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Microraptorians
Microraptoria (Greek, μίκρος, ''mīkros'': "small"; Latin, ''raptor'': "one who seizes") is a clade of basal dromaeosaurid theropod dinosaurs. Definitive microraptorians lived during the Barremian to Aptian stages of the Early Cretaceous in China. Probable microraptorian ichnotaxon '' Dromaeosauriformipes'' was discovered from the Jinju Formation of South Korea, and some fragmentary Late Cretaceous paravian fossils in North America have been described as putative members of this clade. Many are known for long feathers on their legs and may have been semiarboreal powered fliers, some of which were even capable of launching from the ground.. Most microraptorians were relatively small; adult specimens of ''Microraptor'' range between ) and weigh up to , making them some of the smallest known non-avialan dinosaurs.Holtz, Thomas R. Jr. (2011) ''Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages,'Winter 2010 Appendix./ref> Description Microrapt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the Latin word for the white limestone known as chalk. The chalk of northern France and the white cliffs of south-eastern England date from the Cretaceous Period. Climate During the Late Cretaceous, the climate was warmer than present, although throughout the period a cooling trend is evident. The tropics became restricted to equatorial regions and northern latitudes experienced markedly more seasonal climatic conditions. Geography Due to plate tectonics, the Americas were gradually moving westward, causing the Atlantic Ocean to expand. The Western Interior Seaway divided North America into eastern and western halves; Appalachia and Laramidia. India maintained a northward course towards Asia. In the Southern Hemisphere, Aus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aptian
The Aptian is an age (geology), age in the geologic timescale or a stage (stratigraphy), stage in the stratigraphic column. It is a subdivision of the Early Cretaceous, Early or Lower Cretaceous epoch (geology), Epoch or series (stratigraphy), Series and encompasses the time from 121.4 ± 1.0 annum, Ma to 113.0 ± 1.0 Ma (million years ago), approximately. The Aptian succeeds the Barremian and precedes the Albian, all part of the Lower/Early Cretaceous. The Aptian partly overlaps the upper part of the Western Europe, Western European Urgonian Stage. The Selli Event, also known as OAE1a, was one of two oceanic anoxic events in the Cretaceous Period, which occurred around 120 annum, Ma and lasted approximately 1 to 1.3 million years, being marked by enhanced silicate weathering, as well as ocean acidification. The Aptian extinction was a minor extinction event hypothesized to have occurred around 116 to 117 Ma. Stratigraphic definitions The Aptian was named after the small city o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jehol Biota
The Jehol Biota includes all the living organisms – the ecosystem – of northeastern China between 133 and 120 million years ago. This is the Lower Cretaceous ecosystem which left fossils in the Yixian Formation and Jiufotang Formation. These deposits are composed of layers of tephra and sediment. It is also believed to have left fossils in the Sinuiju series of North Korea.Li, Quanguo, Gao, Ke-qin (2007). "Lower Cretaceous vertebrate fauna from the Sinuiju basin, North Korea as evidence of geographic extension of the Jehol Biota into the Korean Peninsula". ''Journal of Vertebrate Paleontology'' 27, supplement to number (3). pp.106A. The ecosystem in the Lower Cretaceous was dominated by wetlands and numerous lakes (not rivers, deltas, or marine habitats). Rainfall was seasonal, alternating between semiarid and mesic conditions. The climate was temperate. The Jehol ecosystem was interrupted periodically by ash eruptions from volcanoes to the west. The word "Jehol" is a historic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jiufotang Formation
The Jiufotang Formation () is an Early Cretaceous geological formation in Chaoyang, Liaoning which has yielded fossils of feathered dinosaurs, primitive birds, pterosaurs, and other organisms (see Jehol Biota). It is a member of the Jehol group. The exact age of the Jiufotang has been debated for years, with estimates ranging from the Late Jurassic to the Early Cretaceous. New Uranium–lead dating, uranium-lead dates reveal the formation is deposited in the Aptian stage of the Early Cretaceous. Fossils of ''Microraptor'' and ''Jeholornis'' are from the Jiufotang. Fossil content Choristoderans Fish Mammaliamorphs Several mammaliamorph specimens have been found from the Jiufotang, but only a few have been formally described and named. Ornithischians Pterosaurs Saurischians A large titanosaur is present in the formation. Enantiornithines Euornithines Non-ornithothoracean theropods Crustaceans Plants See also * Yixian Formation * List of dinosa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yixian Formation
The Yixian Formation (; formerly Romanization of Chinese, transcribed as Yihsien Formation or Yixiang Formation) is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans the Barremian stage of the Early Cretaceous. It is known for its exquisitely preserved fossils, and is mainly composed of basalts interspersed with siliciclastic sediments. Research history The potential importance of the Yixian Formation was initially recognized during the time the Empire of Japan occupied China's Rehe Province, Rehe ("Jehol") Province after the Defense of the Great Wall in 1933. Many Japanese scientists had noticed fossil remains of extinct fish and reptiles, possibly the champsosaurs. These initial fossil discoveries made by Japanese scientists vanished once World War II ended in 1945. By 1949, when administration of the area passed to the Chinese Communist Party and its leader Mao Zedong, the fossils of Yixian were studied only by Chinese scientists. It was not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinornithosaurus Dave NGMC91
''Sinornithosaurus'' (derived from a combination of Latin and Ancient Greek, Greek, meaning 'Chinese bird-lizard') is a genus of Feathered dinosaurs, feathered dromaeosaurid dinosaur from the early Cretaceous Period (geology), Period (late Barremian) of the Yixian Formation in what is now China. It was the fifth non–avian feathered dinosaurs, feathered dinosaur genera, genus discovered by 1999. The original specimen was collected from the Sihetun locality of western Liaoning. It was found in the Jianshangou beds of the Yixian Formation, dated to 124.5 million years ago. Additional specimens have been found in the younger Dawangzhangzi bed, dating to around 122 million years ago. Xu Xing described ''Sinornithosaurus'' and performed a phylogenetic analysis which demonstrated that it is basal, or primitive, among the dromaeosaurs. He has also demonstrated that features of the skull and shoulder are very similar to ''Archaeopteryx'' and other Avialae, avialans. Together these two fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinosaur Size
Size is an important aspect of dinosaur paleontology, of interest to both the general public and professional scientists. Dinosaurs show some of the most extreme variations in size of any land animal group, ranging from tiny hummingbirds, which can weigh as little as two grams, to the extinct titanosaurs, such as ''Argentinosaurus'' and '' Bruhathkayosaurus'' which could weigh as much as . The latest evidence suggests that dinosaurs' average size varied through the Triassic, early Jurassic, late Jurassic and Cretaceous periods, and dinosaurs probably only became widespread during the early or mid Jurassic. Predatory theropod dinosaurs, which occupied most terrestrial carnivore niches during the Mesozoic, most often fall into the category when sorted by estimated weight into categories based on order of magnitude, whereas recent predatory carnivoran mammals peak in the range of . The mode of Mesozoic dinosaur body masses is between one and ten metric tonnes. This contrasts sha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arboreal
Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally (scansorial), but others are exclusively arboreal. The habitats pose numerous mechanical challenges to animals moving through them and lead to a variety of anatomical, behavioral and ecological consequences as well as variations throughout different species. Cartmill, M. (1985). "Climbing". pp. 73–88 ''In'': Hildebrand, Milton; Bramble, Dennis M.; Liem, Karel F.; Wake, David B. (editors) (1985). ''Functional Vertebrate Morphology''. Cambridge, Massachusetts: Belknap Press. 544 pp. . Furthermore, many of these same principles may be applied to climbing without trees, such as on rock piles or mountains. Some animals are exclusively arboreal in habitat, such as tree snails. Biomechanics Arboreal habitats pose numerous mechanical challenges to animals moving in them, which have been solved in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Caribbean Sea, and to the south and west by the Pacific Ocean. The region includes Middle America (Americas), Middle America (comprising the Caribbean, Central America, and Mexico) and Northern America. North America covers an area of about , representing approximately 16.5% of Earth's land area and 4.8% of its total surface area. It is the third-largest continent by size after Asia and Africa, and the list of continents and continental subregions by population, fourth-largest continent by population after Asia, Africa, and Europe. , North America's population was estimated as over 592 million people in list of sovereign states and dependent territories in North America, 23 independent states, or about 7.5% of the world's popula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraves
Paraves are a widespread group of theropod dinosaurs that originated in the Middle Jurassic period. In addition to the extinct dromaeosauridae, dromaeosaurids, troodontidae, troodontids, Anchiornithidae, anchiornithids, and possibly the scansoriopterygidae, scansoriopterygids, the group also contains the Avialae, avialans, which include diverse extinct taxa as well as the over 11,000 species of living birds. Basal members of Paraves are well known for the possession of an enlarged claw on the second digit of the foot, which was held off the ground when walking in some species. A number of differing scientific interpretations of the relationships between paravian taxa exist. New fossil discoveries and analyses make the classification of Paraves an active subject of research. Description Like other theropods, all paravians are bipedal, walking on their two hind legs. The teeth of basal paravians were curved and serrated, but not blade-like except in some specialized species, suc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Korea
South Korea, officially the Republic of Korea (ROK), is a country in East Asia. It constitutes the southern half of the Korea, Korean Peninsula and borders North Korea along the Korean Demilitarized Zone, with the Yellow Sea to the west and the Sea of Japan to the east. Like North Korea, South Korea claims to be the sole legitimate government of the entire peninsula and List of islands of South Korea, adjacent islands. It has Demographics of South Korea, a population of about 52 million, of which half live in the Seoul Metropolitan Area, the List of largest cities, ninth most populous metropolitan area in the world; other major cities include Busan, Daegu, and Incheon. The Korean Peninsula was inhabited as early as the Lower Paleolithic period. Gojoseon, Its first kingdom was noted in Chinese records in the early seventh century BC. From the mid first century BC, various Polity, polities consolidated into the rival Three Kingdoms of Korea, kingdoms of Goguryeo, Baekje, and Sil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jinju Formation
The Jinju Formation (), also known as the Dongmyeong Formation () in some literature is an Early Cretaceous geologic Formation (geology), formation in South Korea.Jinju Formation in the Paleobiology Database Dinosaur remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus. The depositional age of this formation spans from approximately 112.4 ± 1.3 to 106.5 million years ago (early Albian) based on detrital zircon U-Pb dating. It predominantly consists of black shale, with sandstone packets, deposited in a fluvial-lacustrine setting. A diverse Arthropoda, arthropod fauna, including freshwater arthropods, spiders, and insects, is known from the formation. Other notable fossils known from the formation include seve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
