Dinosauros emplumados

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Impresión de Anchiornis , ilustrando as cores e disposición das plumas

Os dinosauros emplumados considéranse fósiles de transición entre dinosauros clásicos e aves. Era xa coñecido que as aves antigas como o Archaeopteryx tiñan moitas características de réptil, como dentes, e poutas nas súas dedas, e moitos anos antes teorizárase que os paxaros descendían de dinosauros terópodos. A finais dos anos 1990, os descubrimentos de dinosauros emplumados en China achegaron a proba concluínte da conexión, aínda que os detalles xenealóxicos aínda estean a ser dilucidados. Demostrouse de moitos xeitos a relación de descendencia entre aves e dinosauros, xa que a súa similitude morfolóxica en canto ao cranio, a cadeira, as patas e as extremidades superiores é moi notable. As aves son claramente monofiléticas e os seus primeiros representantes atópanse no Xurásico (Protoavis, un fósil controvertido do finais do Triásico, é considerado non aviano pola maioría dos paleontólogos).

Xéneros de dinosauros emplumados[editar | editar a fonte]

Dende 1996 até hoxe describíronse 21 xéneros de dinosauros non avianos con plumas ou protoplumas preservadas nos seus fósiles:

  1. Avimimus* (1987)[1][2]
  2. Sinosauropteryx (1996)[3]
  3. Protarchaeopteryx (1997)[4]
  4. Caudipteryx (1998)[5]
  5. Rahonavis* (1998)[6]
  6. Shuvuuia* (1999)[7]
  7. Sinornithosaurus (1999)[8]
  8. Beipiaosaurus (1999)[9]
  9. Microraptor (2000)[10]
  10. Nomingia* (2000)[11]
  11. Cryptovolans (2002)[12]
  12. Scansoriopteryx (2002)[13]
  13. Epidendrosaurus (2002)[14]
  14. Yixianosaurus (2003)[15]
  15. Dilong (2004)[16]
  16. Pedopenna (2005)[17]
  17. Jinfengopteryx (2005)[18][19]
  18. Sinocalliopteryx (2007)[20]
  19. Velociraptor* (2007)[21]
  20. Epidexipteryx (2008)[22]
  21. Anchiornis (2009)[23]

Notas[editar | editar a fonte]

  1. Kurzanov, S.M. (1987). "Avimimidae and the problem of the origin of birds." Transactions of the Joint Soviet-Mongolian Paleontological Expedition, 31: 5-92. [in Russian]
  2. Chiappe, L.M. and Witmer, L.M. (2002). Mesozoic Birds: Above the Heads of Dinosaurs. Berkeley: University of California Press, 536 pp. ISBN 0-520-20094-2
  3. Ji, Q., and Ji, S. (1996). "On discovery of the earliest bird fossil in China and the origin of birds." Chinese Geology 10 (233): 30-33.
  4. Ji, Q., and Ji, S. (1997). "A Chinese archaeopterygian, Protarchaeopteryx gen. nov." Geological Science and Technology (Di Zhi Ke Ji), 238: 38-41. Translated By Will Downs Bilby Research Center Northern Arizona University January, 2001
  5. Qiang, J., .Currie, P.J., Norell., M.A. & Shu-An, J., 1998. Two feathered dinosaursfrom northeastern China. Nature 393 753-761.
  6. "The Theropod Ancestry of Birds: New Evidence from the Late Cretaceous of Madagascar". Science (5358).. doi 10.1126/science.279.5358.1915 (HTML abstract)
  7. Schweitzer, Mary Higby, Watt, J.A., Avci, R., Knapp, L., Chiappe, L, Norell, Mark A., Marshall, M. (1999). "Beta-Keratin Specific Immunological reactivity in Feather-Like Structures of the Cretaceous Alvarezsaurid, Shuvuuia deserti Journal of Experimental Biology (Mol Dev Evol) 255:146-157
  8. Xu, X., Wang, X., Wu, X., 1999. A dromaeosaurid dinosaur with a filamentous integument from the Yixian Formation of China. Nature 401:6750 262-266 doi 10.1038/45769
  9. Xu. X., Zhao, X., Clark, J.M., 1999. A new therizinosaur from the Lower Jurassic lower Lufeng Formation of Yunnan, China. Journal of Vertebrate Paleontology 21:3 477–483 doi 10.1671/0272-4634
  10. Xu, X., Zhou, Z., and Wang, X. (2000). "The smallest known non-avian theropod dinosaur." Nature, 408 (December): 705-708.[1]
  11. Barsbold, R., Osmólska, H., Watabe, M., Currie, P.J., and Tsogtbaatar, K. (2000). "New Oviraptorosaur (Dinosauria, Theropoda) From Mongolia: The First Dinosaur With A Pygostyle". Acta Palaeontologica Polonica, 45(2): 97-106.
  12. Czerkas, S.A., Zhang, D., Li, J., and Li, Y.. "Flying Dromaeosaurs". Feathered Dinosaurs and the Origin of Flight: The Dinosaur Museum Journal 1. Czerkas, S.J..
  13. Czerkas, S.A., and Yuan, C. (2002). "An arboreal maniraptoran from northeast China." Pp. 63-95 in Czerkas, S.J. (Ed.), Feathered Dinosaurs and the Origin of Flight. The Dinosaur Museum Journal 1. The Dinosaur Museum, Blanding, U.S.A. PDF abridged version
  14. Zhang, F., Zhou, Z., Xu, X. & Wang, X. (2002). "A juvenile coelurosaurian theropod from China indicates arboreal habits." Naturwissenschaften, 89(9): 394-398. doi=10.1007 /s00114-002-0353-8.
  15. Xu, X. and Wang, X.-L. (2003). "A new maniraptoran from the Early Cretaceous Yixian Formation of western Liaoning." Vertebrata PalAsiatica, 41(3): 195–202.
  16. Xu, X., Norell, M. A., Kuang, X., Wang, X., Zhao, Q., Jia, C.. "Basal tyrannosauroids from China and evidence for protofeathers in tyrannosauroids". Nature. DOI:10.1038/nature02855.
  17. Xu, X., and Zhang, F. (2005). "A new maniraptoran dinosaur from China with long feathers on the metatarsus." Naturwissenschaften, 92(4): 173 - 177.
  18. Ji, Q., Ji, S., Lu, J., You, H., Chen, W., Liu, Y., and Liu, Y. (2005). "First avialan bird from China (Jinfengopteryx elegans gen. et sp. nov.)." Geological Bulletin of China, 24(3): 197-205.
  19. "A basal dromaeosaurid and size evolution preceding avian flight" (pdf). Science. DOI:10.1126/science.1144066. PMID 17823350. http://www.sciencemag.org/cgi/reprint/317/5843/1378.pdf.
  20. Ji, S., Ji, Q., Lu J., and Yuan, C. (2007). "A new giant compsognathid dinosaur with long filamentous integuments from Lower Cretaceous of Northeastern China." Acta Geologica Sinica, 81(1): 8-15.
  21. "Feather quill knobs in the dinosaur Velociraptor" (pdf). Science (5845). DOI:10.1126/science.1145076. PMID 17885130. http://www.sciencemag.org/cgi/reprint/317/5845/1721.pdf.
  22. Zhang, F., Zhou, Z., Xu, X., Wang, X., & Sullivan, C. (2008). "A bizarre Jurassic maniraptoran from China with elongate ribbon-like feathers." Available from Nature Precedings, doi:10.1038/npre.2008.2326.1 [2].
  23. Xu, X., Zhao, Q., Norell, M., Sullivan, C., Hone, D., Erickson, G., Wang, X., Han, F. and Guo, Y. (in press). "A new feathered maniraptoran dinosaur fossil that fills a morphological gap in avian origin." Chinese Science Bulletin, 6 pages, accepted November 15, 2008.