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Abelisauroidea
Abelisauroidea is typically regarded as a Cretaceous group, though the earliest abelisauridae remains are known from the Middle Jurassic of Argentina (classified as the species Eoabelisaurus mefi) and possibly Madagascar (fragmentary remains of an unnamed species) possible abelisauridae remains (an isolated left tibia, right femur, and right tibia) were also discovered in Late Jurassic Tendaguru Beds in Tanzania. Abelisauroids flourished in the Southern hemisphere during the Cretaceous period, but their origins can be traced back to at least the Middle Jurassic, when they had a more global distribution (the earliest known abelisauroid remains come from Australian and South American deposits dated to about 170 million years ago). By the Cretaceous period, abelisauroids had apparently become extinct in Asia and North America, possibly due to competition from tyrannosauroids. However, advanced abelisauroids of the family Abelisauridae persisted in the southern continents until the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ozraptor
''Ozraptor'' (meaning "Australian thief") is a genus of possibly abelisauroid theropod dinosaur from the Middle Jurassic (Bajocian) Colalura Sandstone of Australia, known from fragmentary remains. Discovery and naming In 1967 a group of four twelve-year-old Scotch College schoolboys found a fossil at the Bringo Railway Cutting site near Geraldton, which they showed to professor Rex Prider of the University of Western Australia. He had a cast made that he sent to experts of the British Museum of Natural History in London who thought it likely belonged to an extinct turtle. Re-evaluation of the bone in the 1990s after being prepared out of the rock by John Albert Long and Ralph Molnar classified the fossil as the shinbone of a genus of theropods.Long, J.A. (1998). ''Dinosaurs of Australia and New Zealand and other animals of the Mesozoic Era''. Harvard University Press, UNSW Press, pp 94-96. In 1998 Long and Molnar named and described the type (and only) species ''Ozraptor s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations containing land animal fossils include the Forest Marble Formation in England, the Kilmaluag Formation in Scotland,British Geological Survey. 2011Stratigraphic framework for the Middle Jurassic strata of Great Britain and the adjoining continental shelf: research report RR/11/06 British Geological Survey, Keyworth, Nottingham. the Daohugou Beds in China, the Itat Formation in Russia, and the Isalo III Formation of western Madagascar. Paleogeography During the Middle Jurassic Epoch, Pangaea began to separate into Laurasia and Gondwana, and the Atlantic Ocean formed. Eastern Laurasia was tectonically active as the Cimmerian plate continued to collide with Laurasia's southern coast, completely closing the Paleo-Tethys Ocean. A subd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, the fourth-largest country in the Americas, and the eighth-largest country in the world. It shares the bulk of the Southern Cone with Chile to the west, and is also bordered by Bolivia and Paraguay to the north, Brazil to the northeast, Uruguay and the South Atlantic Ocean to the east, and the Drake Passage to the south. Argentina is a federal state subdivided into twenty-three provinces, and one autonomous city, which is the federal capital and largest city of the nation, Buenos Aires. The provinces and the capital have their own constitutions, but exist under a federal system. Argentina claims sovereignty over the Falkland Islands, South Georgia and the South Sandwich Islands, and a part of Antarctica. The earliest recorded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eoabelisaurus
''Eoabelisaurus'' () is a genus of abelisaurid theropod dinosaur from the Lower Jurassic Cañadón Asfalto Formation of the Cañadón Asfalto Basin in Argentina, South America. The generic name combines a Greek ἠώς, (''eos''), "dawn", with the name ''Abelisaurus'', in reference to the fact it represents an early relative of the latter. Only one species is currently recognized, ''E. mefi''; the specific name honours the MEF, the Museo Paleontológico "Egidio Feruglio", where discoverer Diego Pol is active. It is characterized by reduced forelimb proportions that show primitive characteristics of the Abelisauridae family. Discovery and naming In 2009, Argentinian paleontologist Diego Pol discovered the skeleton of a theropod near the village of Cerro Cóndor in Chubut Province. The remains were found in the Jugo Loco locality that is placed in a series of fine beds of mudstone, marlstone, and limestone in the Cañadón Asfalto Formation. In 2012, based on these remains, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous–Paleogene Extinction Event
The Cretaceous–Paleogene (K–Pg) extinction event (also known as the Cretaceous–Tertiary extinction) was a sudden mass extinction of three-quarters of the plant and animal species on Earth, approximately 66 million years ago. With the exception of some ectothermic species such as sea turtles and crocodilians, no tetrapods weighing more than survived. It marked the end of the Cretaceous Period, and with it the Mesozoic era, while heralding the beginning of the Cenozoic era, which continues to this day. In the geologic record, the K–Pg event is marked by a thin layer of sediment called the K–Pg boundary, which can be found throughout the world in marine and terrestrial rocks. The boundary clay shows unusually high levels of the metal iridium, which is more common in asteroids than in the Earth's crust. As originally proposed in 1980 by a team of scientists led by Luis Alvarez and his son Walter, it is now generally thought that the K–Pg extinction was caused b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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