|
''Changchengornis'' is an extinct basal bird genus from the Early Cretaceous. Its remains have been found in the People's Republic of China, in Chaomidianzi Formation rocks from around the Barremian-Aptian boundary, deposited 125 million years ago. In 1998 Ji Shuan and Luis Chiappe discovered among the many specimens of the National Geological Museum of China at Beijing assigned to ''Confuciusornis'', an exemplar that seemed somewhat different. Subsequent preparation by the American Museum of Natural History showed that it indeed was a separate species, new to science. In 1999 Ji, Chiappe and Ji Qiang named the type species and only species of ''Changchengornis'': ''Changchengornis hengdaoziensis''. The generic name refers to the Great Wall of China, ''changcheng'', and combines this with a Greek ὄρνις, ''ornis'', "bird". The specific name refers to the geological Hengdaozi Member.〔Ji Q., Chiappe, L. and Ji S., 1999, "A new Late Mesozoic confuciusornithid bird from China", ''Journal of Vertebrate Paleontology'' 19(1): 1-7〕 The holotype specimen, GMV-2129, was found near the village of Jianshangou in Liaoning province, in the Jianshangou Beds of the Hengdaozi Member of the Yixian Formation, at the time seen as a separate Chaomidianzi Formation. It consists of a plate and counterplate, GMV-2129a/b, showing a largely complete and articulated but compressed and somewhat damaged skeleton. Much of the feathering has been preserved in an excellent state of preservation. ''Changchengornis'' resembles its relative ''Confuciusornis''.〔Chiappe, Luis M., Shu-An, Ji, Qiang, Ji, Norell, Mark A., 1999, "Anatomy and systematics of the Confuciusornithidae (Theropoda:Aves) from the Late Mesozoic of northeastern China", ''Bulletin of the American museum of Natural History'' N°242 89 pp〕 The type specimen is rather small, not larger than the smallest known specimens of ''Confuciusornis''. Compared to the latter, ''Changchengornis'' had a beak that was more pointed, slightly hooked at the tip, proportionally shorter, and higher at the back.〔Mortimer, Michael (2004): The Theropod Database: (Phylogeny of taxa ). Retrieved 2013-MAR-02.)〕 The deltopectoral crest of the humerus is not pierced. GMV-2129 also shows two elongated, ribbon-like tail feathers as found in some specimens of ''Confuciusornis'', that are often considered to be the males. Also, the fossil gives the impression of a head tuft or crest being present; if so, the outline of its head must have borne an uncanny resemblance to today's ''Tauraco'' or turacos in general but it could also be an artefact of conservation. ''Changchengornis'' was a close relative of the better-known ''Confuciusornis''. In 1999 it was assigned to the Confuciusornithidae. The more pointed bill of ''Changchengornis'' might indicate a diet different from that of ''Confuciusornis''. However, of ''Confuciusornis'' itself it is contested whether it were a fish eater, an omnivore, or a seed eater. ==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「Changchengornis」の詳細全文を読む スポンサード リンク
|