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''Eustreptospondylus'' ( ;〔 meaning "true ''Streptospondylus''") is a genus of megalosaurid dinosaur, from the Callovian stage of the Middle Jurassic period (some time between 165 and 161 million years ago) in southern England, at a time when Europe was a series of scattered islands (due to tectonic movement at the time which raised the sea-bed and flooded the lowland). It might have foraged on shorelines for carcasses and marine life. The main fossil of ''Eustreptospondylus'' was found in 1870. At first it was assigned to other genera. In 1964 it was made a separate genus. ''Eustreptospondylus'' was about six metres long as an adult. It was carnivorous, bipedal and had a slightly stiffened tail. It was a typical theropod, with powerful hind limbs, and small forelimbs. ==Discovery and naming== In 1870, workers at the Summertown Brick Pit, just north of Oxford, England, found the skeleton of a theropod. The remains were acquired by the local bookseller James Parker, who brought them to the attention of Oxford Professor John Phillips. Phillips described the bones in 1871, but did not name them.〔Phillips, J., 1871, ''Geology of Oxford and the Valley of the Thames''. 529 pp〕 At the time, the remains represented the most complete skeleton of a large theropod ever found. Eustreptospondylus is still the most complete of any large Jurassic European theropod. In 1890, the skeleton was bought by Oxford University, and Arthur Smith Woodward examined it and referred it to ''Megalosaurus bucklandi''. In 1905 and 1906 Baron Franz Nopcsa reassigned the skeleton to the species, ''Streptospondylus cuvieri'', which had been first described by Sir Richard Owen in 1842, based on a now lost vertebra from the Bathonian stage of the Jurassic period.〔Owen, R. (1842). "Report on British fossil reptiles". ''Report of the British Association for the Advancement of Science 11'': 60–204〕 The reason for this assignment was that the type species ''Streptospondylus altdorfensis'' from France, was a clearly related form, and Nopcsa decided to subsume all British material of this nature under a single ''Streptospondylus'' species, for which then the name ''S. cuvieri'' could not be avoided.〔Nopcsa, F., 1905, "Notes on British dinosaurs. Part III: ''Streptospondylus''", ''Geological Magazine'' 5: 289-293〕〔Nopcsa, F., 1906, "Zur Kenntnis des Genus ''Streptospondylus''", ''Beiträge zur Paläontologie und Geologie Österreich-Ungarns und des Orients: Mitteilungen des Geologischen und Paläontologischen Institutes der Universität Wien'' 19: 59-83〕 The assignment of a rather complete find to a species based on very poor remains was troublesome. This was compounded by German palaeontologist Friedrich von Huene, who sometime referred to the specimen as ''Streptospondylus cuvieri'' and at other times considered it a species of ''Megalosaurus'': ''Megalosaurus cuvieri''.〔Huene, F. von, 1926, "The carnivorous Saurischia in the Jura and Cretaceous formations, principally in Europe", ''Revista del Museo de La Plata'', 29: 1-167〕 In 1964, Alick Donald Walker clarified matters by erecting a separate genus and species for the Oxford specimen: ''Eustreptospondylus oxoniensis''. The holotype, OUM J13558, was recovered by W. Parker from claystone in a marine layer of the Stewartby Member of the Oxford Clay Formation, which dates to the Callovian stage of the Jurassic period, approximately 162 million years ago. It consists of a rather complete skeleton, with a skull which is missing elements including the nasal bones, the jugals, the rear ends of the lower jaws, the lower arms and the end of the tail. It represents a subadult individual. The only other specimen ever referred to ''Eustreptospondylus oxoniensis'' is OUMNH J.29775, a left ilium. The holotype was fully prepared and exhibited in 1924, in a rather erect position. In the early twenty-first century a new display changed this to a horizontal position of the body. In 2000, Oliver Walter Mischa Rauhut found that only minor differences in the hip bones — a more upward extending fusion of the "feet" of the pubic bones — make ''Eustreptospondylus'' different from a previously known megalosaurid called ''Magnosaurus'', and in 2003 he proposed that they should be the same genus, which would make the full species name ''Magnosaurus oxoniensis''. In 2010, Gregory S. Paul considered the species identical to ''Streptospondylus altdorfensis''.〔Paul, G.S., 2010, ''The Princeton Field Guide to Dinosaurs'', Princeton University Press p. 89〕 As only one skeleton has been found, ''Eustreptospondylus'' was probably a rare theropod.〔 The first detailed description of the ''Eustreptospondylus'' material was in 1906 by Nopcsa. A modern description was published in 2008 by Rudyard Sadleir e.a.〔R. Sadleir, P.M. Barrett and H.P. Powell, 2008, ''The anatomy and systematics of'' Eustreptospondylus oxoniensis, ''a theropod dinosaur from the Middle Jurassic of Oxfordshire, England'', Monograph of the Palaeontological Society, 160(627) 82 pp〕 In 1964, Walker also named a second species of ''Eustreptospondylus'': ''Eustreptospondylus divesensis'', based on a French find.〔 In 1977 this became the separate genus ''Piveteausaurus''. 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「Eustreptospondylus」の詳細全文を読む スポンサード リンク
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