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Andreolepis Hedei
''Andreolepis'' is an extinct genus of prehistoric fish, which lived around 420 million years ago. It was described by Walter Gross in 1968 based on scales found in the Hemse Formation in Gotland, Sweden. It is placed in the monogeneric family Andreolepididae and is generally regarded as a primitive member of the class Actinopterygii based on its ganoid scale structure; however some new research regards it as a stem group of osteichthyans. Researchers have used microremains of an ''Andreolepsis'' to determine its origins and found that it dated back to the late Silurian. ''Andreolepis'' was capable of shedding its teeth by basal resorption, which is considered a rather primitive mode of tooth replacement. This makes it informative about the evolution of teeth. Fossil remains are mostly limited to scales, platelets and fragmented bones. At first only the species ''A. hedei'' was described. Scales, platelets and a spine from the Central Urals in Russia have thereafter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ganoine
Ganoine or ''ganoin'' is a glassy, often multi-layered mineralized tissue that covers the scales, cranial bones and fin rays in some non-teleost ray-finned fishes, such as gars, bichirs, and coelacanths. It is composed of rod-like, pseudoprismatic apatite crystallites, with less than 5% of organic matter. Existing fish groups featuring ganoin are bichirs and gars, but ganoin is also characteristic of several extinct taxa. It is a characteristic component of ganoid scales. Ganoine is an ancient feature of ray-finned fishes, being found for example on the scales of stem group actinopteryigian ''Cheirolepis''. While often considered a synapomorphic character of ray-finned fishes, ganoine or ganoine-like tissues are also found on the extinct acanthodii. It has been suggested that ganoine is homologous to tooth enamel in vertebrates or even considered a type of enamel. Ganoine indeed contains amelogenin-like proteins and has a mineral content similar to that of tetrapod Tetrap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anaspida
Anaspida ("without shield") is an extinct group of primitive jawless vertebrates that lived primarily during the Silurian period, and became extinct soon after the start of the Devonian. They were classically regarded as the ancestors of lampreys. Anaspids were small marine agnathans that lacked a heavy bony shield and paired fins, but have a striking highly hypocercal tail. They first appeared in the early Silurian, and flourished until the early Devonian, when they disappear from the fossil record. Anatomy Compared to other prehistoric agnathan groups, such as the Heterostraci and Osteostraci, anaspids did not possess a bony shield or armor, hence their name. The anaspid head and body are instead covered in an array of small, weakly mineralized scales, with a row of massive scutes running down the back, and, at least confirmed among the birkeniids, the body was covered in rows of tile-like scales made of aspidine, an acellular bony tissue. Anaspids all had prominent, latera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acanthodii
Acanthodii or acanthodians is an extinct class of gnathostomes (jawed fishes), typically considered a paraphyletic group. They are currently considered to represent a grade of various fish lineages leading up to the extant Chondrichthyes, which includes living sharks, rays, and chimaeras. Acanthodians possess a mosaic of features shared with both osteichthyans (bony fish) and chondrichthyans (cartilaginous fish). In general body shape, they were similar to modern sharks, but their epidermis was covered with tiny rhomboid platelets like the scales of holosteians (gars, bowfins). A lower Silurian species, ''Fanjingshania renovata'', attributed to Climatiiformes is the oldest chondrichthyan with known anatomical features. The popular name "spiny sharks" is because they were superficially shark-shaped, with a streamlined body, paired fins, a strongly upturned tail, and stout, largely immovable bony spines supporting all the fins except the tail—hence, "spiny sharks". However, ... [...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] |
Great Britain
Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island and the ninth-largest island in the world. It is dominated by a maritime climate with narrow temperature differences between seasons. The 60% smaller island of Ireland is to the west—these islands, along with over 1,000 smaller surrounding islands and named substantial rocks, form the British Isles archipelago. Connected to mainland Europe until 9,000 years ago by a landbridge now known as Doggerland, Great Britain has been inhabited by modern humans for around 30,000 years. In 2011, it had a population of about , making it the world's third-most-populous island after Java in Indonesia and Honshu in Japan. The term "Great Britain" is often used to refer to England, Scotland and Wales, including their component adjoining islands. Great Britain and Northern Ireland now constitute the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nova Zemlya
Novaya Zemlya (, also , ; rus, Но́вая Земля́, p=ˈnovəjə zʲɪmˈlʲa, ) is an archipelago in northern Russia. It is situated in the Arctic Ocean, in the extreme northeast of Europe, with Cape Flissingsky, on the northern island, considered the easternmost point of Europe. To Novaya Zemlya's west lies the Barents Sea and to the east is the Kara Sea. Novaya Zemlya consists of two main islands, the northern Severny Island and the southern Yuzhny Island, which are separated by the Matochkin Strait. Administratively, it is incorporated as Novaya Zemlya District, one of the twenty-one in Arkhangelsk Oblast, Russia.Law #65-5-OZ Municipally, it is incorporated as Novaya Zemlya Urban Okrug.Law #258-vneoch.-OZ The population of Novaya Zemlya as of the 2010 Census was about 2,429, of whom 1,972 resided in Belushya Guba, an urban settlement that is the administrative center of Novaya Zemlya District. The indigenous population (from 1872 to the 1950s when it was resettl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
West Khatanzeya Formation
West or Occident is one of the four cardinal directions or points of the compass. It is the opposite direction from east and is the direction in which the Sun sets on the Earth. Etymology The word "west" is a Germanic word passed into some Romance languages (''ouest'' in French, ''oest'' in Catalan, ''ovest'' in Italian, ''oeste'' in Spanish and Portuguese). As in other languages, the word formation stems from the fact that west is the direction of the setting sun in the evening: 'west' derives from the Indo-European root ''*wes'' reduced from ''*wes-pero'' 'evening, night', cognate with Ancient Greek ἕσπερος hesperos 'evening; evening star; western' and Latin vesper 'evening; west'. Examples of the same formation in other languages include Latin occidens 'west' from occidō 'to go down, to set' and Hebrew מַעֲרָב maarav 'west' from עֶרֶב erev 'evening'. Navigation To go west using a compass for navigation (in a place where magnetic north is the same dire ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latvia
Latvia ( or ; lv, Latvija ; ltg, Latveja; liv, Leţmō), officially the Republic of Latvia ( lv, Latvijas Republika, links=no, ltg, Latvejas Republika, links=no, liv, Leţmō Vabāmō, links=no), is a country in the Baltic region of Northern Europe. It is one of the Baltic states; and is bordered by Estonia to the north, Lithuania to the south, Russia to the east, Belarus to the southeast, and shares a maritime border with Sweden to the west. Latvia covers an area of , with a population of 1.9 million. The country has a temperate seasonal climate. Its capital and largest city is Riga. Latvians belong to the ethno-linguistic group of the Balts; and speak Latvian, one of the only two surviving Baltic languages. Russians are the most prominent minority in the country, at almost a quarter of the population. After centuries of Teutonic, Swedish, Polish-Lithuanian and Russian rule, which was mainly executed by the local Baltic German aristocracy, the independent R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estonia
Estonia, formally the Republic of Estonia, is a country by the Baltic Sea in Northern Europe. It is bordered to the north by the Gulf of Finland across from Finland, to the west by the sea across from Sweden, to the south by Latvia, and to the east by Lake Peipus and Russia. The territory of Estonia consists of the mainland, the larger islands of Saaremaa and Hiiumaa, and over 2,200 other islands and islets on the eastern coast of the Baltic Sea, covering a total area of . The capital city Tallinn and Tartu are the two largest urban areas of the country. The Estonian language is the autochthonous and the official language of Estonia; it is the first language of the majority of its population, as well as the world's second most spoken Finnic language. The land of what is now modern Estonia has been inhabited by '' Homo sapiens'' since at least 9,000 BC. The medieval indigenous population of Estonia was one of the last " pagan" civilisations in Europe to adopt Ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Himmiste Beds Formation
Himmiste is a village in Saaremaa Parish, Saare County, Estonia. (retrieved 28 July 2021) Before the administrative reform in 2017, the village was in Lääne-Saare Parish Lääne-Saare Parish ( et, Lääne-Saare vald) was a rural municipality of Estonia, in Saare County. It was located on the western part of Saaremaa island. The municipality has a population of ca 7,200 and an area of 807 km2. Lääne-Saare .... References Villages in Saare County {{Saare-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_(3149758934).jpg "Click for more on -> Ganoine")
