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Caenagnathoidea ("recent jaw forms") is a group of advanced oviraptorosaurian dinosaurs from the Cretaceous Period of what are now Asia and North America. They are distinct for their characteristically short, beaked, parrot-like skulls, often with bony crests atop the head. They ranged in size from ''Caudipteryx'', which was the size of a turkey, to the 8 meter long, 1.4 ton ''Gigantoraptor''.〔Xu, X., Tan, Q., Wang, J., Zhao, X., and Tan, L. (2007). "A gigantic bird-like dinosaur from the Late Cretaceous of China." ''Nature'', 447: 844-847.〕 The group (along with all maniraptoran dinosaurs) is close to the ancestry of birds. The most complete specimens have been found in Asia, representing members of the sub-group Oviraptorinae.〔 Notable but fragmentary remains are also known from North America, almost all of which belong to the subgroup Elmisaurinae.〔Varricchio, D. J. 2001. Late Cretaceous oviraptorosaur (Theropoda) dinosaurs from Montana. pp. 42–57 in D. H. Tanke and K. Carpenter (eds.), Mesozoic Vertebrate Life. Indiana University Press, Indianapolis, Indiana.〕 The earliest definitive caenangnathoid is ''Microvenator celer'', which dates to the late Aptian age of the early Cretaceous period, though the slightly earlier ''Caudipteryx'' from the lower Yixian Formation of China, may also be a member of this group. ==Classification== The internal classification of the oviraptorosaurs has also been controversial. Most early studies divided them into two primary sub-groups, the Caenagnathidae and the Oviraptoridae. The Oviraptoridae was further divided into the small, short-armed, and crestless subfamily Ingeniinae, and the larger, crested, long-armed Oviraptorinae. However, later phylogenetic studies showed that many traditional members of the Caenagnathidae were in fact more closely related to the crested oviraptorids. Because ''Caenagnathus'' itself is no longer considered part of this group, the subfamily is usually now termed the Elmisaurinae. The taxonomy here follows the one presented by Thomas Holtz, Jr. in 2010 unless otherwise noted.〔Holtz, Thomas R. Jr. (2010) ''Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages,'' (Winter 2010 Appendix. )〕 The following cladogram follows an analysis by Phil Senter, 2007.〔Senter, P. (2007). "A new look at the phylogeny of Coelurosauria (Dinosauria: Theropoda)." ''Journal of Systematic Palaeontology'', ().〕 }} |label3=Ingeniinae |3= }} }} }} }} 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「Caenagnathoidea」の詳細全文を読む スポンサード リンク
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