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Dubreuillosaurus
''Dubreuillosaurus'' is a genus of carnivorous dinosaur from the middle Jurassic Period. It is a megalosaurid theropod. Its fossils were found in France. The only named species, ''Dubreuillosaurus valesdunensis'', was originally described as a species of ''Poekilopleuron'', ''Poekilopleuron? valesdunensis'', which is still formally the type species of the genus. It was later renamed ''Dubreuillosaurus valesdunensis'' when, in 2005, Allain came to the conclusion that it was not part of the genus ''Poekilopleuron''. Its type specimen, MNHN 1998-13, is only rivalled in the number of preserved elements in this group by that of ''Eustreptospondylus''. ''Dubreuillosaurus'' is considered to be the sister species of ''Magnosaurus''. It did not show signs of insular dwarfism even though it was uncovered on an island.
==Discovery and naming==
In 1994, the mayor of Conteville in Normandy, André Dubreuil, noted that during land rehabilitation of the old quarry of ''Pierre de Caen'', dinosaur bones had surfaced. He secured a partial skull and some ribs and notified the Paris ''Muséum national d'Histoire naturelle''. However, professional excavations only started in 1998 when the rock of the collapsed quarry face had already been spread by a bulldozer over a considerable surface. It proved necessary to dig up and sieve many cubic metres of rubble over several years, ultimately salvaging about two thousand bone fragments, varying in size between one and ten centimetres. From these scraps a more complete skeleton had to be reassembled.
In 2002, when this process had not yet been completed, Ronan Allain, after having dedicated a thesis to it,〔Allain, R., 2002, ''Les Megalosauridae (Dinosauria, Theropoda). Nouvelle découverte et révision systématique: Implications phylogénétiques et paléobiogéographiques''. Paris. Thesis, Muséum national d'histoire naturelle 329 pp〕 named the find as a new species of ''Poekilopleuron'': ''Poekilopleuron? valesdunensis''. The specific name referred to the nearby ancient battlefield of the Battle of Val-ès-Dunes, where William the Conqueror had in 1046 defeated his enemies. The naming paper also contained a description of the skull. The question mark after the generic name already indicated the assignment to ''Poekilopleuron'' was tentative. By 2005, Allain had come to the conclusion that the new species was not part of ''Poekilopleuron''. He therefore created the new genus name ''Dubreuillosaurus'' for this species, the name honouring the Dubreuil family. The type species of the genus is the original ''Poekilopleuron valesdunensis'', the ''combinatio nova'' is ''Dubreuillosaurus valesdunensis''. The 2005 paper also contained a description of the postcranial skeleton.〔Allain, R., 2005, "The postcranial anatomy of the megalosaur ''Dubreuillosaurus valesdunensis'' (Dinosauria Theropoda) from the Middle Jurassic of Normandy, France", ''Journal of Vertebrate Paleontology'' 25(4): 850–858〕
The holotype, MNHN 1998-13, has been uncovered in a layer of the Calcaire de Caen Formation dating from the middle Bathonian. It consists of a fragmentary skeleton with skull. Preserved parts include: the majority of the skull; the splenial and angular of the lower jaw, a natural mold of the surangular, two cervical vertebrae, cervical ribs, seven dorsals, ribs, gastralia, three sacrals, ten caudals, a chevron, a piece of the scapula, a claw of the hand, a partial thighbone, the upper part of a shinbone, a partial fibula, a fifth metatarsal and the first phalanx of the third toe. Considering the incompleteness of most other megalosaurids, this genus is exceptional in having a significant percentage of the skeleton been found. The type specimen of ''Dubreuillosaurus'' is in the number of preserved elements only rivalled in this group by that of ''Eustreptospondylus''. The holotype represents a subadult individual.〔
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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