Microraptor Fossil range: Early Cretaceous
Fossil specimen of Microraptor gui.
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Sauropsida Superorder: Dinosauria Order: Saurischia Suborder: Theropoda Family: Dromaeosauridae Genus: Microraptor Xu et al, 2000
Species
M. zhaoianus (type) M. gui Xu et al, 2003

Microraptor ("small thief") is a genus of small, dromaeosaurid dinosaur known from well-preserved fossil remains recovered from Liaoning, China, and dating from the early Cretaceous Period (Barremian stage), 130-125.5 million years ago. Like Archaeopteryx, it demonstrates the close evolutionary relationship between birds and dinosaurs, for it had long pennaceous feathers on its limbs and tail. Two species have been named, M. zhaoianus and M. gui. It has recently been suggested that all of the specimens belong to a single species, which is properly called M. zhaoianus. Cryptovolans, another four-winged dromaeosaur, may also be a species of Microraptor.^[1] The Early Cretaceous (timestratigraphic name) or the Lower Cretaceous (logstratigraphic name), is the earlier of the two major divisions of the Cretaceous period. ... Image File history File links Download high resolution version (1171x601, 112 KB) ファイルの概要 dinosaur: Microraptor gui Licensing File links The following pages link to this file: Dinosaur ... Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. ... For other uses, see Animal (disambiguation). ... Typical Classes See below Chordates (phylum Chordata) are a group of animals that includes the vertebrates, together with several closely related invertebrates. ... Subclasses Anapsida Diapsida Synonyms Reptilia Laurenti, 1768 Reptiles are tetrapods and amniotes, animals whose embryos are surrounded by an amniotic membrane, and members of the class Sauropsida. ... Orders & Suborders Saurischia Sauropodomorpha Theropoda Ornithischia Thyreophora Ornithopoda Marginocephalia Dinosaurs were vertebrate animals that dominated the terrestrial ecosystem for over 160 million years, first appearing approximately 230 million years ago. ... Groups Sauropodomorpha    Saturnalia    Prosauropoda    Sauropoda Theropoda    Eoraptor    Herrerasauridae    Ceratosauria    Tetanurae       Aves(extant) Saurischians (from the Greek Saurischia meaning lizard hip) are one of the two orders/branches of dinosaurs. ... Subdivisions ?Eoraptor Herrerasauria Coelophysoidea Ceratosauria Cryolophosaurus Spinosauridae Carnosauria Coelurosauria Theropods (beast foot) are a group of bipedal saurischian dinosaurs. ... Genera Achillobator Adasaurus Atrociraptor Bambiraptor Buitreraptor Cryptovolans Deinonychus Dromaeosaurus Dromaeosauroides Graciliraptor Microraptor Neuquenraptor Pyroraptor Rahonavis Saurornitholestes Sinornithosaurus Tsaagan Unenlagia Utahraptor Variraptor Velociraptor Dromaeosaurids, raptors or members of the family Dromaeosauridae (running lizards from Greek dromeus (δρομευς) meaning runner and sauros (σαυρος) meaning lizard) are theropod dinosaurs. ... Xu Xing, of the Chinese Institute of Vertebrate Paleontology and Paleoanthropology(IVPP) in Beijing, is a famed Chinese paleontologist who has named many dinosaurs, including the new Jurassic Ceratopsian Yinlong and feathered relative of Tyrannosaurus, Guanlong. ... The hierarchy of scientific classification. ... A type species fixes the name of a genus (or of a taxon in a rank lower than genus). ... Xu Xing, of the Chinese Institute of Vertebrate Paleontology and Paleoanthropology(IVPP) in Beijing, is a famed Chinese paleontologist who has named many dinosaurs, including the new Jurassic Ceratopsian Yinlong and feathered relative of Tyrannosaurus, Guanlong. ... For other uses, see Genus (disambiguation). ... Genera Achillobator Adasaurus Bambiraptor Cryptovolans Dromaeosaurus Deinonychus Gracilraptor Microraptor Pyroraptor Saurornitholestes Sinornithosaurus Utahraptor Variraptor Velociraptor Among the dinosaurs, the Dromaeosaurids or Dromaeosauridae (running lizards) were fast and agile dominant carnivores throughout the Cretaceous period. ... Orders & Suborders Saurischia Sauropodomorpha Theropoda Ornithischia Thyreophora Ornithopoda Marginocephalia Dinosaurs were vertebrate animals that dominated the terrestrial ecosystem for over 160 million years, first appearing approximately 230 million years ago. ...   (Simplified Chinese: ; Traditional Chinese: ; pinyin: Liáoníng) is a northeastern province of the Peoples Republic of China. ... // The Cretaceous Period is one of the major divisions of the geologic timescale, reaching from the end of the Jurassic Period (i. ... A geologic period is a subdivision of geologic time that divides an era into smaller timeframes. ... The Barremian faunal stage was a period of geological time between 117 and 113 million years ago. ... Mega-annum, usually abbreviated as Ma, is a unit of time equal to one million years. ... Species A. lithographica Meyer, 1861 (type) Synonyms See below Archaeopteryx (from Ancient Greek archaios meaning ancient and pteryx meaning feather or wing; pronounced Ar-kay-op-ter-iks ) is the earliest and most primitive known bird to date. ... For other uses, see Bird (disambiguation). ... Pennaceous feathers are also known as contour feathers and are present in most modern birds and in some species of maniraptoran dinosaurs. ... Cryptovolans pauli is a 90 cm long feathered dromaeosaurid dinosaur recently discovered in the Jiufotang site, China. ...

Description

At 55-77 cm (1.8-2.5 ft) long from its nose to the tip of its tail, Microraptor was among the smallest known dinosaurs. Aside from its extremely small size, Microraptor was among the first non-avian dinosaurs discovered with the impressions of feathers and wings. Three specimens of M. zhaoianus have been described in detail, in addition to six specimens of M. gui described by Xu et al. in 2003, from which most feather impressions are known. Unusual even among early birds and feathered dinosaurs, Microraptor is one of the few known bird precursors to sport long flight feathers on its feet as well as its forearms and hands. Their bodies had a thick covering of feathers, with a diamond-shaped fan on the end of the tail (possibly for added stability during flight). Some specimens demonstrate a raised feather "crest" on the head, similar to some modern birds, like the Pileated Woodpecker. Bands of dark and light present on some specimens may indicate color patterns present in life. Several anatomical features found in Microraptor, such as a combination of unserrated and partially serrated teeth with constricted 'waists', and unusually long upper arm bones, are shared with both primitive avians and primitive troodontids. Microraptor is particularly similar to the basal troodontid Sinovenator; in their 2002 description of two M. zhaoianus specimens, Hwang et al. note that this is not particularly surprising, given that both Microraptor and Sinovenator are very primitive members of two closely related groups, and both are close to the deinonychosaurian split between dromaeosaurids and troodontids.^[2] Size has been one of the most interesting aspects of dinosaur science to the general public. ... The word Avian can refer to different things: .. Most commonly it is used referring to the class of animals named birds. Avians are a fantasy race in several fantasy settings. ... Binomial name Dryocopus pileatus (Linnaeus, 1758) The Pileated Woodpecker (Dryocopus pileatus) is a very large North American woodpecker. ... Genera See text. ... Binomial name Sinovenator changiae Xu, et al, 2002 Sinovenator was a genus of dinosaur from the Early Cretaceous. ... Families Dromaeosauridae Troodontidae The Deinonychosauria were a successful clade of theropods in the Cretaceous period. ...

Paleobiology

Model of a gliding Microraptor gui

Image File history File linksMetadata Amnh30. ... Image File history File linksMetadata Amnh30. ...

Wings

Like its close relative Cryptovolans (possibly a junior synonym of Microraptor), Microraptor had two sets of wings, on both its fore- and hind legs (close studies of the Berlin specimen of the primitive bird Archaeopteryx show that it too, had flight feathers on its hind legs, albeit shortened). The long feathers on the legs of Microraptor were true flight feathers as seen in modern birds, with asymmetrical vanes on the arm, leg, and tail feathers. As in bird wings, Microraptor had both primary (anchored to the hand) and secondary (anchored to the arm) flight feathers. This standard wing pattern was mirrored on the hind legs, with flight feathers anchored to the upper foot bones as well as the upper and lower leg. It had been proposed by Chinese scientists that the animal glided, and probably lived in trees, pointing to the fact that wings anchored to the feet of Microraptor would have hindered their ability to run on the ground, and suggest that all primitive dromaeosaurids may have been arboreal.^[3] Cryptovolans pauli is a 90 cm long feathered dromaeosaurid dinosaur recently discovered in the Jiufotang site, China. ... Species A. lithographica Meyer, 1861 (type) Synonyms See below Archaeopteryx (from Ancient Greek archaios meaning ancient and pteryx meaning feather or wing; pronounced Ar-kay-op-ter-iks ) is the earliest and most primitive known bird to date. ... For other uses, see Bird (disambiguation). ...

Sankar Chatterjee determined in 2005 that, in order for the creature to glide or fly, the wings must have been split-level (like a biplane) and not overlayed (like a dragonfly), and that the latter posture would have been anatomically impossible. Using this biplane model, Chatterjee was able to calculate possible methods of gliding, and determined that Microraptor most likely employed a phugoid style of gliding--launching itself from a perch, the animal would have swooped downward in a deep 'U' shaped curve and then lifted again to land on another tree. The feathers not directly employed in the biplane wing structure, like those on the tibia and the tail, could have been used to control drag and alter the flight path, trajectory, etc. The orientation of the hind wings would also have helped the animal control its gliding flight. Chatterjee also used computer algorithms that test animal flight capacity to test whether or not Microraptor was capable of true, powered flight, in addition to passive gliding. The resulting data showed that Microraptor did have the requirements to sustain level powered flight, so it is theoretically possible that the animal flew on occasion in addition to gliding.^[4] Sankar Chatterjee is a paleontologist, and is the Paul W. Horn Professor of Geosciences at Texas Tech University and Curator of Paleontology at the Museum of Texas Tech University. ... Hs123 biplane. ... This article is about the insect. ... A phugoid is an aircraft motion where the vehicle pitches up and climbs, and then pitches down and descends, accompanied by speeding up and slowing down as it goes uphill and downhill. ...

Cast of the holotype specimen of Microraptor gui

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Ground movement

Some paleontologists have suggested that feathered dinosaurs used their wings to parachute from trees, possibly in order to attack or ambush prey on the ground, as a precursor to gliding or true flight. In their 2007 study, Chatterjee and Templin tested this hypothesis as well, and found that the combined wing surface of Microraptor was too narrow to successfully parachute to the ground without injury from any significant height. However, the authors did leave open the possibility that Microraptor could have parachuted short distances, as between closely spaced tree branches.

Chatterjee and Templin also ruled out the possibility of a ground-based takeoff. Microraptor lacked the necessary adaptations in its shoulder joint to lift its front wings high enough vertically to generate lift from the ground, and the authors argued that a ground-based takeoff would have damaged flight feathers on the feet. This leaves only the possibility of launching from an elevated perch, and the authors noted that even modern birds do not need to use excess power when launching from trees, but use the downward-swooping technique they found in Microraptor.^[4]

Implications

The unique wing arrangement found in Microraptor raised the question of its importance to the origin of flight in modern birds--did avian flight go through a four-winged stage, or were four-winged gliders like Microraptor an evolutionary side-branch that did not leave descendants? As early as 1915, some scientists had argued that the evolution of bird flight may have gone through a four-winged (or tetrapteryx) stage.^[5] Chatterjee and Templin did not take a strong stance on this possibility, noting that both a conventional interpretation and a tetrapteryx stage are equally possible. However, based on the presence of unusually long leg feathers in various feathered dinosaurs, Archaeopteryx, and some modern birds such as raptors, as well as the discovery of Pedopenna (another dinosaur with long primary feathers on its feet), the authors argued that the current body of evidence, both from morphology and phylogeny, suggests that bird flight did shift at some point from shared limb dominance to front-limb dominance, and that all modern birds may have evolved from four-winged ancestors, or at least ancestors with unusually long leg feathers relative to the modern configuration.^[4] Pedopenna daohugouensis (Xu & Zhang 2005) was a small eumaniraptoran dinosaur from the Late Jurassic from the Daohugou beds in China. ...

Naming

Main article: Archaeoraptor

The naming of Microraptor is 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 unrelated feathered dinosaur species assembled from multiple specimens in China and smuggled to the USA for sale. After the forgery was revealed by 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 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.^[6] However, Xu had discovered the remainder 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.^[7] Archaeoraptor was a fossil believed to be an intermediary between dinosaurs and birds, but proved to be an archaeological forgery. ... Xu Xing, of the Chinese Institute of Vertebrate Paleontology and Paleoanthropology(IVPP) in Beijing, is a famed Chinese paleontologist who has named many dinosaurs, including the new Jurassic Ceratopsian Yinlong and feathered relative of Tyrannosaurus, Guanlong. ... Beijing (Chinese: 北京; pinyin: BÄ›ijÄ«ng; Wade-Giles: Peiching or Pei-ching; IPA: ; literally Northern capital;  ), a metropolis in northern China, is the capital of the Peoples Republic of China (PRC). ... The Institute of Vertebrate Paleontology and Paleoanthropology (abbreviated to IVPP) is a prominent research institution and collections repository for Chinese fossils, including many dinosaur and pterosaur specimens (many from the Yixian Formation). ... Storrs Lovejoy Olson (born April 3, 1944 in Chicago, Illinois) is an American biologist and ornithologist from the Smithsonian Institution. ... Inside the National Museum of Natural History, underneath the rotunda. ... The Smithsonian Institution Building or Castle on the National Mall serves as the Institutions headquarters. ...

Since the two names designate the same individual as the type specimen, Microraptor zhaoianus is a junior objective synonym of Archaeoraptor liaoningensis and the latter, if valid, has priority. So, according to some interpretations of the International Code of Zoological Nomenclature, the valid name for this dinosaur probably is Archaeoraptor liaoningensis Olson 2000. However, there is some doubt whether Olson in fact succeeded in meeting all the formal requirements for establishing a new taxon. Most paleontologists are unwilling to use the name Archaeoraptor regardless of the precise legal status of the name. This is firstly because that name is strongly associated with the fraud and the National Geographic scandal and secondly because they view Olson's use of the name as attempted nomenclatural sabotage and do not want to support it. The name Microraptor zhaoianus Xu et al., 2000 has therefore almost attained universal currency. Type specimens When a new species is discovered, more important than creating a new and unique name for the species is developing a reasonably detailed description. ... Look up Synonym on Wiktionary, the free dictionary Synonyms (in ancient Greek syn συν = plus and onoma όνομα = name) are different words with similar or identical meanings. ... The International Code of Zoological Nomenclature (ICZN) is a set of rules in zoology that have one fundamental aim: to provide the maximum universality and continuity in classifying all animals according to taxonomic judgment. ...

Species list

So far, six virtually complete skeletons of Microraptor have been found in Liaoning, China in 2001 and 2002.   (Simplified Chinese: ; Traditional Chinese: ; pinyin: Liáoníng) is a northeastern province of the Peoples Republic of China. ... Year 2001 (MMI) was a common year starting on Monday (link displays the 2001 Gregorian calendar). ... Also see: 2002 (number). ...

• Family: Dromaeosauridae
  • Clade Microraptoria
    • Genus: Microraptor
      • Microraptor zhaoianus
      • Microraptor gui

Note: Cryptovolans pauli, which has the same four-wing body plan as M. gui, may also be a species of Microraptor. Senter et al. 2004 found that M. zhaoianus, M. gui, and C. pauli are all the same species (M. zhaoianus). Binomial name Cryptovolans pauli Czerkas , 2002 Cryptovolans is a 90 cm long feathered theropod dinosaur discovered in the Jiufotang site, China. ...

In popular culture

Prehistoric Parks Microraptor feeding.

• Microraptor featured prominently in the third episode of the 2006 mockumentary television series Prehistoric Park. In the episode, Microraptor were shown flocking down from trees to feast on worms and insects that were brought to the surface by the passage of giant titanosaurs.
• A Microraptor gui named Guido appeared in the animated film The Land Before Time XII: The Great Day of the Flyers.

Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Prehistoric Park is a 6-part television series in documentary style, from Impossible Pictures Limited, (the makers of Walking with Dinosaurs) which premiered on ITV on 22 July 2006 and on Animal Planet on 29 October 2006. ... This article or section cites very few or no references or sources. ... Prehistoric Park is a 6-part television series in documentary style, from Impossible Pictures Limited, (the makers of Walking with Dinosaurs) which premiered on ITV on 22 July 2006 and on Animal Planet on 29 October 2006. ... Genera and Families Andesaurus Family Titanosauridae Epachthosaurus Argentinosaurus Antarctosaurus Malawisaurus Argyrosaurus Gondwanatitan Aeolosaurus Baurutitan Trigonosaurus Alamosaurus Isisaurus Subfamily Nemegtosaurinae Subfamily Saltasaurinae For the Titanosaurus featured in the Godzilla film series, see Titanosaurus (Godzilla). ... Screen shot from The Land Before Time. ...

References

External links

Wikispecies has information related to:

Microraptor

• A model of Microraptor/Cryptovolans pauli by Boban Filipovic

• Jacqui Hayes: Bird wings evolved from biplane dinosaurs COSMOS magazine

Dinosaurs Portal