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''Tarchia'' (meaning "brainy one") is a genus of herbivorous ankylosaurid dinosaur from the late Cretaceous of Mongolia. ==Discovery and naming== In 1970, a Polish-Mongolian expedition discovered an ankylosaurian skull near Khulsan. In 1977, Teresa Maryańska named and described the type species ''Tarchia kielanae''. The generic name is derived from Mongolian ''tarkhi'', "brain" and Latin ''~ia'', in reference to a brain size presumed larger than that of the related form ''Saichania''. The specific name honours Professor Zofia Kielan-Jaworowska, the leader of the expedition. The holotype, ZPal MgD-I/111, was discovered in the Upper Cretaceous (possibly Campanian-Maastrichtian) Barun Goyot Formation (previously known as the 'Lower Nemegt Beds') of the Nemegt Basin of Mongolia. It consists of a skull roof, braincase and rear skull elements.〔Maryańska, T. 1977. "Ankylosauridae (Dinosauria) from Mongolia". ''Palaeontologia Polonica'' 37: 85-151〕 Maryańska referred three additional specimens: ZPAL MgDI/43, a large postcranial skeleton containing three "free" tail vertebrae, twelve tail vertebrae of the "handle" of the tail club and a scute; ZPAL MgDI/49, a right humerus; and PIN 3142/251, a skeleton with skull, that as yet remains undescribed. ''Tarchia'' is currently, with ''Saichania'', among the geologically youngest known of all the Asian ankylosaurid dinosaurs. In 1977, Tatyana Tumanova named a second species: ''Tarchia gigantea''. This was a renaming of ''Dyoplosaurus giganteus'' Maleev 1956, which had been based on specimen PIN 551/29.〔Tumanova, T. A. 1977. "New data on the ankylosaur ''Tarchia gigantea''", ''Paleontological Journal'' 11: 480-486〕 In 1987, Tumanova concluded that both species were identical. This would make ''Dyoplosaurus giganteus'' the senior synonym of ''Tarchia kielanae''.〔T.A. Tumanova, 1987, ''Pantsirnyye dinozavry Mongolii, Trudy Sovmestnaya Sovetsko-Mongol'skaya Paleontologicheskaya Ekspeditsiya 32'', 80 pp〕 This was generally accepted and ''Tarchia gigantea'' became the usual species name, as a ''combinatio nova'' replacing ''Tarchia kielanae''. However, recent study by Victoria Megan Arbour indicates that ''D. giganteus'' is indistinguishable from other ankylosaurs from the late Campanian-Maastrichtian of Mongolia, and hence a ''nomen dubium'', reviving ''Tarchia kielanae''.〔Arbour, Victoria Megan, 2014. ''Systematics, evolution, and biogeography of the ankylosaurid dinosaurs.'' Ph.D thesis, University of Alberta. https://era.library.ualberta.ca/public/.../Arbour_Victoria_Spring2014.pdf〕 A rump with tail and club, specimen ZPAL MgD I/113, once referred to ''Dyoplosaurus giganteus'' and subsequently to ''Tarchia gigantea'', was by Arbour seen as different from the ''D. giganteus'' holotype.〔Victoria M. Arbour, Nicolai L. Lech-Hernes, Tom E. Guldberg, Jørn H. Hurum, and Philip J. Currie, 2013, "An ankylosaurid dinosaur from Mongolia with in situ armour and keratinous scale impressions", ''Acta Palaeontologica Polonica'' 58(1): 55-64〕 The study by Arbour also concluded that specimen PIN 3142/250, in 1977 referred to ''Tarchia'' by Tumanova, probably belonged to ''Saichania'' instead. This would radically change the common image of ''Tarchia'' as this exemplar had been by far the best preserved and most illustrations, museum mounts and indeed scientific research had been based on it. Arbour discovered that the holotype of ''Tarchia'' shared distinguishing traits with that of ''Minotaurasaurus'' Miles & Miles 2009, concluding that the latter is a junior synonym of ''Tarchia''.〔Victoria M. Arbour, Philip J. Currie and Demchig Badamgarav, 2014, "The ankylosaurid dinosaurs of the Upper Cretaceous Baruungoyot and Nemegt formations of Mongolia", Zoological Journal of the Linnean Society 172(3): 631–652〕 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「Tarchia」の詳細全文を読む スポンサード リンク
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