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Darwinopterus
''Darwinopterus'' (meaning "Darwin's wing") is a genus of pterosaur, discovered in China and named after biologist Charles Darwin. Between 30 and 40 fossil specimens have been identified,〔 all collected from the Tiaojishan Formation, which dates to the middle Jurassic period, 161-160.5 Ma ago.〔Liu Y.-Q. Kuang H.-W., Jiang X.-J., Peng N., Xu H. & Sun H.-Y. (2012). "Timing of the earliest known feathered dinosaurs and transitional pterosaurs older than the Jehol Biota." ''Palaeogeography, Palaeoclimatology, Palaeoecology'' (advance online publication).〕 The type species, ''D. modularis'', was described in February 2010.〔Lü, J., Unwin, D.M., Jin, X., Liu, Y. and Ji, Q. (2010). "Evidence for modular evolution in a long-tailed pterosaur with a pterodactyloid skull." ''Proceedings of the Royal Society B'', 277(1680): 383-389. PMID 19828548〕 ''D. modularis'' was the first known pterosaur to display features of both long-tailed ('rhamphorhynchoid') and short-tailed (pterodactyloid) pterosaurs, and was described as a transitional fossil between the two groups.〔Dell'Amore, C. (2009). ("Odd New Pterosaur: 'Darwin's Wing' Fills Evolution Gap." ) ''National Geographic News'', 13 October 2009. Accessed 14 October 2009.〕 Two additional species, ''D. linglongtaensis'' and ''D. robustodens'', were described from the same fossil beds in December 2010 and June 2011, respectively.〔Lü, J., Xu, L., Chang, H. and Zhang, X. (2011). "A new darwinopterid pterosaur from the Middle Jurassic of western Liaoning, northeastern China and its ecological implications." ''Acta Geologica Sinica - English Edition'', 85(3): 507–514. 〕
==Description==
''Darwinopterus'', like its closest relatives, is characterized by its unique combination of basal and derived pterosaurian features. While it had a long tail and other features characteristic of the 'rhamphorhynchoids', it also had distinct pterodactyloid features, such as long vertebrae in the neck and a single skull opening in front of the eyes, the nasoantorbital fenestra (in most 'rhamphorhynchoids', the antorbital fenestra and the nasal opening are separate).〔
''Darwinopterus'' is distinguished from its close relatives by the greater relative length of the back portion of the skull compared to its jaws, thin nasal bone, and elongated hip bone (illium). The teeth in all species were spaced widely with the longest teeth at the jaw tips. The teeth were spike-like in form, and set into tooth sockets with raised margins. The hand bones were relatively short, even shorter than the femur. The tail was long, with over 20 vertebrae, and was partially stiffened by long, thin bony projections.〔 Unlike other wukongopterids, the head crest found in males was supported by a thin bony extension of the skull, with a serrated top edge. The serrations probably helped anchor an even larger keratin extension.〔
Specimens of ''Darwinopterus'' have been divided into three distinct species, based largely on the size and shape of their teeth. The first, ''D. modularis'', was named by Lü Junchang and colleagues in 2010. ''D. modularis'' had an especially elongated back end to the skull, and widely spaced, "spike-like" teeth. ''D. linglongtaensis'' was named by Wang Xiaolin and colleagues in later in 2010. It was characterized by a shorter and taller skull and shorter, cone-shaped teeth.〔 In 2011, Lü and another team of scientists described and named ''D. robustodens'', for a new specimen with very robust teeth. Lü and colleagues (2011) suggested that these differences in tooth shape may indicate that each ''Darwinopterus'' species occupied a different ecological niche, with the teeth of each becoming specialized for different food sources. The robust teeth of ''D. robustodens'', for example, may have been used to feed on hard-shelled beetles.〔
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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