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''Altispinax'' (; "with high spines") is a genus of large predatory theropod dinosaur from the Early Cretaceous (Barremian) Obernkirchen Sandstein of Niedersachsen, Germany. It is only known from a single tooth. Material has also been referred to it from the Hastings Beds (Valanginian), Purbeck Beds (Early Cretaceous), and Lower Greensand (Aptian) of England, and the Weald Clay (Hauterivian-Barremian) of England and Belgium, but this material probably does not belong to ''Altispinax''.〔http://archosaur.us/theropoddatabase/Neotheropoda.htm#Altispinaxdunkeri〕〔http://www.dinodata.org/index.php?option=com_content&task=view&id=6014&Itemid=67〕 Three back vertebrae with high spines, earlier usually associated with ''Altispinax'' and the reason for its name, have later been named as the separate genus ''Becklespinax''. Its type species, ''Megalosaurus dunkeri'', was originally named and described by Wilhelm Barnim Dames on 16 December 1884 during a lecture.〔Dames, W.B. (1885). "Vorlegung eines Zahnes von ''Megalosaurus'' aus den Wealden des Deisters", ''Sitzungsberichte der Gesellschaft naturforschender Freunde zu Berlin, Jahrbuch 1884'', 36: 186-188〕 A synopsis of the lecture was actually published in 1885, but because this was in the form of an 1884 yearbook, the latter date is usually given. However, some sources indicate 1887 as the year of publication and designate the species as a ''Megalosaurus dunkeri'' Dames vide Koken 1887, because in that year, the type specimen, a single tooth, was again described and also illustrated in a publication by Ernst Koken.〔Koken, E. (1887). "Die Dinosaurier, Crocodiliden und Sauropterygier des Norddeutschen Wealden" (dinosaurians, crocodylids and sauropterygians of the North German Wealden ), In: ''Geologisch-Palaeontologische Abhandlungen'' 3(5): 311-419.〕 The specific name honours paleontologist Wilhelm Dunker, who, many years earlier, had discovered the tooth on the Deister, in the main coal seam of Obernkirchen. This holotype had been, under the inventory number UM 84, added by him to the collection of the University of Marburg.〔 In 1888, Richard Lydekker redescribed many fragmentary specimens from the Cretaceous of England which previously had been assigned to ''Megalosaurus bucklandii''. Because the latter is a Jurassic species, he referred them to the Cretaceous ''Megalosaurus dunkeri'',〔Lydekker, R. (1888). ''Catalogue of the Fossil Reptilia and Amphibia in the British Museum (Natural History), Cromwell Road, S.W., Part 1. Containing the Orders Ornithosauria, Crocodilia, Dinosauria, Squamata, Rhynchocephalia, and Proterosauria''. British Museum of Natural History, London, 309 pages.〕 which thus generally became to be understood as a British Early Cretaceous theropod. In 1923, Friedrich von Huene created a separate genus for ''Megalosaurus dunkeri'': ''Altispinax''. The generic name is derived from Latin "''altus''" meaning "high" and Neolatin "''spinax''", as "with spines". The name was inspired by specimen BMNH R1828, a series of three dorsal vertebrae with very high spines that von Huene referred to the species. Although implicitly the new combination name of the type species ''Megalosaurus dunkeri'' was ''Altispinax dunkeri'', this combination does not occur in the 1923 publication.〔Huene, F. von (1923). "Carnivorous Saurischia in Europe since the Triassic". ''Bulletin of the Geological Society of America'', 34: 449-458.〕 The first to actually use it was Oskar Kuhn in 1939.〔Kuhn, O. (1939). ''Saurischia — Fossilium catalogus I, Animalia, Pars 87''. 's-Gravenhage, W. Junk, 1939, 124 pages.〕 Contrary to normal practice, von Huene in 1926 again named ''Altispinax'' based on the vertebrae, on the condition they could be shown to belong to the ''Megalosaurus dunkeri'' material.〔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.〕 Such a second naming act is invalid, however. After 1926, ''Altispinax'' was usually seen as a British dinosaur with a high sail on its back. However, later in the twentieth century it was realised that the German type specimen, the tooth, was undiagnostic, making ''Altispinax'' a ''nomen dubium'' with no provable connection to the spines. In 1988 Gregory S. Paul created a separate species for the vertebrae series, that he assigned to ''Acrocanthosaurus'' as an ''Acrocanthosaurus? altispinax''.〔Paul, G.S., 1988, ''Predatory Dinosaurs of the World''. Simon & Schuster, New York 464 pp〕 As already indicated by the question mark, Paul himself considered this designation to be tentative. Therefore, in 1991 George Olshevsky named a separate genus ''Becklespinax'' for the spined vertebrae.〔Olshevsky, G. (1991). ''A revision of the parainfraclass Archosauria Cope, 1869, excluding the advanced Crocodylia. Mesozoic Meanderings 2'', 196 pp.〕 Four other species would be named within the genus ''Altispinax''. In 1923 von Huene renamed ''Megalosaurus oweni'' Lydekker 1889, based on the metatarsus BMNH R2559, into ''Altispinax oweni''.〔 In 1991 Olshevsky created a separate genus ''Valdoraptor'' for this species.〔 In 1932 von Huene renamed ''Megalosaurus parkeri'' Huene 1923 into ''Altispinax parkeri''.〔Huene, F. von (1932). ''Die fossile Reptil-Ordnung Saurischia, ihre Entwicklung und Geschichte''. Monographien zur Geologie und Palaeontologie, Series 1, vol. 4(1-2), 361 pages〕 This species in 1964 was given the separate generic name ''Metriacanthosaurus''. In 2000, Oliver Walter Mischa Rauhut, assuming the 1923 naming by von Huene was invalid because the combination ''Altispinax dunkeri'' had not been mentioned, considered the 1926 naming to be valid and to pertain only to the vertebrae. The name ''Becklespinax'' would then be redundant and the name ''Altispinax'' could be maintained with the new combination name ''Altispinax altispinax'' for the vertebrae.〔Rauhut, O.W.M. (2000). ''The interrelationships and evolution of basal theropods (Dinosauria, Saurischia)''. Ph.D. dissertation, University of Bristol, 440 pp.〕 This name is thus a junior objective synonym of ''Becklespinax''. The same is true for ''Altispinax lydekkerhueneorum'', a ''nomen nudum'' in 1995 used by S. Pickering for the vertebrae.〔Pickering, S. (1995). ''Jurassic Park: Unauthorized Jewish Fractals in Philopatry, A Fractal Scaling in Dinosaurology Project'', 2nd revised printing, Capitola, California, 478 pp.〕 The only fossil that can be reliably assigned to the ''Altispinax'' material, the original tooth, consists of a crown with a length of six centimetres and a base length of twenty-two millimetres. It is moderately recurved with serrations on its back edge running all the way to the base. Dames concluded that there were two traits in which the tooth of ''M. dunkeri'' differed from that of ''M. bucklandii'': the lack of serrations on the front edge and the flatter cross-section.〔 However, already Lydekker pointed out that the serrations could have been worn off, and the greater flatness could have been caused by a compression of the fossil. ==References== 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「Altispinax」の詳細全文を読む スポンサード リンク
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