Dinosauros emplumados

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 na China achegaron a proba concluínte da conexión, aínda que os detalles xenealóxicos 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).

Impresión de Anchiornis, ilustrando as cores e disposición das plumas

Xéneros de dinosauros emplumados

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

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, xaneiro de 2001
5. Qiang, J., .Currie, P.J., Norell., M.A. & Shu-An, J., 1998. Two feathered dinosaursfrom northeastern China. Nature 393 753-761.
6. Forster, Catherine A.; Sampson, Scott D.; Chiappe, Luis M. & Krause, David W. (1998a). "The Theropod Ancestry of Birds: New Evidence from the Late Cretaceous of Madagascar". Science (5358): pp. 1915–1919.. 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 (decembro): 705-708. Arquivado 17 de decembro de 2008 en Wayback Machine.
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. (2002). "Flying Dromaeosaurs". En Czerkas, S.J. Feathered Dinosaurs and the Origin of Flight: The Dinosaur Museum Journal 1. Blanding: The Dinosaur Museum. pp. 16–26.
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. (2004). "Basal tyrannosauroids from China and evidence for protofeathers in tyrannosauroids". Nature 431: 680–684. 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. Turner, Alan H.; Pol, Diego; Clarke, Julia A.; Erickson, Gregory M.; and Norell, Mark (2007). "A basal dromaeosaurid and size evolution preceding avian flight" (pdf). Science 317: 1378–1381. PMID 17823350. doi:10.1126/science.1144066.
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. Turner, A.H.; Makovicky, P.J.; and Norell, M.A. (2007). "Feather quill knobs in the dinosaur Velociraptor" (pdf). Science 317 (5845): 1721. PMID 17885130. doi:10.1126/science.1145076.
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 .
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, consultado o 15 de novembro de 2008.

Véxase tamén

• Aves
• Dinosauros
• Extinción en masa

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