Editing Caudipteryx

{{Short description|Genus of oviraptorosaur dinosaurs}}
{{Use dmy dates|date=January 2024}}
{{Automatic taxobox
| fossil_range = [[Early Cretaceous]], ([[Aptian]]) ~{{fossil range|124.6}}
| image = Caudipteryx zoui - Untere Kreide - Liaoning-China.jpg
| image_caption = Mounted ''Caudipteryx zoui'' skeleton at [[Löwentor Museum]]
| display_parents = 2
| taxon = Caudipteryx
| authority = Ji ''et al.'' 1998
| type_species = {{extinct}}'''''Caudipteryx zoui'''''
| type_species_authority = Ji ''et al.'', 1998 
| subdivision_ranks = Other species
| subdivision =
* {{extinct}}'''''C. dongi?'''''{{Citation needed|reason=No source for why this species is considered questionable|date=March 2025}} <br/><small>Zhou & Wang, 2000</small>
}}

'''''Caudipteryx''''' (meaning "tail feather") is a [[genus]] of small [[oviraptorosaur]] [[dinosaur]]s that lived in [[Asia]] during the [[Early Cretaceous]], around 124.6 million years ago. They were [[feather]]ed and extremely [[bird]]like in their overall appearance, to the point that some [[paleontologists]] suggested it was a [[bird]]. Two [[species]] have been described: ''C. zoui'' (the [[Type (zoology)|type species]]), in 1998, and ''C. dongi'', in 2000.

It had a stout trunk, long legs and was probably a swift runner. The discovery of ''Caudipteryx'' has led to many intensive studies and debate over the relationship of birds and dinosaurs.

==History==
{{multiple image
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|image2=Caudipteryx-Geological Museum of China.jpg
|caption2=Holotype of ''C. zoui'', at the [[Geological Museum of China]]
|image1=Caudipteryx zoui.JPG
|caption1=Paratype of ''C. zoui'', at the [[Hong Kong Science Museum]]
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In 1997, several well-preserved [[dinosaur]] skeletons were recovered from the Jiulongsong Member of the [[Chaomidianzi Formation]] (now Jianshangou Bed of the [[Yixian Formation]]), at the Sihetun locality of [[Liaoning province]], [[China]]. The [[fossil]]s were later described in 1998 and used as the type specimens for the new dinosaur taxa ''Caudipteryx'' and ''[[Protarchaeopteryx]]''. ''Caudipteryx'' was erected with the type species ''C. zoui'' and the [[holotype]] is NGMC 97-4-A, a nearly complete individual preserving conspicuous feather impressions and [[gastroliths]]. The [[paratype]] is NGMC 97-9-A, another relatively complete individual with feather impressions. The [[Genus#Use|generic name]], ''Caudipteryx'', means "tail feather", and the [[Specific name (zoology)|specific name]], ''zoui'', is in honor of [[Zou Jiahua]] for his prominent support to the scientific community as the [[vice premier]] of China.<ref name="jietal1998">{{cite journal |last1=Ji |first1=Q. |last2=Currie |first2=P.J. |last3=Norell |first3=M.A. |last4=Ji |first4=S. |year=1998 |title=Two feathered dinosaurs from northeastern China |url=http://www.biology.ualberta.ca/faculty/philip_currie/uploads/pdfs/1998/1998Caudipteryx.pdf |url-status=dead |journal=Nature |volume=393 |issue=6687 |pages=753–761 |bibcode=1998Natur.393..753Q |doi=10.1038/31635 |archive-url=https://web.archive.org/web/20081217154732/http://www.biology.ualberta.ca/faculty/philip_currie/uploads/pdfs/1998/1998Caudipteryx.pdf |archive-date=17 December 2008 |s2cid=205001388}}</ref>

Around the summer of 1988, a partially complete skeleton of ''Caudipteryx'' lacking the skull was found in sediments of the "Layer 6" of the Yixian Formation, at the Zhangjiagou locality, which is set apart {{convert|3|km|mi|abbr=on}} from Sihetun. This specimen, IVPP V 12344, was in 2000 described and designed as the holotype for new species ''Caudipteryx dongi'', and in a similar fashion to previous specimens of the genus, it preserves exquisite traces of feather integument. The specific name ''dongi'' honors [[Zhiming Dong]], a Chinese [[paleontologist]].<ref name="zhou&wang2000">{{cite journal | last1 = Zhou | first1 = Z. | last2 = Wang | first2 = X. | year = 2000 | title = A new species of ''Caudipteryx'' from the Yixian Formation of Liaoning, northeast China | url = http://www.ivpp.ac.cn/pdf/magazine213.pdf | journal = Vertebrata PalAsiatica | volume = 38 | issue = 2 | pages = 113–130 | url-status = dead | archive-url = https://web.archive.org/web/20071007140842/http://www.ivpp.ac.cn/pdf/magazine213.pdf | archive-date = 7 October 2007 }}</ref>

===Additional specimens===
[[File:Caudipteryx STM4-3.png|thumb|Specimen STM4-3 and line diagram]]
During 2000, Zhong-He Zhou and colleagues described two additional specimens of ''Caudipteryx'', BPM 0001 and IVPP V 12430, referred to ''C. zoui'' and ''C.'' sp. respectively. Both individuals preserve nearly complete skulls and have feather impressions.<ref name="zhouetal2000">{{cite journal | last1 = Zhou | first1 = Z. | last2 = Wang | first2 = X. | last3 = Zhang | first3 = F. | last4 = Xu | first4 = X. | year = 2000 | title = Important features of ''Caudipteryx'' - Evidence from two nearly complete new specimens | url = https://www.researchgate.net/publication/260714709 | journal = Vertebrata PalAsiatica | volume = 38 | issue = 4 | pages = 241–254 }}</ref> Further analyses to IVPP V 12430 have revealed the preservation of propatagium on its left arm.<ref>{{cite journal|last1=Uno|first1=Y.|last2=Hirasawa|first2=T.|date=2023|title=Origin of the propatagium in non-avian dinosaurs|journal=Zoological Letters|volume=9|number=4|page=4 |doi=10.1186/s40851-023-00204-x|doi-access=free|pmid=36823531 |pmc=9951497}}</ref>

In 2021 Xiaoting Zheng and team described STM4-3 representing an articulated individual lacking the skull and tail tip, including abundant integument, gastroliths, but also a cartilage fragment that was reported to preserve [[chondrocyte]]s. The specimen was collected from outcrops of the Yixian Formation at Dapingfang Town near [[Chaoyang, Liaoning|Chaoyang]] city, west [[Liaoning]].<ref>{{cite journal|last1=Zheng|first1=X.|last2=Bailleul|first2=A. M.|last3=Li|first3=Z.|last4=Zhou|first4=Z.|date=2021|title=Nuclear preservation in the cartilage of the Jehol dinosaur Caudipteryx|journal=Communications Biology|volume=4|number=1125|page=1125 |doi=10.1038/s42003-021-02627-8|doi-access=free|pmc=8463611|pmid=34561538}}</ref>

==Description==
===Size===
[[File:Caudipteryx Scale.svg|thumb|Size comparison of ''Caudipteryx'' species to a human]] 
''Caudipteryx'' was a small theropod, measuring {{cvt|72.5|-|89|cm|ftin}} long and weighing about {{cvt|5|kg|lb}} based on femur length.<ref name="jietal1998"/><ref name="zhou&wang2000"/><ref>{{cite journal|author1=Talori, Y.S.|author2=Zhao, J.-S.|author3=Liu, Y.-F.|author4=Lu, W.-X.|author5=Li, Z.-H.|author6=O'Connor, J.K.|year=2019|title=Identification of avian flapping motion from non-volant winged dinosaurs based on modal effective mass analysis|journal=PLOS Computational Biology|volume=15|issue=5|at=e1006846|doi=10.1371/journal.pcbi.1006846|pmid=31048911 |pmc=6497222 |bibcode=2019PLSCB..15E6846T |doi-access=free }}</ref> Like many other [[maniraptora]]ns, has a 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>

===Skull===
It had a short, boxy [[skull]] with a beak-like snout that retained only a few tapered teeth in the front of the upper jaw.<ref name="zhou&wang2000"/>

===Postcranial skeleton===
Its short tail was stiffened toward the tip, 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 early birds and the oviraptorid ''[[Heyuannia]]''.<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="zhou&wang2000"/><ref name="Witmer02"/><ref name="zhouetal2000"/><ref name="jonesetal2000">{{cite journal | last1 = Jones | first1 = T.D. | last2 = Farlow | first2 = J.O. | last3 = Ruben | first3 = J.A. | last4 = Henderson | first4 = D.M. | last5 = Hillenius | first5 = W.J. | year = 2000 | title = Cursoriality in bipedal archosaurs | journal = Nature | pmid = 10963594 | volume = 406 | issue = 6797| pages = 716–718 | doi = 10.1038/35021041 | bibcode = 2000Natur.406..716J | s2cid = 4395244 | url = http://doc.rero.ch/record/13870/files/PAL_E797.pdf }} [https://web.archive.org/web/20060908145836/http://arnica.csustan.edu/jones/Publications/pdf/Cursoriality.pdf PDF] [http://www.nature.com/nature/journal/v406/n6797/suppinfo/406716a0.html Supplementary information]</ref>

===Feathers===
[[File:Caudipteryx wing feathers.png|thumb|Wing reconstruction and feather impressions of ''Caudipteryx'' sp. (a) and ''C. dongi'' (b)]]
The hands of ''Caudipteryx'' supported symmetrical, pennaceous feathers that had vanes and barbs, measuring between {{convert|15|and|20|cm|abbr=off|sp=}} long. The primary feathers were arranged in a wing-like fan along the second finger, just like primary feathers of birds and other [[maniraptora]]ns. An additional fan of feathers existed on its tail. The body of ''C. zoui'' was covered in black feathers, with a visible banding pattern preserved on tail feathers.<ref>{{cite journal|first1=Arindam |last1=Roy|first2=Michael|last2=Pittman|first3=Evan T.|last3=Saitta|first4=Thomas G.|last4=Kaye|first5=Xing|last5=Xu|year=2020|title=Recent advances in amniote palaeocolour reconstruction and a framework for future research|journal=Biological Reviews|volume=95|issue=1 |pages=22–50|doi=10.1111/brv.12552|pmid=31538399 |pmc=7004074 }}</ref>

A study on the number of flight feathers has concluded that ''Caudipteryx'' was secondarily flightless.<ref>{{cite journal |last1=Kiat |first1=Yosef |last2=O’Connor |first2=Jingmai K. |title=Functional constraints on the number and shape of flight feathers |journal=Proceedings of the National Academy of Sciences |date=20 February 2024 |volume=121 |issue=8 |pages=e2306639121 |doi=10.1073/pnas.2306639121 |pmid=38346196 |issn=0027-8424|pmc=10895369 |bibcode=2024PNAS..12106639K }}</ref>

==Classification==
[[File:Caudipteryx UDL.png|thumb|right|[[Life restoration]]]] 
The consensus view, based on several [[Cladistics|cladistic]] analyses, is that ''Caudipteryx'' is a basal (primitive) member of the [[Oviraptorosauria]], and the oviraptorosaurians are non-avian theropod dinosaurs.<ref name="Dyke05" /> ''[[Incisivosaurus]]'' is the only oviraptorosaur that is more primitive.<ref name=turneretal2007a>{{cite journal |last=Turner |first=Alan H. |author2=Pol, Diego |author3=Clarke, Julia A. |author4=Erickson, Gregory M. |author5=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 |journal=Science |volume=317 |pages=1378–1381 |doi=10.1126/science.1144066 |pmid=17823350 |issue=5843 |bibcode=2007Sci...317.1378T |doi-access=free }}</ref>

Halszka Osmólska ''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 analysis was persuasive enough to be included in paleontological textbooks like Benton's ''Vertebrate Paleontology'' (2005).<ref name="Osmolskaetal04">Osmólska, 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. {{ISBN|0-8018-6763-0}}</ref> [[Lü Junchang|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 [[Teresa Maryańska|Maryańska]] ''et al.''<ref name="maryanskaetal2002">{{cite journal | last1 = Maryańska | first1 = T. | last2 = Osmólska | first2 = H. | last3 = Wolsan | first3 = M. | year = 2002 | title = Avialan status for Oviraptorosauria | url = http://www.app.pan.pl/archive/published/app47/app47-097.pdf | journal = Acta Palaeontologica Polonica | volume = 47 | issue = 1| pages = 97–116 }}</ref>

Others, such as Stephen Czerkas and [[Larry Martin]] have concluded that ''Caudipteryx'' is not a [[Theropoda|theropod]] dinosaur at all.<ref name="Martin04">{{cite journal | last1 = Martin | first1 = Larry D. | year = 2004 | title = A basal archosaurian origin for birds | journal = Acta Zoologica Sinica | volume = 50 | issue = 6| pages = 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">{{cite journal | doi = 10.1668/0003-1569(2000)040[0687:TFROFE]2.0.CO;2 | citeseerx = 10.1.1.505.6483 | last1 = Martin | first1 = L.D. | last2 = Czerkas | first2 = S.A. | year = 2000 | title = The Fossil Record of Feather Evolution in the Mesozoic | journal = American Zoologist | volume = 40 | issue = 4| pages = 687–694 | s2cid = 85701665 }}</ref>

A weighted cladogram from 2014, using TNT, is shown below.<ref name="godefroitetal2014">{{Cite journal | last1 = Godefroit | first1 = Pascal | last2 = Cau| first2 = Andrea | last3 = Hu | first3 = Dong-Yu| last4 = Escuillié | first4 = François| last5 = Wu | first5 = Wenhao| last6 = Dyke | first6 = Gareth| doi = 10.1038/nature12168 | title = A Jurassic avialan dinosaur from China resolves the early phylogenetic history of birds | journal = Nature | volume = 498| issue = 7454| pages =359–362| year = 2013 | pmid =  23719374| bibcode = 2013Natur.498..359G | s2cid = 4364892 }}</ref>

{{clade| style=font-size:85%; line-height:85%
|label1=[[Oviraptorosauria]]
|1={{clade
 |1=''[[Protarchaeopteryx]]''
 |2={{clade
  |1=''[[Incisivosaurus]]''
  |2={{clade
   |1=''[[Similicaudipteryx]]''
   |2={{clade
    |1={{clade
     |1=''[[Avimimus]]''
     |2=''[[Microvenator]]'' }}
    |2={{clade
     |1='''''Caudipteryx'''''
     |label2=[[Caenagnathoidea]]
     |2={{clade
      |label1=[[Caenagnathidae]]
      |1={{clade
       |1=''[[Chirostenotes]]''
       |2=''[[Gigantoraptor]]'' }}
      |label2=[[Oviraptoridae]]
      |2={{clade
       |1=''[[Oviraptor]]''
       |2={{clade
        |1=''[[Citipati (dinosaur)|Citipati]]''
        |2=''[[Khaan]]'' }} }} }} }} }} }} }} }} }}

===Relationship with birds===
[[File:Caudipteryx.gif|thumb|right|Skeletal restorations of three specimens]] 
Because ''Caudipteryx'' has clear and unambiguously pennaceous feathers, like modern birds, and because several cladistic analyses have consistently recovered it as a non-avian 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 non-avian 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. Paleornithologist [[Alan Feduccia]] sees ''Caudipteryx'' as a flightless bird evolving from earlier [[archosaur]]ian dinosaurs rather than from late theropods.<ref name="Feduccia">Feduccia, A. (1999). ''The Origin and Evolution of Birds''. 420 pp. Yale University Press, New Haven. {{ISBN|0-300-07861-7}}.</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"/><ref name="Dyke05">{{cite journal | last1 = Dyke | first1 = Gareth J. | last2 = Norell | first2 = Mark A. | year = 2005 | title = ''Caudipteryx'' as a non-avialan theropod rather than a flightless bird | url = http://www.app.pan.pl/archive/published/app50/app50-101.pdf | journal = Acta Palaeontologica Polonica | volume = 50 | issue = 1| pages = 101–116 }}</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"/>

==Paleobiology==
===Diet===
[[File:Caudipteryx zoui (BPV 085) gastroliths.jpg|thumb|Gastroliths in stomach region of ''C. zoui'' specimen BPV 085, [[National Museum of Natural Science]]]] 
''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"/>

==Paleoenvironment==
All ''Caudipteryx'' [[fossil]]s were recovered from the [[Yixian Formation]] in [[Liaoning]], [[China]]. Specifically, they come from a small area of the Jianshangou bed, near the town of [[Zhangjiakou]]. They appear to have been fairly common, though isolated to this small region. The specific region in which ''Caudipteryx'' lived was home to the other feathered dinosaurs ''[[Dilong (dinosaur)|Dilong]]'' and ''[[Sinornithosaurus]]''.<ref name="xu&norell2006">{{cite journal | doi = 10.1002/gj.1044 | last1 = Xu | first1 = X. | last2 = Norell | first2 = M.A. | year = 2006 | title = Non-Avian dinosaur fossils from the Lower Cretaceous Jehol Group of western Liaoning, China | journal = Geological Journal | volume = 41 | issue = 3–4| pages = 419–437 | bibcode = 2006GeolJ..41..419X | s2cid = 32369205 }}</ref>

==See also==
{{Portal|Dinosaurs}}
* [[Dinosaur coloration]]
* [[Timeline of oviraptorosaur research]]

==References==
{{Reflist}}

==External links==
* {{Commons category-inline|Caudipteryx|''Caudipteryx''}}
* {{Wikispecies-inline|Caudipteryx|''Caudipteryx''}}
* Australian Museum: [https://web.archive.org/web/20040604143708/http://www.amonline.net.au/chinese_dinosaurs/factsheets/13.htm Chinese Dinosaurs: ''Caudipteryx zoui'']. Retrieved 2007-FEB-19.
* Natural History Museum of Los Angeles County: [https://web.archive.org/web/20040517083041/http://www.nhm.org/journey/prehist/birds/caudipteryx.html From Dinosaurs to Birds: ''Caudipteryx'']. Retrieved 2007-FEB-19.
* Research Casting International: [https://web.archive.org/web/20080319035031/http://www.rescast.com/specimens/show_specimen.php?SpecimenID=163 Life-size model of ''Caudipteryx zoui'']. Retrieved 2007-FEB-19.
* CNN: [https://web.archive.org/web/20071117091248/http://www.cnn.com/TECH/science/9806/23/feathered.dinosaur/ Scientists: Fossils prove that birds evolved from dinosaurs]. Retrieved 2007-AUG-10

{{Oviraptorosauria}}
{{Taxonbar|from=Q131069}}

[[Category:Oviraptorosauria]]
[[Category:Dinosaur genera]]
[[Category:Barremian dinosaurs]]
[[Category:Yixian Formation]]
[[Category:Fossil taxa described in 1998]]
[[Category:Taxa named by Philip J. Currie]]
[[Category:Taxa named by Mark Norell]]
[[Category:Dinosaurs of China]]
[[Category:Feathered dinosaurs]]