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''Spinosaurus'' (meaning "spine lizard") is a genus of theropod dinosaur that lived in what now is North Africa, during the lower Albian to lower Cenomanian stages of the Cretaceous period, about 112 to 97 million years ago. This genus was known first from Egyptian remains discovered in 1912 and described by German paleontologist Ernst Stromer in 1915. The original remains were destroyed in World War II, but additional material has come to light in recent years. It is unclear whether one or two species are represented in the fossils reported in the scientific literature. The best known species is ''S. aegyptiacus'' from Egypt, although a potential second species, ''S. maroccanus'', has been recovered from Morocco. ''Spinosaurus'' was among the largest of all known carnivorous dinosaurs, possibly larger than ''Tyrannosaurus'' and ''Giganotosaurus''. Estimates published in 2005, 2007, and 2008 suggested that it was between in length and in weight.〔Holtz, Thomas R. Jr. (2012) ''Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages,'' (Winter 2011 Appendix. )〕 A new estimate published in 2014 and based on a more complete specimen, supported the earlier research, finding that ''Spinosaurus'' could reach lengths greater than .〔 (Supplementary Information )〕 The skull of ''Spinosaurus'' was long and narrow, similar to that of a modern crocodilian. ''Spinosaurus'' is known to have eaten fish, and most scientists believe that it hunted both terrestrial and aquatic prey; evidence suggests that it lived both on land and in water as a modern crocodilian does. The distinctive spines of ''Spinosaurus'', which were long extensions of the vertebrae, grew to at least long and were likely to have had skin connecting them, forming a sail-like structure, although some authors have suggested that the spines were covered in fat and formed a hump. Multiple functions have been put forward for this structure, including thermoregulation and display. ==Description== Since its discovery, ''Spinosaurus'' has been a contender for the longest and largest theropod dinosaur.〔(nationalgeographic.com 'River Monster': 50-Foot Spinosaurus )〕 Both Friedrich von Huene in 1926 and Donald F. Glut in 1982 listed it as among the most massive theropods in their surveys, at in length and upwards of in weight. In 1988, Gregory Paul also listed it as the longest theropod at , but gave a lower mass estimate of .〔 Dal Sasso ''et al''. (2005) assumed that ''Spinosaurus'' and ''Suchomimus'' had the same body proportions in relation to their skull lengths, and thereby calculated that ''Spinosaurus'' was in length and in weight. The Dal Sasso ''et al''. estimates were criticized because the skull length estimate was uncertain, and (assuming that body mass increases as the cube of body length) scaling ''Suchomimus'' which was long and in mass to the range of estimated lengths of ''Spinosaurus'' would produce an estimated body mass of . François Therrien and Donald Henderson, in a 2007 paper using scaling based on skull length, challenged previous estimates of the size of ''Spinosaurus'', finding the length too great and the weight too small.〔 Based on estimated skull lengths of , their estimates include a body length of and a body mass of .〔 The lower estimates for ''Spinosaurus'' would imply that the animal was shorter and lighter than ''Carcharodontosaurus'' and ''Giganotosaurus''.〔 The Therrien and Henderson study has been criticized for the choice of theropods used for comparison (e.g., most of the theropods used to set the initial equations were tyrannosaurids and carnosaurs, which have a different build than spinosaurids), and for the assumption that the ''Spinosaurus'' skull could be as little as in length. Improvement of the precision of size estimates for ''Spinosaurus'' requires the discovery of more complete remains as available for some other dinosaurs, especially the limb bones of ''Spinosaurus'' which are "hitherto unknown".〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Spinosaurus」の詳細全文を読む スポンサード リンク
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