Caudipteryx 672390 221740941 2008-06-25T21:51:09Z CommonsDelinker 2304267 Removing "Caudipteryx.jpg", it has been deleted from Commons by [[commons:User:MichaelMaggs|MichaelMaggs]] because: per [[w:commons:Commons:Deletion_requests/Image:Caudipteryx.jpg]]. {{Taxobox | name = ''Caudipteryx'' | fossil_range = [[Early Cretaceous]] | image = Caudipteryx zoui 2.JPG | image_width = 250px | image_caption = ''Caudipteryx zoui'' fossil replica displayed in the [[Hong Kong Science Museum]]. | regnum = [[Animal]]ia | phylum = [[Chordate|Chordata]] | classis = [[Reptile|Sauropsida]] | superordo = [[Dinosaur]]ia | ordo = [[Saurischia]] | subordo = [[Theropoda]] | infraordo = [[Oviraptorosauria]] | familia = '''Caudipteridae''' | familia_authority = [[Zhonghe Zhou|Zhou]] & [[Xiaolin Wang|Wang]], 2000 | genus = '''''Caudipteryx''''' | genus_authority = [[Qiang Ji|Ji]] ''et al.'', 1998 | subdivision_ranks = [[Species]] | subdivision = ''C. zoui'' <small>Ji ''et al.'', 1998 ([[Type species|type]])</small><br /> ''C. dongi'' <small>Zhou & Wang, 2000</small><br /> }} '''''Caudipteryx''''' (which means "tail feather") is a [[genus]] of [[peacock]]-sized [[theropod]] [[dinosaur]]s that lived in the [[Barremian]] age of the early [[Cretaceous]] Period (about 127 [[million years ago]]). They were [[feather]]ed and remarkably [[bird]]like in their overall appearance.<ref name = "jietal1998">Ji, Q., Currie, P.J., Norell, M.A., and Ji, S. (1998). "Two feathered dinosaurs from northeastern China." ''Nature'', '''393'''(6687): 753–761. <small>{{DOI|10.1038/31635}}</small>[http://www.biology.ualberta.ca/faculty/philip_currie/uploads/pdfs/1998/1998Caudipteryx.pdf PDF fulltext]</ref> Two [[species]] have been described; ''C. zoui'' (the [[Type (zoology)|type species]]), in 1998,<ref name = "jietal1998"/> and ''C. dongi'', in 2000.<ref name="zhou&wang2000"/> ''Caudipteryx'' [[fossil]]s were first discovered in the [[Yixian Formation]] of the Sihetun area of [[Liaoning]] Province, northeastern [[China]] in 1997. ==Anatomy== [[Image:Caudipteryx-scale.png|thumb|left|Size comparison of ''Caudipteryx'' to a human.]] ''Caudipteryx'', like many other [[maniraptora]]ns, has an interesting mix of reptile- and bird-like anatomical features.<ref name="Witmer02">Witmer, L.M. (2005). “The Debate on Avian Ancestry; Phylogeny, Function and Fossils”, ''Mesozoic Birds: Above the Heads of Dinosaurs'' : 3–30. ISBN 0-520-20094-2</ref> ''Caudipteryx'' had a short, boxy [[skull]] with a beak-like snout that retained only a few tapered teeth in the front of the upper jaw. It had a stout trunk, long legs and was probably a swift runner. On the hands it had symmetrical, pennaceous, feathers that had vanes and barbs, and that measured between 15–20&nbsp;centimeters (6–8&nbsp;inches). These primary feathers were arranged in a wing-like fan along the second finger, just like primary feathers of birds and other [[maniraptora]]ns. No fossil of ''Caudipteryx'' preserves any secondary feathers attached to the forearms, as found in [[dromaeosaurid]]s, ''[[Archaeopteryx]]'' and modern birds.<ref name="Witmer02"/> Either these arm feathers are not preserved, or they were not present on ''Caudipteryx'' in life. An additional fan of feathers existed on its short tail. The shortness and symmetry of the feathers, and the shortness of the arms relative to the body size, indicate that ''Caudipteryx'' could not fly. ''Caudipteryx'' is thought to have been an [[omnivore]]. In at least two specimens of ''Caudipteryx'' (NGMC 97 4 A and NGMC 97 9 A), [[gastrolith]]s are preserved. As in some herbivorous dinosaurs, the [[Avialae|avialan]] ''[[Sapeornis]]'', and modern birds, these gastroliths remain in the position where the animals’ [[gizzard]]s would have been.<ref name="jietal1998"/> ''Caudipteryx'' has a short, distally stiffened, tail with few vertebrae, like in birds and other [[oviraptorosaur]]s. It has a primitive pelvis and shoulder, and primitive skull details in the quadratojugal, squamosal, quadrate, jugal, and mandibular fenestra (in the cheek, jaw, and jaw joint). It has a hand skeleton with a reduced third finger, like that of primitive birds and the oviraptorid ''[[Ingenia]]''.<ref name="Osmolskaetal.04">Osmolska, H., Currie, P.J., and Barsbold, R. (2004). "Oviraptorosauria." In Weishampel, Dodson, Osmolska (eds.) ''The Dinosauria'', second edition. University of California Press, 2004.</ref> ''Caudipteryx'' had uncinate processes on the ribs, birdlike teeth, a first toe which may or may not be partially reversed and overall body proportions that are comparable to those of modern flightless birds.<ref name="jietal1998"/><ref name="zhouetal2000">Zhou, Z., Wang, X., Zhang, F., and Xu, X. (2000). "Important features of ''Caudipteryx'' - Evidence from two nearly complete new specimens." ''Vertebrata Palasiatica'', '''38'''(4): 241–254. [http://www.ivpp.ac.cn/pdf/magazine232.pdf PDF fulltext]</ref><ref name="zhou&wang2000">Zhou, Z., and Wang, X. (2000). "A new species of ''Caudipteryx'' from the Yixian Formation of Liaoning, northeast China." ''Vertebrata Palasiatica'', '''38'''(2): 113–130. [http://www.ivpp.ac.cn/pdf/magazine213.pdf PDF fulltext]</ref><ref name="jonesetal2000">Jones, T.D., Farlow, J.O., Ruben, J.A., Henderson, D.M., and Hillenius, W.J. (2000). "Cursoriality in bipedal archosaurs." ''Nature'', '''406'''(6797): 716–718. <small>{{DOI|10.1038/35021041}}</small> [http://arnica.csustan.edu/jones/Publications/pdf/Cursoriality.pdf PDF fulltext] [http://www.nature.com/nature/journal/v406/n6797/suppinfo/406716a0.html Supplementary information]</ref><ref name="Witmer02"/> ==Implications== [[Image:Caudipteryx zoui.JPG|thumb|left|''Caudipteryx zoui'' fossil displayed in Hong Kong Science Museum.]] The discovery of ''Caudipteryx'' led to many intensive studies on and debate over the relationship of birds and dinosaurs. The possible positions in the debate can be summarized as follows: ''Caudipteryx'' is either a member of the [[Oviraptorosauria]], or a bird, or both, and birds are either dinosaurs or they are not. (See the rest of this section and Phylogeny, below). Because ''Caudipteryx'' has clear and unambiguously pennaceous feathers, like modern birds, and because several cladistic analyses have consistently recovered it as a nonavian, oviraptorid, dinosaur, it provided, at the time of its description, the clearest and most succinct evidence that birds evolved from dinosaurs. [[Lawrence Witmer]] stated: “The presence of unambiguous feathers in an unambiguously nonavian theropod has the rhetorical impact of an atomic bomb, rendering any doubt about the theropod relationships of birds ludicrous.”<ref name="Witmer02"/> However, not all scientists agreed that ''Caudipteryx'' was unambiguously non-avian, and some of them continued to doubt that general consensus.A paleontologist like [[Alan Feduccia]], who opposes the theory that birds are theropods, sees ''Caudipteryx'' as a flightless bird unrelated to dinosaurs.<ref name="Feduccia">Feduccia, A. (1999). ''The Origin and Evolution of Birds''. 420 pp. Yale University Press, New Haven. ISBN 0300078617.</ref> Jones ''et al.'' (2000) found that ''Caudipteryx'' was a bird based on a mathematical comparison of the body proportions of flightless birds and non-avian theropods. Dyke and Norell (2005) criticized this result for flaws in their mathematical methods, and produced results of their own which supported the opposite conclusion.<ref name="jonesetal2000">Jones, T.D., Farlow, J.O., Ruben, J.A., Henderson, D.M., and Hillenius, W.J. (2000). "Cursoriality in bipedal archosaurs." ''Nature'', '''406'''(6797): 716–718. <small>{{DOI|10.1038/35021041}}</small> [http://arnica.csustan.edu/jones/Publications/pdf/Cursoriality.pdf PDF fulltext] [http://www.nature.com/nature/journal/v406/n6797/suppinfo/406716a0.html Supplementary information]</ref><ref name="dyke&norell2005">Dyke, G.J., and Norell, M.A. (2005). "''Caudipteryx'' as a non-avialan theropod rather than a flightless bird." ''Acta Palaeontologica Polonica'', '''50'''(1): 101–116. [http://www.app.pan.pl/acta50/app50-101.pdf PDF fulltext]</ref> Other researchers not normally involved in the debate over bird origins, such as Zhou, acknowledged that the true affinities of ''Caudipteryx'' were debatable.<ref name="zhouetal2000">Zhou, Z., Wang, X., Zhang, F., and Xu, X. (2000). "Important features of ''Caudipteryx'' - Evidence from two nearly complete new specimens." ''Vertebrata Palasiatica'', '''38'''(4): 241–254. [http://www.ivpp.ac.cn/pdf/magazine232.pdf PDF fulltext]</ref> ==Phylogenetic position== The consensus view, based on several [[cladistic]] analyses, is that ''Caudipteryx'' is a basal (primitive) member of the [[Oviraptoridae]], and the oviraptorids are nonavian theropod dinosaurs.<ref name="Dyke05">Dyke, Gareth J., Norell, Mark A. (2005). "''Caudipteryx'' as a non-avialan theropod rather than a flightless bird". ''Acta Palaeontologica Polonica'', 50(1):101–116.</ref> ''Incisivosaurus'' is the only oviraptorid that is more primitive.<ref name=turneretal2007a>{{cite journal |last=Turner |first=Alan H. |coauthors= Pol, Diego; Clarke, Julia A.; Erickson, Gregory M.; and Norell, Mark |year=2007 |title=A basal dromaeosaurid and size evolution preceding avian flight |url=http://www.sciencemag.org/cgi/reprint/317/5843/1378.pdf |format=pdf |journal=Science |volume=317 |pages=1378–1381 |doi=10.1126/science.1144066 |pmid=17823350 }}</ref> Halszka Osmolska ''et al.'' (2004) ran a cladistic analysis that came to a different conclusion. They found that the most birdlike features of oviraptorids actually place the whole clade within Aves itself, meaning that ''Caudipteryx'' is both an oviraptorid and a bird. In their analysis, birds evolved from more primitive theropods, and one lineage of birds became flightless, re-evolved some primitive features, and gave rise to the oviraptorids. This analyis was persuasive enough to be included in paleontological textbooks like Benton's ''Vertebrate Paleontology'' (2005).<ref name="Osmolskaetal04">Osmolska, Halszka, Currie, Philip J., Barsbold, Rinchen (2004) ''The Dinosauria'' Weishampel, Dodson, Osmolska. "Chapter 8 Oviraptorosauria" University of California Press.</ref> The view that ''Caudipteryx'' was secondarily flightless is also preferred by [[Gregory S. Paul]],<ref name="paul2002">Paul, G.S. (2002). ''Dinosaurs of the Air: The Evolution and Loss of Flight in Dinosaurs and Birds.'' Johns Hopkins University Press, Baltimore. <small>ISBN 0801867630</small></ref> [[Junchang Lü|Lü]] ''et al'',<ref name="luetal2002">Lü, J., Dong, Z., Azuma, Y., Barsbold, R., and Tomida, Y. (2002). "Oviraptorosaurs compared to birds." In Zhou, Z., and Zhang, F. (eds.), ''Proceedings of the 5th Symposium of the Society of Avian Paleontology and Evolution'', 175–189. Beijing Science Press.</ref> and Maryanska ''et al''.<ref name="maryanskaetal2002">Maryanska, T., Osmólska, H., and Wolsam, M. (2002). "Avialian status for Oviraptorosauria." ''Acta Palaeontologica Polonica'', '''47'''(1): 97–116. [http://app.pan.pl/acta47/app47-097.pdf PDF fulltext]</ref> Others, such as Stephen Czerkas and [[Larry Martin]] have concluded that ''Caudipteryx'' is not a [[theropod]] dinosaur at all.<ref name=”Martin04”>Martin, Larry D.,(2004) “A basal archosaurian origin for birds”, ''Acta Zoologica Sinica'' 50(6):978–990</ref> They believe that ''Caudipteryx'', like all [[maniraptora]]ns, is a flightless bird, and that birds evolved from non-dinosaurian archosaurs.<ref name="martin&czerkas2000">Martin, L.D., and Czerkas, S.A. (2000). "The Fossil Record of Feather Evolution in the Mesozoic." ''American Zoologist'', '''40'''(4): 687–694. [http://icb.oxfordjournals.org/cgi/reprint/40/4/687.pdf PDF fulltext]</ref> ==References==<!-- Zool.J.Linn.Soc.131:123;131:169 --> {{reflist}} ==External links== * Australian Museum: [http://www.amonline.net.au/chinese_dinosaurs/factsheets/13.htm Chinese Dinosaurs: ''Caudipteryx zoui'']. Retrieved 2007-FEB-19. * Dino Russ's Lair: [http://www.dinoruss.com/jim-robins-art/Caudipteryx.gif ''Caudipteryx'' reconstruction] by paleoartist Jim Robins. Retrieved 2007-FEB-19. * Natural History Museum of Los Angeles County: [http://www.nhm.org/journey/prehist/birds/caudipteryx.html From Dinosaurs to Birds: ''Caudipteryx'']. Retrieved 2007-FEB-19. * Research Casting International: [http://www.rescast.com/specimens/show_specimen.php?SpecimenID=163 Life-size model of ''Caudipteryx zoui'']. Retrieved 2007-FEB-19. * CNN: [http://www.cnn.com/TECH/science/9806/23/feathered.dinosaur/ Scientists: Fossils prove that birds evolved from dinosaurs]. Retrieved 2007-AUG-10 {{portalpar|Dinosaurs}} [[Category:Cretaceous dinosaurs]] [[Category:Dinosaurs of Asia]] [[Category:Feathered dinosaurs]] [[Category:Oviraptorosaurs]] [[cs:Caudipteryx]] [[de:Caudipteryx]] [[es:Caudipteryx]] [[id:Caudipteryx]] [[it:Caudipteryx]] [[ja:カウディプテリクス]] [[pl:Kaudipteryks]] [[simple:Caudipteryx]] [[sk:Caudipteryx]] [[fi:Caudipteryx]] [[zh:尾羽龙]]