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''Proceratosaurus'' is a genus of small-sized (~ long) carnivorous theropod dinosaur from the Middle Jurassic (Bathonian) of England.〔Holtz, Thomas R. Jr. (2008) ''Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages'' (Supplementary Information ) 〕 It was originally thought to be an ancestor of ''Ceratosaurus'', due to the similar small crest on its snout. Now, however, it is considered a coelurosaur, specifically one of the earliest known members of Tyrannosauroidea, the clade of basal relatives of the tyrannosaurs. The type specimen is held in the London Museum of Natural History and was recovered in 1910 at Minchinhampton while excavating for a reservoir.〔 ==Classification== Arthur Smith Woodward, who initially studied ''Proceratosaurus'', originally thought it to be an ancestor of the Late Jurassic ''Ceratosaurus'', due to the similarity of their nasal crests. Later study during the 1930s by Friedrich von Huene supported this interpretation, and Huene thought both dinosaurs represented members of the group Coelurosauria.〔von Huene, F. (1932). "Die fossile Reptil-Ordnung Saurischia, ihre Entwicklung und Geschichte." ''Monographien zur Geologie und Palaeontologie (Serie 1)'', 4: 1–361.〕 It was not until the late 1980s, after ''Ceratosaurus'' had been shown to be a much more primitive theropod and not a coelurosaur, that the classification of ''Proceratosaurus'' was again re-examined. Gregory S. Paul suggested that it was a close relative of ''Ornitholestes'', again mainly due to the crest on the nose (though the idea that ''Ornitholestes'' bore a nasal crest was later disproved). Paul considered both ''Proceratosaurus'' and ''Ornitholestes'' to be neither ceratosaurs nor coelurosaurs, but instead primitive allosauroids. Furthermore, Paul considered the much larger dinosaur ''Piveteausaurus'' to be the same genus as ''Proceratosaurus'', making ''Piveteausaurus'' a junior synonym. However, no overlapping bones between the two had yet been exposed from the rock around their fossils, and future study showed that they were indeed distinct.〔 Several phylogenetic studies in the early 21st century finally found ''Proceratosaurus'' (as well as ''Ornitholestes'') to be a coelurosaur, only distantly related to the ceratosaurids and allosauroids, though one opinion published in 2000 considered ''Proceratosaurus'' a ceratosaurid without presenting supporting evidence. Phylogenetic analyses by Thomas R. Holtz, Jr. in 2004 also placed ''Proceratosaurus'' among the coelurosaurs, though with only weak support, and again found an (also weakly supported) close relationship with ''Ornitholestes''.〔Rauhut, O.W.M., Milner, A.C. and Moore-Fay, S. (2010). "(Cranial osteology and phylogenetic position of the theropod dinosaur ''Proceratosaurus bradleyi'' (Woodward, 1910) from the Middle Jurassic of England )". ''Zoological Journal of the Linnean Society'', published online before print November 2009. 〕 The first major re-evaluation of ''Proceratosaurus'' and its relationships was published in 2010 by Oliver Rauhut and colleagues. Their study concluded that ''Proceratosaurus'' was in fact a coelurosaur, and moreover a tyrannosauroid, a member of the lineage leading to the giant tyrannosaurs of the Late Cretaceous. Furthermore, they found that ''Proceratosaurus'' was most closely related to the Chinese tyrannosauroid ''Guanlong''. They named the clade containing these two dinosaurs the Proceratosauridae, defined as all theropods closer to ''Proceratosaurus'' than to ''Tyrannosaurus'', ''Allosaurus'', ''Compsognathus'', ''Coelurus'', ''Ornithomimus'', or ''Deinonychus''.〔 Below is a cladogram by Loewen ''et al.'' in 2013. 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「Proceratosaurus」の詳細全文を読む スポンサード リンク
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