Microraptoria

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title: "Microraptoria" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["microraptoria", "dinosaur-clades", "early-cretaceous-dinosaurs", "dinosaurs-of-asia"] description: "Extinct clade of dinosaurs" topic_path: "general/microraptoria" source: "https://en.wikipedia.org/wiki/Microraptoria" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Extinct clade of dinosaurs ::

| name = Microraptorians | fossil_range = Possible Late Cretaceous records | image = Microraptor gui holotype.png | image_caption = Fossil specimen of a Microraptor, with white arrows pointing at preserved feathers | taxon = Microraptoria | authority = Senter et al., 2004 | subdivision_ranks = Genera | subdivision =

• Changyuraptor
• Daurlong?
• Graciliraptor
• Hesperonychus?
• Microraptor
• Shanag?
• Sinornithosaurus
• Tianyuraptor?
• Wulong
• Zhenyuanlong?
• Zhongjianosaurus | synonyms =
• Microraptorinae Senter et al., 2004
• Microraptorini Senter et al., 2004 Microraptoria (Greek, μίκρος, mīkros: "small"; Latin, raptor: "one who seizes") is a clade of basal dromaeosaurid theropod dinosaurs. Definitive microraptorians lived during the Barremian to Aptian stages of the Early Cretaceous in China. Probable microraptorian ichnotaxon Dromaeosauriformipes was discovered from the Jinju Formation of South Korea, and some fragmentary Late Cretaceous paravian fossils in North America have been described as putative members of this clade. Many are known for long feathers on their legs and may have been semiarboreal powered fliers, some of which were even capable of launching from the ground. Most microraptorians were relatively small; adult specimens of Microraptor range between 77 -) and weigh up to 1 kg, making them some of the smallest known non-avialan dinosaurs.

Description

::figure[src="https://upload.wikimedia.org/wikipedia/commons/c/c1/Sinornithosaurus_Dave_NGMC91.jpg" caption="NGMC 91, believed to be a juvenile specimen of ''[[Sinornithosaurus]]''"] ::

Microraptorians were a group of basal dromaeosaurids (popularly known as "raptors") with slender proportions and long limbs. All definitive members have been found in the Yixian and Jifuotang Formations of Liaoning County of China, so they're referred to as "Liaoning dromaeosaurids" by some researchers. These formations (collectively known as the Jehol Biota) have been dated to the early Cretaceous and at that time would have been part of a temperate wetland ecosystem threatened by frequent volcanic eruptions. Like other dromaeosaurids, microraptorians were carnivores with relatively large, serrated teeth and a hyperextendable second toe equipped with a curved claw. Some fragmentary paravian fossils from the Late Cretaceous (Campanian-Maastrichtian stages) of North America have been putatively suggested as microraptorians, though their taxonomic referral are considered controversial, namely Hesperonychus being recovered as an avialan in one phylogenetic analysis.

Size and proportions

::figure[src="https://upload.wikimedia.org/wikipedia/commons/d/d8/Changyuraptor.png" caption="A life restoration of ''[[Changyuraptor]]'', a large "four-winged" microraptorine"] ::

Most microraptorians were small dinosaurs, with taxa such as Microraptor and especially Zhongjianosaurus being among the smallest nonavian dinosaurs known. However, some microraptorians, such as Tianyuraptor and Changyuraptor, were larger and similar to other dromaeosaurids in size. Many microraptorians also had long and robust arms and legs, in contrast to the stockier eudromaeosaurs, although long arms are not universal to the group, since the basal microraptorian Tianyuraptor had unusually short arms by dromaeosaurid standards. Considering this, the small size and long wings of some microraptorians likely are examples of convergent evolution with other small paravians and early birds such as Anchiornis and Archaeopteryx.

Feathers

The fossilization conditions of the Jehol group are very accommodating to the preservation of soft structures in fossils, and as a result, many microraptorians have been preserved with a covering of feathers. Not only have long, advanced feathers been preserved on the arms and tails of many specimens, but a few species even have long feathers on their legs. This condition has also been seen in other paravians such as Anchiornis, and has caused these kinds of dinosaurs to be labelled as "four-winged dinosaurs". The largest known "four-winged" dinosaur, Changyuraptor, is a microraptorian. Some microraptorians such as Microraptor possibly were able to use these wings to glide or take off from the ground, and perhaps even capable of powered flight.

Characteristic features

Sources:

Microraptorines can be distinguished from other dromaeosaurids by these features:

• A maxilla laterally sculpted by small pits
• A very short manual phalanx III-2
• A shortened first digit of the hand
• A splatulate (rounded) pubic symphysis
• A metatarsal III with a pinched proximal end
• A slender metatarsal II In addition, several features are present in microraptorines with the exception of Tianyuraptor, which is believed to be a basal member of the clade:
• A large oval fenestra in the coracoid
• Significantly shortened penultimate manual phalanges
• The posterior end of the ilium extending ventral to the ischial peduncle
• Lateral projections halfway down the pubis
• A strongly anteriorly curved pubic shaft

Classification

::figure[src="https://upload.wikimedia.org/wikipedia/commons/b/bf/Microraptor_recon.png" caption="Artist's reconstruction of ''[[Microraptor]]''"] ::

Microraptoria is usually classified as a clade of Dromaeosauridae, though some consider the group to be outside the dromaeosaurid family. Senter and colleagues expressly coined the name without the subfamily suffix -inae to avoid perceived issues with erecting a traditional family-group taxon, should the group be found to lie outside the Dromaeosauridae proper. Sereno offered a revised definition of the subgroup containing Microraptor to ensure that it would fall within the Dromaeosauridae, and erected the subfamily Microraptorinae, attributing it to Senter et al., though this usage has only appeared on his online TaxonSearch database and has not been formally published.

The cladogram below follows a 2012 analysis by paleontologists Phil Senter, James I. Kirkland, Donald D. DeBlieux, Scott Madsen and Natalie Toth. |label1=Dromaeosauridae |1={{clade |1=Xiaotingia |2={{clade |1=Unenlagiinae |2={{clade |1=Shanag |2={{clade |label1=Eudromaeosauria |1={{clade |1=Saurornitholestinae |2={{clade |1=Velociraptorinae |2=Dromaeosaurinae }} }} |label2=Microraptoria |2={{clade |1=Tianyuraptor |2={{clade |1=Hesperonychus |2={{clade |1={{clade |1=Microraptor sp. |2={{clade |1=Microraptor gui |2=Microraptor zhaoianus }} }} |2={{clade |1=Cryptovolans |2=Graciliraptor |3=Sinornithosaurus }} }} }} }} }} }} }} }} }}

In a 2024 paper which reported the smallest known juvenile specimen of Microraptor, Wang and Pei included microraptorians and eudromaeosaurians within a new clade Serraraptoria.

References

• "Expand and Life history of a basal bird: morphometrics of the Early Cretaceous Confuciusornis" Luis M Chiappe, Jesús Marugán-Lobón, Shu'an Ji & Zhonghe Zhou (2008)

References

1. (2020). "Pennaraptoran Theropod Dinosaurs Past Progress and New Frontiers". Bulletin of the American Museum of Natural History.
2. "辽西下白垩统热河群一新微型驰龙类恐龙和热河生物群驰龙类的生态位分化----中国科学院古脊椎动物与古人类研究所".
3. (2018-11-15). "Smallest known raptor tracks suggest microraptorine activity in lakeshore setting". Scientific Reports.
4. (2024). "Theropod trackways as indirect evidence of pre-avian aerial behavior". Proceedings of the National Academy of Sciences of the United States of America.
5. (2016). "The wings before the bird: an evaluation of flapping-based locomotory hypotheses in bird antecedents". PeerJ.
6. 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.]
7. (2007). "Biplane wing planform and flight performance of the feathered dinosaur ''Microraptor gui''". Proceedings of the National Academy of Sciences.
8. (2015). "A large, short-armed, winged dromaeosaurid (Dinosauria: Theropoda) from the Early Cretaceous of China and its implications for feather evolution". Scientific Reports.
9. (2008). "On the horizon of ''Protopteryx'' and the early vertebrate fossil assemblages of the Jehol Biota". Chinese Science Bulletin.
10. (2019-07-10). "A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight". PeerJ.
11. Brownstein, C. D.. (2024). "A juvenile bird with possible crown-group affinities from a dinosaur-rich Cretaceous ecosystem in North America". BMC Ecology and Evolution.
12. (2010-01-22). "A short-armed dromaeosaurid from the Jehol Group of China with implications for early dromaeosaurid evolution". Proceedings of the Royal Society of London B: Biological Sciences.
13. (2014-07-15). "A new raptorial dinosaur with exceptionally long feathering provides insights into dromaeosaurid flight performance". Nature Communications.
14. (2013). "Avian ancestors. A review of the phylogenetic relationships of the theropods Unenlagiidae, Microraptoria, ''Anchiornis'' and Scansoriopterygidae". SpringerBriefs in Earth System Sciences.
15. (2020). "High flyer or high fashion? A comparison of flight potential among small-bodied paravians". Bulletin of the American Museum of Natural History.
16. (20 February 2024). "Functional constraints on the number and shape of flight feathers". Proceedings of the National Academy of Sciences.
17. (2009-03-31). "A microraptorine (Dinosauria–Dromaeosauridae) from the Late Cretaceous of North America". Proceedings of the National Academy of Sciences.
18. (2013). "Discussion". Springer Netherlands.
19. (2004). "Systematics and evolution of Dromaeosauridae (Dinosauria, Theropoda)". Bulletin of the Gunma Museum of Natural History.
20. Sereno, P. C. 2005. [http://www.taxonsearch.org/Archive/stem-archosauria-1.0.php Stem Archosauria—TaxonSearch] {{webarchive. link. (2009-01-15 [version 1.0, November 7, 2005)
21. (2012). "New Dromaeosaurids (Dinosauria: Theropoda) from the Lower Cretaceous of Utah, and the Evolution of the Dromaeosaurid Tail". PLOS ONE.
22. (2024). "The smallest known specimen of ''Microraptor'' (Dinosauria: Dromaeosauridae) from the Jiufotang Formation in northeastern China". Historical Biology: An International Journal of Paleobiology.

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