The Ultimate Dinosaur Encyclopedia

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In 2016, the estimated number of dinosaur species that existed in the Mesozoic was 1,543–2,468. [25] [26] In 2021, the number of modern-day birds (avian dinosaurs) was estimated to be at 10,806 species. [27] Some are herbivorous, others carnivorous, including seed-eaters, fish-eaters, insectivores, and omnivores. While dinosaurs were ancestrally bipedal (as are all modern birds), some prehistoric species were quadrupeds, and others, such as Anchisaurus and Iguanodon, could walk just as easily on two or four legs. Cranial modifications like horns and crests are common dinosaurian traits, and some extinct species had bony armor. Although known for large size, many Mesozoic dinosaurs were human-sized or smaller, and modern birds are generally small in size. Dinosaurs today inhabit every continent, and fossils show that they had achieved global distribution by at least the Early Jurassic epoch. [28] Modern birds inhabit most available habitats, from terrestrial to marine, and there is evidence that some non-avian dinosaurs (such as Microraptor) could fly or at least glide, and others, such as spinosaurids, had semiaquatic habits. [29] Distinguishing anatomical features Russell, Dale A. (1995). "China and the lost worlds of the dinosaurian era". Historical Biology. Milton Park, Oxfordshire: Taylor & Francis. 10 (1): 3–12. doi: 10.1080/10292389509380510. ISSN 0891-2963. Plot, Robert (1677). The Natural History of Oxford-shire: Being an Essay toward the Natural History of England. LCCN 11004267. OCLC 933062622 . Retrieved November 13, 2019. {{ cite book}}: |work= ignored ( help) The earliest confirmed dinosaur fossils include the saurischian ('lizard-hipped') dinosaurs Herrerasaurus 230–220mya, Staurikosaurus possibly 230–225mya, Eoraptor 231.4mya, [14] and Alwalkeria 230–220mya. Saturnalia, 232–225mya, may be a basal saurischian or a prosauropod. The others are basal saurischians.

The Archosaurs evolved into two main clades: those related to crocodiles, and those related to dinosaurs. Main article: Dinosaur renaissance John Ostrom's original restoration of Deinonychus, published in 1969 a b c Taylor, M.P. (2010). "Sauropod dinosaur research: a historical review". Geological Society, London, Special Publications. 343 (1): 361–386. Bibcode: 2010GSLSP.343..361T. doi: 10.1144/SP343.22. S2CID 910635. It's the perfect beginner's reference book for children aged 7-9 who are curious about all things dinosaurs.Mayr, Gerald (2009). Paleogene Fossil Birds. Berlin: Springer-Verlag. doi: 10.1007/978-3-540-89628-9. ISBN 978-3-540-89627-2. LCCN 2008940962. OCLC 916182693. S2CID 88941254 . Retrieved October 30, 2019. Dinosaurs diverged from their archosaur ancestors during the Middle to Late Triassic epochs, roughly 20million years after the devastating Permian–Triassic extinction event wiped out an estimated 96% of all marine species and 70% of terrestrial vertebrate species approximately 252million years ago. [104] [105] The oldest dinosaur fossils known from substantial remains date to the Carnian epoch of the Triassic period and have been found primarily in the Ischigualasto and Santa Maria Formations of Argentina, and the Pebbly Arkose Formation of Zimbabwe. [106] a b Brett-Surman, M. K.; Holtz, Thomas R.; Farlow, James O. (June 27, 2012). The Complete Dinosaur. Indiana University Press. p.25. ISBN 978-0-253-00849-7. When dinosaurs appeared, they were not the dominant terrestrial animals. The terrestrial habitats were occupied by various types of archosauromorphs and therapsids, like cynodonts and rhynchosaurs. Their main competitors were the pseudosuchians, such as aetosaurs, ornithosuchids and rauisuchians, which were more successful than the dinosaurs. [118] Most of these other animals became extinct in the Triassic, in one of two events. First, at about 215million years ago, a variety of basal archosauromorphs, including the protorosaurs, became extinct. This was followed by the Triassic–Jurassic extinction event (about 201million years ago), that saw the end of most of the other groups of early archosaurs, like aetosaurs, ornithosuchids, phytosaurs, and rauisuchians. Rhynchosaurs and dicynodonts survived (at least in some areas) at least as late as early –mid Norian and late Norian or earliest Rhaetian stages, respectively, [119] [120] and the exact date of their extinction is uncertain. These losses left behind a land fauna of crocodylomorphs, dinosaurs, mammals, pterosaurians, and turtles. [10] The first few lines of early dinosaurs diversified through the Carnian and Norian stages of the Triassic, possibly by occupying the niches of the groups that became extinct. [12] Also notably, there was a heightened rate of extinction during the Carnian pluvial event. [121] Evolution and paleobiogeography The supercontinent Pangaea in the early Mesozoic (around 200 million years ago) Cashmore, D.D.; Butler, R.J. (2019). "Skeletal completeness of the non-avian theropod dinosaur fossil record". Palaeontology. 62 (6): 951–981. doi: 10.1111/pala.12436. S2CID 197571209.

Dodson, Peter; Gingerich, Philip D., eds. (1993). "Functional Morphology and Evolution". The American Journal of Science and Arts. A special volume of the American Journal of Science. New Haven, CT: Kline Geology Laboratory, Yale University. 293-A. ISSN 0002-9599. OCLC 27781160. Holmes, Thom (1998). Fossil Feud: The Rivalry of the First American Dinosaur Hunters. Parsippany, NJ: Julian Messner. ISBN 978-0-382-39149-1. LCCN 96013610. OCLC 34472600. Apex of a deltopectoral crest (a projection on which the deltopectoral muscles attach) located at or more than 30% down the length of the humerus (upper arm bone)

Public enthusiasm for dinosaurs first developed in Victorian England, where in 1854, three decades after the first scientific descriptions of dinosaur remains, a menagerie of lifelike dinosaur sculptures was unveiled in London's Crystal Palace Park. The Crystal Palace dinosaurs proved so popular that a strong market in smaller replicas soon developed. In subsequent decades, dinosaur exhibits opened at parks and museums around the world, ensuring that successive generations would be introduced to the animals in an immersive and exciting way. [330] The enduring popularity of dinosaurs, in its turn, has resulted in significant public funding for dinosaur science, and has frequently spurred new discoveries. In the United States, for example, the competition between museums for public attention led directly to the Bone Wars of the 1880s and 1890s, during which a pair of feuding paleontologists made enormous scientific contributions. [331] Books about dinosaurs have been popular, especially with children, but adults have also enjoyed these kinds of books. In Edwardian times, Arthur Conan Doyle wrote a novel about a plateau filled with dinosaurs which he called The Lost World. Feathers are one of the most recognizable characteristics of modern birds, and a trait that was also shared by several non-avian dinosaurs. Based on the current distribution of fossil evidence, it appears that feathers were an ancestral dinosaurian trait, though one that may have been selectively lost in some species. [246] Direct fossil evidence of feathers or feather-like structures has been discovered in a diverse array of species in many non-avian dinosaur groups, [70] both among saurischians and ornithischians. Simple, branched, feather-like structures are known from heterodontosaurids, primitive neornithischians, [247] and theropods, [248] and primitive ceratopsians. Evidence for true, vaned feathers similar to the flight feathers of modern birds has been found only in the theropod subgroup Maniraptora, which includes oviraptorosaurs, troodontids, dromaeosaurids, and birds. [14] [249] Feather-like structures known as pycnofibres have also been found in pterosaurs. [250]