''Homosteus'' may have been filter-feeders instead. ''Homosteus'' specimens from the Old Red Sandstone of Scotland are known to be significantly radioactive, on the order of 1.2 * 104 gamma/min/g ic Notably, ''Homosteus'' specimens are the only fish fossils from the Old Red Sandstone to show significant radioactivity. This suggests that these specimens became radioactive from the animals ingesting radioactive isotopes in life (e.g., through ingesting radioactive sediment), rather than radioactive isotopes being absorbed by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homostiidae
Homostiidae is a family of flattened arthrodire placoderms from the Early to Middle Devonian. Fossils appear in various strata in Europe, Russia, Morocco, Australia, Canada and Greenland. Many homostiids have " toothless" jaws, and large sizes. suggesting that many homostiids were probably filter feeders, like the also noticeably flattened Rhincodon typus. All homostiids have flattened and elongated skulls. According to Denison 1978, primitive homostiids have moderately long median dorsal plates, whereas in "advanced" homostiids, the median dorsal tends to be short and broad. Obruchev (1964) placed the following primitive genera ''Euleptaspis'', ''Lophostracon'' and ''Luetkeichthys'' in a separate family, "Euleptaspididae," and Ørvig (1969), claimed that the Euleptaspidids were totally unrelated to Homostiidae proper (i.e., being neither related to, nor ancestral), but, according to Denison, did not clearly explain his reasons why this was so. Genera ''Angarichthys'' A compa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eifelian
The Eifelian is the first of two faunal stages in the Middle Devonian Epoch. It lasted from 393.3 ± 1.2 million years ago to 387.7 ± 0.8 million years ago. It was preceded by the Emsian Stage and followed by the Givetian Stage. North American subdivisions of the Eifelian Stage include Southwood, and part of Cazenovia (or Cazenovian). Name and definition The Eifelian is named after the Eifel Mountains of Western Germany, which exposed the GSSP section at the Wetteldorf Richtschnitt outcrop. The base of the Eifelian is defined by the start of the '' Polygnathus partitus'' conodont zone. This layer lies within the Upper Heisdorf Formation, below the base of the Lauch Formation. Extinctions The end of the Eifelian was marked by a biological crisis known as the Kačák Event, a two-part interval of extinction which led to ecological turnover among ammonoids, conodonts, and other free-swimming animals. In deep marine waters, the event is indicated by anoxic black shales. Ther ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Old Red Sandstone
The Old Red Sandstone is an assemblage of rocks in the North Atlantic region largely of Devonian age. It extends in the east across Great Britain, Ireland and Norway, and in the west along the northeastern seaboard of North America. It also extends northwards into Greenland and Svalbard. These areas were a part of the ancient continent of Euramerica, Euramerica/Laurussia. In Britain it is a lithostratigraphy, lithostratigraphic unit (a sequence of rock strata) to which Stratigraphy, stratigraphers accord Geological unit#Lithostratigraphic units, supergroup status and which is of considerable importance to early paleontology. For convenience the short version of the term, ORS is often used in literature on the subject. The term was coined to distinguish the sequence from the younger New Red Sandstone which also occurs widely throughout Britain. Sedimentology The Old Red Sandstone describes a suite of sedimentary rocks deposited in a variety of environments during the Devonian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orkney Islands
Orkney (; sco, Orkney; on, Orkneyjar; nrn, Orknøjar), also known as the Orkney Islands, is an archipelago in the Northern Isles of Scotland, situated off the north coast of the island of Great Britain. Orkney is 10 miles (16 km) north of the coast of Caithness and has about 70 islands, of which 20 are inhabited. The largest island, the Mainland, has an area of , making it the sixth-largest Scottish island and the tenth-largest island in the British Isles. Orkney’s largest settlement, and also its administrative centre, is Kirkwall. Orkney is one of the 32 council areas of Scotland, as well as a constituency of the Scottish Parliament, a lieutenancy area, and an historic county. The local council is Orkney Islands Council, one of only three councils in Scotland with a majority of elected members who are independents. The islands have been inhabited for at least years, originally occupied by Mesolithic and Neolithic tribes and then by the Picts. Orkney was col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinichthys
''Dinichthys'' (from el, δεινός , 'terrible' and el, ἰχθύς 'fish') is an extinct monospecific genus of giant, marine arthrodire placoderm from the Late Devonian (Famennian stage), comparable in size, shape, and ecological role to the better-known ''Dunkleosteus''. Fossils were recovered from the Ohio Shale Formation along the Olentangy River in Delaware County, Ohio. Classification History ''Dinichthys'' was originally described in 1868 by John Newberry on the basis of an incomplete skull roof and mandibles (holotype AMNH 81). Subsequently, many unrelated large arthrodires were originally classified together within this genus, including species now assigned to ''Dunkleosteus'', '' Eastmanosteus'', and ''Titanichthys''. Notably, the type species of ''Dunkleosteus'' was originally described as ''Dinichthys terrelli'' by Newberry in 1873, and was later separated into ''Dunkleosteus'' by Jean-Pierre Lehman in 1956. ''Dunkleosteus'' was still thought to be close ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sympatric
In biology, two related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter one another. An initially interbreeding population that splits into two or more distinct species sharing a common range exemplifies sympatric speciation. Such speciation may be a product of reproductive isolation – which prevents hybrid offspring from being viable or able to reproduce, thereby reducing gene flow – that results in genetic divergence. Sympatric speciation may, but need not, arise through secondary contact, which refers to speciation or divergence in allopatry followed by range expansions leading to an area of sympatry. Sympatric species or taxa in secondary contact may or may not interbreed. Types of populations Four main types of population pairs exist in nature. Sympatric populations (or species) contrast with parapatric populations, which contact one another in adjacent but not shared ranges and do no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canning Land
Canning is a method of food preservation in which food is processed and sealed in an airtight container (jars like Mason jars, and steel and tin cans). Canning provides a shelf life that typically ranges from one to five years, although under specific circumstances, it can be much longer. A freeze-dried canned product, such as canned dried lentils, could last as long as 30 years in an edible state. In 1974, samples of canned food from the wreck of the ''Bertrand'', a steamboat that sank in the Missouri River in 1865, were tested by the National Food Processors Association. Although appearance, smell, and vitamin content had deteriorated, there was no trace of microbial growth and the 109-year-old food was determined to be still safe to eat. History and development French origins During the first years of the Napoleonic Wars, the French government offered a hefty cash award of 12,000 francs to any inventor who could devise a cheap and effective method of preserving la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emsian
The Emsian is one of three faunal stages in the Early Devonian Epoch. It lasted from 407.6 ± 2.6 million years ago to 393.3 ± 1.2 million years ago. It was preceded by the Pragian Stage and followed by the Eifelian Stage. It is named after the Ems river in Germany. The GSSP is located in the Zinzil'ban Gorge in the Kitab State Geological Reserve of Uzbekistan, above the contact with the Madmon Formation. In North America the Emsian Stage is represented by Sawkill or Sawkillian time. Biological events During this period, earliest known agoniatitid ammonoid fossils began appearing within this stage after first appearing in previous stage and began to evolutionarily radiate within this stage, in which a new ammonoid order Goniatitida rises in the end of Zlichovian stage (Siberian representation; corresponds to early Eifelian and after the end of Early Devonian, before 391.9 mya). Later agoniatitid ammonoids would die out in the Taghanic event in the upper middle Givetian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norway
Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and the archipelago of Svalbard also form part of Norway. Bouvet Island, located in the Subantarctic, is a dependency of Norway; it also lays claims to the Antarctic territories of Peter I Island and Queen Maud Land. The capital and largest city in Norway is Oslo. Norway has a total area of and had a population of 5,425,270 in January 2022. The country shares a long eastern border with Sweden at a length of . It is bordered by Finland and Russia to the northeast and the Skagerrak strait to the south, on the other side of which are Denmark and the United Kingdom. Norway has an extensive coastline, facing the North Atlantic Ocean and the Barents Sea. The maritime influence dominates Norway's climate, with mild lowland temperatures on the se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trionyx
''Trionyx'' is a genus of softshell turtles belonging to the family Trionychidae. In the past many species in the family were classified in this genus, but today '' T. triunguis'', the African or Nile softshell turtle, is the only extant softshell still classified as ''Trionyx''. The other species still assigned to this genus are only known from fossils. ''T. triunguis'' is a relatively large, aquatic piscivore. Species The list of species follows a 2017 review of the Trionychidae by Georgios L. Georgalis and Walter G. Joyce. * '' Trionyx triunguis'' ( Forsskål, 1775) – African or Nile softshell turtle * † '' Trionyx pliocenicus'' Fucini, 1912 – Pliocene of Tuscany (Italy) * † '' Trionyx vindobonensis'' (Peters, 1855) – Miocene of Vienna (Austria) The following species are considered valid trionychid taxa, but with uncertain phylogenetic relationships. They are only referred to ''Trionyx'' provisionally due to its historic status as a wastebasket taxon Wasteba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aruküla
Aruküla is a small borough ( et, alevik) in Harju County, northern Estonia. It is the administrative centre of Raasiku Parish. Aruküla had a population of 2,113 on 1 January 2020. Aruküla has a station on the Elron's eastern route. Gallery File:Aruküla vana kultuurimaja.JPG, Aruküla old culture house File:Aruküla vana laululava.jpg, Aruküla song festival grounds in the 1960s. File:Aruküla kivi 2005.jpg, Aruküla glacial erratic File:Kolhoosimaja.jpg, Former centre of Aruküla kolkhoz A kolkhoz ( rus, колхо́з, a=ru-kolkhoz.ogg, p=kɐlˈxos) was a form of collective farm in the Soviet Union. Kolkhozes existed along with state farms or sovkhoz., a contraction of советское хозяйство, soviet ownership or .... File:View to Aruküla.JPG, View to Aruküla File:Aruküla lauluväljak.JPG, Aruküla song court File:Aruküla esmamainimist tähistav kivi.JPG, Stone, indicating Aruküla first mention See also * Aruküla Basic School * Aruküla ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteosarcoma
An osteosarcoma (OS) or osteogenic sarcoma (OGS) (or simply bone cancer) is a cancerous tumor in a bone. Specifically, it is an aggressive malignant neoplasm that arises from primitive transformed cells of mesenchymal origin (and thus a sarcoma) and that exhibits osteoblastic differentiation and produces malignant osteoid. Osteosarcoma is the most common histological form of primary bone sarcoma. It is most prevalent in teenagers and young adults. Signs and symptoms Many patients first complain of pain that may be worse at night, may be intermittent and of varying intensity and may have been occurring for a long time. Teenagers who are active in sports often complain of pain in the lower femur, or immediately below the knee. If the tumor is large, it can present as overt localised swelling. Sometimes a sudden fracture is the first symptom because the affected bone is not as strong as normal bone and may fracture abnormally with minor trauma. In cases of more deep-seated tumors t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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