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Hemicyclaspis
''Hemicyclaspis'' ( or 'semicircle plate') is an extinct genus of primitive jawless fish, closely related to '' Cephalaspis'', that lived in the Late Silurian ( Pridoli) to Devonian period in what is now Europe and North America. A typical cephalaspid, ''Hemicyclaspis'' had a heavily armored, shovel-shaped headshield. It is thought to have been a better swimmer than most of its relatives because of its powerful tail, stabilizing dorsal fin and the keel-shaped hydrodynamic In physics, physical chemistry and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids – liquids and gases. It has several subdisciplines, including (the study of air and other gases in moti ... edges of its head shield. ''Hemicyclaspis'' probably foraged the ocean floor for food. ''Hemicyclaspis'' grew to a length of 5 inches (13 centimeters) and would most likely have fed on particles from the muddy sea bed. References * Parker, Steve. Dinosaurus: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteostraci Genera
The class Osteostraci (meaning "bony shells") is an extinct taxon of bony-armored jawless fish, termed "ostracoderms", that lived in what is now North America, Europe and Russia from the Middle Silurian to Late Devonian. Anatomically speaking, the osteostracans, especially the Devonian species, were among the most advanced of all known agnathans. This is due to the development of paired fins, and their complicated cranial anatomy. The osteostracans were more similar to lampreys than to jawed vertebrates in possessing two pairs of semicircular canals in the inner ear, as opposed to the three pairs found in the inner ears of jawed vertebrates. They are thought to be the sister-group to pituriaspids, and together, these two taxa of jawless vertebrates are the sister-group of gnathostomes. Several synapomorphies support this hypothesis, such as the presence of: sclerotic ossicles, paired pectoral fins, a dermal skeleton with three layers (a basal layer of isopedin, a middle layer o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thyestes (fish)
''Thyestes'' is an extinct genus of osteostraci, osteostracan agnathan vertebrate of Europe whose fossils are found in Middle to Late Ludlow epoch, Ludlow-aged marine strata of Late Silurian Europe. Individuals of ''Thyestes'' superficially resembled ''Cephalaspis'', but were more closely related to ''Auchenaspis'' and ''Tremataspis''. References Osteostraci genera Silurian fish of Europe {{Paleo-jawless-fish-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluid Dynamics
In physics, physical chemistry and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids – liquids and gases. It has several subdisciplines, including (the study of air and other gases in motion) and (the study of water and other liquids in motion). Fluid dynamics has a wide range of applications, including calculating forces and moment (physics), moments on aircraft, determining the mass flow rate of petroleum through pipeline transport, pipelines, weather forecasting, predicting weather patterns, understanding nebulae in interstellar space, understanding large scale Geophysical fluid dynamics, geophysical flows involving oceans/atmosphere and Nuclear weapon design, modelling fission weapon detonation. Fluid dynamics offers a systematic structure—which underlies these practical disciplines—that embraces empirical and semi-empirical laws derived from flow measurement and used to solve practical problems. The solution to a fl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian Fish Of North America
The Devonian ( ) is a geologic period and system of the Paleozoic era during the Phanerozoic eon, spanning 60.3 million years from the end of the preceding Silurian period at million years ago ( Ma), to the beginning of the succeeding Carboniferous period at Ma. It is the fourth period of both the Paleozoic and the Phanerozoic. It is named after Devon, South West England, where rocks from this period were first studied. The first significant evolutionary radiation of life on land occurred during the Devonian, as free- sporing land plants (pteridophytes) began to spread across dry land, forming extensive coal forests which covered the continents. By the middle of the Devonian, several groups of vascular plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants ( pteridospermatophytes) appeared. This rapid evolution and colonization process, which had begun during the Silurian, is known as the Silurian-Devonian Terrestrial Revolu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Devonian Fish Of Europe
Early may refer to: Places in the United States * Early, Iowa, a city * Early, Texas, a city * Early Branch, a stream in Missouri * Early County, Georgia * Fort Early, Georgia, an early 19th century fort Music * Early B, stage name of Jamaican dancehall and reggae deejay Earlando Arrington Neil (1957–1994) * Early James, stage name of American singer-songwriter Fredrick Mullis Jr. (born 1993) * ''Early'' (Scritti Politti album), 2005 * ''Early'' (A Certain Ratio album), 2002 * Early Records, a record label Other uses * Early (name), a list of people and fictional characters with the given name or surname * Early effect, an effect in transistor physics * Early, a synonym for ''hotter'' in stellar classification See also * * The Earlies, a 21st century band * Earley (other) * Earlie Earlie is a masculine given name which may refer to: * Earlie Fires (born 1947), American jockey * Earlie Thomas (1945–2022), American National Football League player * Earlie End ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
England
England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It shares Anglo-Scottish border, a land border with Scotland to the north and England–Wales border, another land border with Wales to the west, and is otherwise surrounded by the North Sea to the east, the English Channel to the south, the Celtic Sea to the south-west, and the Irish Sea to the west. Continental Europe lies to the south-east, and Ireland to the west. At the 2021 United Kingdom census, 2021 census, the population was 56,490,048. London is both List of urban areas in the United Kingdom, the largest city and the Capital city, capital. The area now called England was first inhabited by modern humans during the Upper Paleolithic. It takes its name from the Angles (tribe), Angles, a Germanic peoples, Germanic tribe who settled du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Herefordshire
Herefordshire ( ) is a Ceremonial counties of England, ceremonial county in the West Midlands (region), West Midlands of England, bordered by Shropshire to the north, Worcestershire to the east, Gloucestershire to the south-east, and the Welsh counties of Monmouthshire and Powys to the west. The city of Hereford is the largest settlement and county town. The county is one of the most rural in England, with an area of and a population of 187,034, giving a density of 88/km2 (228/sq mi). After Hereford (53,112) the largest settlements are Leominster (10,938), Ross-on-Wye (10,582), and Ledbury (8,862). For Local government in England, local government purposes Herefordshire is a Unitary authorities of England, unitary authority area. The centre of Herefordshire is lowland which is crossed by the River Wye and its tributary, the River Lugg, Lugg. To the east are the Malvern Hills, a National Landscape, national landscape, which straddle the boundary with Worcestershire. The south ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ledbury
Ledbury is a market town and civil parish in the county of Herefordshire, England, lying east of Hereford, and west of the Malvern Hills. It has a significant number of Tudor style timber-framed structures, in particular along Church Lane and High Street. One of the most outstanding is Ledbury Market Hall, built in 1617, located in the town centre. Other notable buildings include the parish church of St. Michael and All Angels, the Painted Room (containing sixteenth-century frescoes), the Old Grammar School, the Barrett-Browning memorial clock tower (designed by Brightwen Binyon and opened in 1896 to house the library until 2015), nearby Eastnor Castle and the St. Katherine's Hospital site. Founded , this is a rare surviving example of a hospital complex, with hall, chapel, a Master's House (fully restored and opened in March 2015 to house the Library), almshouses and a timber-framed barn. History Ledbury is a borough whose origins date to around AD 690. In the Domesday ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorsal Fin
A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found in most fish, in mammals such as whales, and in extinct ancient marine reptiles such as ichthyosaurs. Most have only one dorsal fin, but some have two or three. Wildlife biologists often use the distinctive nicks and wear patterns which develop on the dorsal fins of whales to identify individuals in the field. The bones or cartilages that support the dorsal fin in fish are called pterygiophores. Functions The main purpose of the dorsal fin is usually to stabilize the animal against rolling and to assist in sudden turns. Some species have further adapted their dorsal fins to other uses. The sunfish uses the dorsal fin (and the anal fin Fins are moving appendages protruding from the body of fish that interact with water to ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish
A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can be grouped into the more basal (phylogenetics), basal jawless fish and the more common jawed fish, the latter including all extant taxon, living cartilaginous fish, cartilaginous and bony fish, as well as the extinct placoderms and acanthodians. In a break to the long tradition of grouping all fish into a single Class (biology), class (Pisces), modern phylogenetics views fish as a paraphyletic group. Most fish are ectotherm, cold-blooded, their body temperature varying with the surrounding water, though some large nekton, active swimmers like white shark and tuna can hold a higher core temperature. Many fish can communication in aquatic animals#Acoustic, communicate acoustically with each other, such as during courtship displays. The stud ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Armoured Fish
Placoderms (from Ancient Greek πλάξ 'plax'', ''plakos''' plate' and δέρμα 'derma'''skin') are vertebrate animals of the class Placodermi, an extinct group of prehistoric fish known from Paleozoic fossils during the Silurian and the Devonian periods. While their endoskeletons are mainly cartilaginous, their head and thorax were covered by articulated armoured plates (hence the name), and the rest of the body was scaled or naked depending on the species. Placoderms were among the first jawed fish (their jaws likely evolved from the first pair of gill arches), as well as the first vertebrates to have true teeth. They were also the first fish clade to develop pelvic fins, the second set of paired fins and the homologous precursor to hindlimbs in tetrapods. 380-million-year-old fossils of three other genera, ''Incisoscutum'', ''Materpiscis'' and '' Austroptyctodus'', represent the oldest known examples of live birth. Placoderms are thought to be paraphyletic, consisti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalaspidomorphi
Cephalaspidomorphi (alternatively called Monirhina, or simply cephalaspids) is a Class (biology), class of agnatha, jawless fishes that is presently regarded as uniting the Osteostraci, osteostracans, Galeaspida, galeaspids and Pituriaspida, pituriaspids. Most biologists regard this taxon as extinct, but the name is still sometimes used in the classification of lampreys because they were once thought to be descended. If lampreys are included they would extend the known range of the group from the Silurian and Devonian periods, when they are traditionally assumed to have lived, to the Holocene, present day. Modern works typically assume the cephalaspidimorphs to be the closest relatives of jawed fishes, who may have emerged from within them; if this is true, they would survive if the Gnathostomata, jawed fish are included. The cephalaspidomorphs possessed armored head-shields, a heterocercal tail fin, and in some groups paired pectoral fins. Biology and morphology Cephalaspidomorphs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
