Editing Microraptor (section)

==History==
===Naming controversy===
{{Main|Archaeoraptor}}
[[File:Archaeoraptor-Paleozoological Museum of China.jpg|alt=|thumb|The "[[Archaeoraptor]]" fossil; the tail belongs to ''Microraptor'']]
The initial naming of ''Microraptor'' was controversial, because of the unusual circumstances of its first description. The first specimen to be described was part of a chimeric specimen—a patchwork of different feathered dinosaur species (''Microraptor'' itself, ''[[Yanornis]]'' and an as-of-yet undescribed third species) assembled from multiple specimens in China and smuggled to the USA for [[Fossil collecting|sale]]. After the forgery was revealed by [[Xu Xing (paleontologist)|Xu Xing]] of [[Beijing]]'s [[Institute of Vertebrate Paleontology and Paleoanthropology]], [[Storrs L. Olson]], curator of birds in the [[National Museum of Natural History]] of the [[Smithsonian Institution]], published a description of the Microraptor's tail in an obscure journal, giving it the name ''Archaeoraptor liaoningensis'' in an attempt to remove the name from the paleornithological record by assigning it to the part least likely to be a bird.<ref name="olson2000">Olson, S.L. (2000). "Countdown to Piltdown at ''National Geographic'': the rise and fall of ''Archaeoraptor''." ''Backbone'', '''13'''(2) (April): 1–3.</ref> However, Xu had discovered the remains of the specimen from which the tail had been taken and published a description of it later that year, giving it the name ''Microraptor zhaoianus''.<ref name="Xu2000">Xu, X., Zhou, Z., and Wang, X. (2000). "The smallest known non-avian theropod dinosaur." ''Nature'', '''408''' (December): 705-708.{{cite web |url=http://research.amnh.org/%7Esunny/microraptor.pdf |title=Archived copy |access-date=2008-12-17 |url-status=dead |archive-url=https://web.archive.org/web/20081217154907/http://research.amnh.org/%7Esunny/microraptor.pdf |archive-date=2008-12-17 }}</ref>

Since the two names designate the same individual as the [[Type (biology)|type]] specimen, ''Microraptor zhaoianus'' would have been a [[junior objective synonym]] of ''Archaeoraptor liaoningensis'' and the latter, if valid, would have had priority under the [[International Code of Zoological Nomenclature]]. However, there is some doubt whether Olson in fact succeeded in meeting all the formal requirements for establishing a new taxon. Namely, Olson designated the specimen as a [[lectotype]], before an actual type species was formally erected.<ref name=dmlarchaeoraptor>Creisler, B. (2002). "[http://dml.cmnh.org/2001Jan/msg00092.html Archaeoraptor still a nomen nudum] {{Webarchive|url=https://web.archive.org/web/20080725160846/http://dml.cmnh.org/2001Jan/msg00092.html |date=2008-07-25 }}." Message to the Dinosaur Mailing List, 4 Jan 2001. accessed 23 Sep 2009.</ref> A similar situation arose with ''[[Tyrannosaurus rex]]'' and ''Manospondylus gigas'', in which the former became a ''nomen protectum'' and the latter a ''nomen oblitum'' due to revisions in the ICZN rules that took place on December 31, 1999.<ref name="sowhyhasn">{{Cite web|title=So why hasn't Tyrannosaurus been renamed Manospondylus?|url=http://www.miketaylor.org.uk/dino/faq/s-class/priority/|access-date=2023-02-07|website=The Dinosaur FAQ |last=Taylor |first=M. |author-link=Michael P. Taylor |date=2002-08-27}}</ref> In addition, Xu's name for the type specimen (''Microraptor'') was subsequently used more frequently than the original name; as such, this and the chimeric nature of the specimen would render the name "Archaeoraptor" a ''nomen vanum'' (as it was improperly described) and the junior synonym ''Microraptor'' a ''nomen protectum'' (as it's been used in more published works than "Archaeoraptor" and was properly described).<ref name=dmlarchaeoraptorvmicroraptor>Williams, T. (2002). "[http://dml.cmnh.org/2001Jan/msg00020.html Archaeoraptor v Microraptor] {{Webarchive|url=https://web.archive.org/web/20160303215023/http://dml.cmnh.org/2001Jan/msg00020.html |date=2016-03-03 }}." Message to the Dinosaur Mailing List, 1 Jan 2001. accessed 30 Sept 2014.</ref>

===Additional specimens===
[[File:Microraptor Skeletons by Qilong.jpg|thumb|Skeletal restorations of various specimens]]
The first specimen referred to ''Microraptor'' represented a small individual and included faint feather remnants, but was otherwise not well preserved and lacked a skull.
In 2002 [[Mark Norell]] et al. described another specimen, BPM 1 3-13, which they did not name or refer to an existing species.<ref name="norelletal02">Norell, Mark, Ji, Qiang, Gao, Keqin, Yuan, Chongxi, Zhao, Yibin, Wang, Lixia. (2002). "'Modern' feathers on a non-avian dinosaur". ''Nature'', 416: pp. 36. 7 March 2002.></ref> Later that year [[Stephen A. Czerkas|Stephen Czerkas]] et al. named the specimen ''Cryptovolans pauli'', and referred two additional specimens (the first to show well-preserved feathers) to this species. The generic name was derived from Greek ''kryptos'', "hidden", and [[Latin]] ''volans'', "flying". The [[specific name (zoology)|specific name]], ''pauli'', honors [[Paleontology|paleontologist]] [[Gregory S. Paul]], who had long proposed that dromaeosaurids evolved from flying ancestors.<ref name="Czerkas2002"/>

The [[type specimen]]s of ''C. pauli'' were collected from the [[Jiufotang Formation]], dating from the early [[Albian]] and now belong to the collection of the Paleontology Museum of Beipiao, in [[Liaoning]], China. They are referred to by the inventory numbers LPM 0200, the [[holotype]]; LPM 0201, its counterslab (slab and counterslab together represent the earlier BPM 1 3-13); and the [[paratype]] LPM 0159, a smaller skeleton. Both individuals are preserved as articulated compression fossils; they are reasonably complete but partially damaged.<ref name="Czerkas2002"/>
[[File:Microraptor-Beijing Museum of Natural History.jpg|alt=|left|thumb|Specimen at the [[Beijing Museum of Natural History]]]]
Czerkas ''et al.'' (2002) diagnosed the genus on the basis of having primary feathers (which in the authors' opinion made it a [[bird]]), a co-ossified sternum, a tail consisting of 28 to 30 vertebrae and a third finger with a short phalanx III-3.<ref name="Czerkas2002"/> Some of the feathers Czerkas described as primary were actually attached to the leg, rather than the arm. This, along with most of the other diagnostic characters, is also present in the genus ''Microraptor'', which was first described earlier than ''Cryptovolans''.<ref name="Xuetal03">{{cite journal | last1 = Xu | first1 = Xing | last2 = Zhou | first2 = Zhinghe | last3 = Wang | first3 = Xiaolin | last4 = KUang | first4 = Xuewen | last5 = Zhang | first5 = Fucheng | last6 = Du | first6 = Xiangke | year = 2003 | title = Four-winged dinosaurs from China | journal = Nature | volume = 421 | issue = 6921| pages = 335–340 | doi=10.1038/nature01342 | pmid=12540892| bibcode = 2003Natur.421..335X | s2cid = 1160118 | url = http://doc.rero.ch/record/15275/files/PAL_E2574.pdf }}</ref> However, BPM 1 3-13 has a longer tail, proportionately, than other ''Microraptor'' specimens that had been described by 2002, which have 24 to 26 tail vertebrae.<ref name="norelletal02"/>

Subsequent studies (and more specimens of ''Microraptor'') have shown that the features used to distinguish ''Cryptovolans'' are not unique, but are present to varying degrees across various specimens. In a review by Phil Senter and colleagues in 2004, the scientists suggested that all these features represented individual variation across various age groups of a single ''Microraptor'' species, making the name ''Cryptovolans pauli'' and ''Microraptor gui'' junior synonyms of ''Microraptor zhaoianus''.<ref name="senteretal2004"/> Many other researchers, including Alan Feduccia and Tom Holtz, have since supported its synonymy.<ref name="Holtz2008">Holtz, Thomas R. Jr. (2011) ''Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages,'' [http://www.geol.umd.edu/~tholtz/dinoappendix/HoltzappendixWinter2010.pdf Winter 2010 Appendix.]</ref><ref name=FLH05>{{cite journal|last1=Feduccia |first1=A. |year=2005 |title=Do feathered dinosaurs exist? Testing the hypothesis on neontological and paleontological evidence |journal=Journal of Morphology |volume=266 |issue=2 |pages=125–166 |pmid=16217748 |doi=10.1002/jmor.10382|last2=Lingham-Soliar|first2=T|last3=Hinchliffe|first3=JR|s2cid=15079072 }}</ref> ''M. gui'' has been accepted as a distinct species with the specimen reported in 2013 being distinguishable from the type specimen of ''M. zhaoianus''.<ref name=Xing13/>

A new specimen of ''Microraptor'', BMNHC PH881, showed several features previously unknown in the animal, including the probably glossy-black iridescent plumage coloration. The new specimen also featured a bifurcated tailfan, similar in shape to previously known ''Microraptor'' tailfans except sporting a pair of long, narrow feathers at the center of the fan. The new specimen also showed no sign of the nuchal crest, indicating that the crest inferred from the holotype specimen may be an artifact of [[taphonomy|taphonomic]] distortion.<ref name="iridescence"/><ref name="iridescence2"/>

Numerous further specimens likely belonging to ''Microraptor'' have been uncovered, all from the Shangheshou Bed of the [[Jiufotang Formation]] in Liaoning, China. In fact, ''Microraptor'' is the most abundant non-avialan dinosaur fossil type found in this formation.<ref name="xu&norell2006">{{cite journal | 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 | doi = 10.1002/gj.1044 | journal = Geological Journal | volume = 41 | issue = 3–4| pages = 419–437 | bibcode = 2006GeolJ..41..419X | s2cid = 32369205 }}</ref> In 2010, it was reported that there were over 300 undescribed specimens attributable to ''Microraptor'' or its close relatives among the collections of several Chinese museums, though many had been altered or composited by private fossil collectors.<ref name=alexanderetal2010/>

===Study and debate===
[[File:Microraptor zhaoianus.jpg|thumb|upright|Fossil specimen]]
Norell ''et al.'' (2002) described BPM 1 3-13 as the first dinosaur known to have flight feathers on its legs as well as on its arms.<ref name="Norelletal02">{{cite journal | last1 = Norell | first1 = Mark | last2 = Ji | first2 = Qiang | last3 = Gao | first3 = Keqin | last4 = Yuan | first4 = Chongxi | last5 = Zhao | first5 = Yibin | last6 = Wang | first6 = Lixia | year = 2002 | title = 'Modern' feathers on a non-avian dinosaur | journal = Nature | volume = 416 | issue = 6876| pages = 36–7 | doi=10.1038/416036a| pmid = 11882883 | bibcode = 2002Natur.416...36N | s2cid = 4410791 }}</ref>

Czerkas (2002) mistakenly described the fossil as having no long feathers on its legs, but only on its hands and arms, as he illustrated on the cover of his book ''Feathered Dinosaurs and the Origin of Flight''.<ref name="Czerkas2002">Czerkas, Sylvia J. ed. (2002) "Feathered Dinosaurs and the Origin of Flight" The Dinosaur Museum Journal Volume 1. Blanding, Utah, USA. The Dinosaur Museum, August 1, 2002</ref> In his discussion of ''Cryptovolans'' in this book, Czerkas strongly denounces Norell's conclusions; "The misinterpretation of the primary wing feathers as being from the hind legs stems directly to [''sic''] seeing what one believes and wants to see".<ref name="Czerkas2002"/> Czerkas also denounced Norell for failing to conclude that [[Dromaeosauridae|dromaeosaurs]] are birds, accusing him of succumbing to "...the blinding influences of preconceived ideas."<ref name="Czerkas2002"/> The [[crown group]] definition of Aves, as a subset of [[Avialae]], the explicit definition of the term "bird" that Norell employs, would definitely exclude BPM 1 3-13. However, he does not consider the specimen to belong to Avialae either.<ref name="Norelletal02"/>

Czerkas's interpretation of the hindleg feathers noted by Norell proved to be incorrect the following year when additional specimens of ''Microraptor'' were published by Xu and colleagues, showing a distinctive "hindwing" completely separate from the forelimb wing. The first of these specimens was discovered in 2001, and between 2001 and 2003 four more specimens were bought from private collectors by Xu's museum, the [[Institute of Vertebrate Paleontology and Paleoanthropology]]. Xu also considered these specimens, most of which had hindwings and proportional differences from the original ''Microraptor'' specimen, to be a new species, which he named ''Microraptor gui''. However, Senter also questioned this classification, noting that as with ''Cryptovolans'', most of the differences appeared to correspond with size, and likely age differences.<ref name=senteretal2004/> Two further specimens, classified as ''M. zhaoianus'' in 2002 (''M. gui'' had not yet been named), have also been described by Hwang and colleagues.<ref name="hwangetal2002"/>

Czerkas also believed that the animal may have been able to fly better than ''[[Archaeopteryx]]'', the animal usually referred to as the earliest known bird. He cited the fused sternum and asymmetrical feathers, and argued that ''Microraptor'' has modern bird features that make it more derived than ''Archaeopteryx''. Czerkas cited the fact that this possibly volant animal is also very clearly a dromaeosaurid to suggest that the [[Dromaeosauridae]] might actually be a basal bird group, and that later, larger, species such as ''[[Deinonychus]]'' were secondarily flightless (Czerkas, 2002). The current consensus is that there is not enough evidence to conclude whether dromaeosaurs descended from an ancestor with some aerodynamic abilities. The work of Xu ''et al.'' (2003) suggested that basal dromaeosaurs were probably small, arboreal, and could glide.<ref name=xuetal2003>{{cite journal | last1 = Xing | first1 = X. | last2 = Zhou | first2 = Z. | last3 = Wang | first3 = X. | last4 = Kuang | first4 = X. | last5 = Zhang | first5 = F. | last6 = Du | first6 = X. | year = 2003 | title = Four-winged dinosaurs from China | journal = Nature | volume = 421 | issue = 6921| pages = 335–340 | bibcode = 2003Natur.421..335X | doi = 10.1038/nature01342 | pmid = 12540892 | s2cid = 1160118 | url = http://doc.rero.ch/record/15275/files/PAL_E2574.pdf }}</ref> The work of Turner ''et al.'' (2007) suggested that the ancestral dromaeosaur could not glide or fly, but that there was good evidence that it was small-bodied (around 65&nbsp;cm long and 600–700&nbsp;g in mass).<ref name="Turneretal07"/>