Pedopenna

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Pedopenna
Temporal range: Late Jurassic, 164  Ma
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Pedopenna.png
Reconstruction as an anchiornithid
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Clade: Paraves
Family: Anchiornithidae
Genus: Pedopenna
Xu & Zhang, 2005
Species:
P. daohugouensis
Binomial name
Pedopenna daohugouensis
Xu & Zhang, 2005

Pedopenna (meaning "foot feather") is a genus of small, feathered, maniraptoran dinosaur from the Daohugou Beds in China. It is possibly older than Archaeopteryx , though the age of the Daohugou Beds where it was found is debated. A majority of studies suggest that beds probably date from between the late Middle Jurassic (168 million years ago) and early Late Jurassic Period (164-152 million years ago). [1]

The name Pedopenna refers to the long pennaceous feathers on the metatarsus; daohugouensis refers to the locality of Daohugou, where the holotype was found. [2] Pedopenna daohugouensis probably measured 1 meter (3 ft) or less in length, but since this species is only known from the hind legs, the actual length is difficult to estimate. Pedopenna was originally classified as a paravian, the group of maniraptoran dinosaurs that includes both deinonychosaurs and avialans (the lineage including modern birds), but some scientists have classified it as a true avialan more closely related to modern birds than to deinonychosaurs. [3] More recently, it has been recovered as a scansoriopterygid. [4] Lately it was placed to the family Anchiornithidae. [5]

Description

The feet of Pedopenna resembled those of the related troodontids and dromaeosaurids (which together form the group Deinonychosauria), though were overall more primitive. In particular, the second toe of Pedopenna was not as specialized as in deinonychosaurs. While Pedopenna did have an enlarged claw and slightly shortened second toe, it was not as highly developed as the strongly curved, sickle-like claws of its relatives. [2]

Xu Xing and Zhang Fucheng, who interpreted the Daohugou fossil beds where Pedopenna was found as mid to late Jurassic in age, used the presence of such a primitive member of the avian lineage, in combination with many primitive members of closely related lineages there, to support the idea that birds originated in Asia. [2]

Feathers

The bird-like characteristics of Pedopenna are further evidence of the dinosaur-bird evolutionary relationship. Apart from having a very bird-like skeletal structure in its legs, Pedopenna was remarkable due to the presence of long pennaceous feathers on the metatarsus (foot). Some deinonychosaurs are also known to have these 'hind wings', but those of Pedopenna differ from those of animals like Microraptor . Pedopenna hind wings were smaller and more rounded in shape. The longest feathers were slightly shorter than the metatarsus, at about 55 mm (2 in) long. Additionally, the feathers of Pedopenna were symmetrical, unlike the asymmetrical feathers of some deinonychosaurs and birds. Since asymmetrical feathers are typical of animals adapted to flying, it is likely that Pedopenna represents an early stage in the development of these structures. While many of the feather impressions in the fossil are weak, it is clear that each possessed a rachis and barbs, and while the exact number of foot feathers is uncertain, they are more numerous than in the hind-wings of Microraptor. Pedopenna also shows evidence of shorter feathers overlying the long foot feathers, evidence for the presence of coverts as seen in modern birds. Since the feathers show fewer aerodynamic adaptations than the similar hind wings of Microraptor, and appear to be less stiff, suggests that if they did have some kind of aerodynamic function, it was much weaker than in deinonychosaurs and birds.[ citation needed ]

Xu and Zhang, in their 2005 description of Pedopenna, suggested that the feathers could be ornamental, or even vestigial. It is possible that a hind wing was present in the ancestors of deinonychosaurs and birds, and later lost in the bird lineage, with Pedopenna representing an intermediate stage where the hind wings are being reduced from a functional gliding apparatus to a display or insulatory function. [2] this theory may be confirmed by the discovery of Serikornis in 2017, an anchiornithid with soft, symmetrical feathers and filaments on parts of the body that were similar to Pedopenna's.

Related Research Articles

<i>Archaeopteryx</i> Extinct genus of bird-like dinosaurs

Archaeopteryx, sometimes referred to by its German name, "Urvogel" is a genus of bird-like dinosaurs. The name derives from the ancient Greek ἀρχαῖος (archaīos), meaning "ancient", and πτέρυξ (ptéryx), meaning "feather" or "wing". Between the late 19th century and the early 21st century, Archaeopteryx was generally accepted by palaeontologists and popular reference books as the oldest-known bird. Older potential avialans have since been identified, including Anchiornis, Xiaotingia, and Aurornis.

<span class="mw-page-title-main">Deinonychosauria</span> Extinct clade of dinosaurs

Deinonychosauria is a clade of paravian dinosaurs which lived from the Late Jurassic to the Late Cretaceous periods. Fossils have been found across the globe in North America, Europe, Africa, Asia, South America, and Antarctica, with fossilized teeth giving credence to the possibility that they inhabited Australia as well. This group of dinosaurs are known for their sickle-shaped toe claws and features in the shoulder bones.

<span class="mw-page-title-main">Dromaeosauridae</span> Family of theropod dinosaurs

Dromaeosauridae is a family of feathered coelurosaurian theropod dinosaurs. They were generally small to medium-sized feathered carnivores that flourished in the Cretaceous Period. The name Dromaeosauridae means 'running lizards', from Greek δρομαῖος (dromaîos), meaning 'running at full speed', 'swift', and σαῦρος (saûros), meaning 'lizard'. In informal usage, they are often called raptors, a term popularized by the film Jurassic Park; several genera include the term "raptor" directly in their name, and popular culture has come to emphasize their bird-like appearance and speculated bird-like behavior.

<i>Caudipteryx</i> Genus of oviraptorosaur dinosaurs

Caudipteryx is a genus of small oviraptorosaur dinosaurs that lived in Asia during the Early Cretaceous, around 124.6 million years ago. They were feathered and extremely birdlike in their overall appearance, to the point that some paleontologists suggested it was a bird. Two species have been described: C. zoui, in 1998, and C. dongi, in 2000.

<i>Microraptor</i> Extinct genus of dinosaurs

Microraptor is a genus of small, four-winged dromaeosaurid dinosaurs. Numerous well-preserved fossil specimens have been recovered from Liaoning, China. They date from the early Cretaceous Jiufotang Formation, 125 to 120 million years ago. Three species have been named, though further study has suggested that all of them represent variation in a single species, which is properly called M. zhaoianus. Cryptovolans, initially described as another four-winged dinosaur, is usually considered to be a synonym of Microraptor.

<span class="mw-page-title-main">Maniraptora</span> Clade of dinosaurs

Maniraptora is a clade of coelurosaurian dinosaurs which includes the birds and the non-avian dinosaurs that were more closely related to them than to Ornithomimus velox. It contains the major subgroups Avialae, Dromaeosauridae, Troodontidae, Oviraptorosauria, and Therizinosauria. Ornitholestes and the Alvarezsauroidea are also often included. Together with the next closest sister group, the Ornithomimosauria, Maniraptora comprises the more inclusive clade Maniraptoriformes. Maniraptorans first appear in the fossil record during the Jurassic Period, and survive today as living birds.

<span class="mw-page-title-main">Coelurosauria</span> Clade of dinosaurs

Coelurosauria is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs.

<i>Jinfengopteryx</i> Theropod dinosaur genus

Jinfengopteryx is a genus of maniraptoran dinosaur. It was found in the Qiaotou Member of the Huajiying Formation of Hebei Province, China, and is therefore of uncertain age. The Qiaotou Member may correlate with the more well-known Early Cretaceous Yixian Formation, and so probably dates to around 122 Ma ago.

<i>Scansoriopteryx</i> Extinct genus of dinosaurs

Scansoriopteryx is a genus of maniraptoran dinosaur. Described from only a single juvenile fossil specimen found in Liaoning, China, Scansoriopteryx is a sparrow-sized animal that shows adaptations in the foot indicating an arboreal (tree-dwelling) lifestyle. It possessed an unusual, elongated third finger which may have supported a membranous wing, much like the related Yi qi. The type specimen of Scansoriopteryx also contains the fossilized impression of feathers.

<span class="mw-page-title-main">Scansoriopterygidae</span> Extinct family of dinosaurs

Scansoriopterygidae is an extinct family of climbing and gliding maniraptoran dinosaurs. Scansoriopterygids are known from five well-preserved fossils, representing four species, unearthed in the Tiaojishan Formation fossil beds of Liaoning and Hebei, China.

<span class="mw-page-title-main">Avialae</span> Clade including all birds and their ancestors

Avialae is a clade containing the only living dinosaurs, the birds. It is usually defined as all theropod dinosaurs more closely related to birds (Aves) than to deinonychosaurs, though alternative definitions are occasionally used.

<span class="mw-page-title-main">Paraves</span> Clade of all dinosaurs that are more closely related to birds than to oviraptorosaurs

Paraves are a widespread group of theropod dinosaurs that originated in the Middle Jurassic period. In addition to the extinct dromaeosaurids, troodontids, anchiornithids, and possibly the scansoriopterygids, the group also contains the avialans, which include diverse extinct taxa as well as the over 10,000 species of living birds. Basal members of Paraves are well known for the possession of an enlarged claw on the second digit of the foot, which was held off the ground when walking in some species. A number of differing scientific interpretations of the relationships between paravian taxa exist. New fossil discoveries and analyses make the classification of Paraves an active subject of research.

<i>Epidexipteryx</i> Extinct genus of dinosaurs

Epidexipteryx is a genus of small paravian dinosaurs, known from one fossil specimen in the collection of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing. Epidexipteryx represents the earliest known example of ornamental feathers in the fossil record.

<i>Anchiornis</i> Extinct genus of dinosaurs

Anchiornis is a genus of small, four-winged paravian dinosaurs, with only one known species, the type species Anchiornis huxleyi, named for its similarity to modern birds. The Latin name Anchiornis derives from a Greek word meaning "near bird", and huxleyi refers to Thomas Henry Huxley, a contemporary of Charles Darwin.

<i>Xiaotingia</i> Extinct genus of dinosaurs

Xiaotingia is a genus of anchiornithid theropod dinosaur from Middle Jurassic or early Late Jurassic deposits of western Liaoning, China, containing a single species, Xiaotingia zhengi.

<i>Eosinopteryx</i> Extinct genus of dinosaurs

Eosinopteryx is an extinct genus of theropod dinosaurs known to the Late Jurassic epoch of China. It contains a single species, Eosinopteryx brevipenna.

<i>Aurornis</i> Extinct genus of dinosaurs

Aurornis is an extinct genus of anchiornithid theropod dinosaurs from the Jurassic period of China. The genus Aurornis contains a single known species, Aurornis xui. Aurornis xui may be the most basal ("primitive") avialan dinosaur known to date, and it is one of the earliest avialans found to date. The fossil evidence for the animal pre-dates that of Archaeopteryx lithographica, often considered the earliest bird species, by about 10 million years.

<i>Serikornis</i> Extinct genus of dinosaurs

Serikornis is a genus of small, feathered anchiornithid dinosaur from the Upper Jurassic Tiaojishan Formation of Liaoning, China. It is represented by the type species Serikornis sungei.

<span class="mw-page-title-main">Anchiornithidae</span> Extinct family of dinosaurs

Anchiornithidae is a family of small paravian dinosaurs. Anchiornithids have been classified at varying positions in the paravian tree, with some scientists classifying them as a distinct family, a basal subfamily of Troodontidae, members of Archaeopterygidae, or an assemblage of dinosaurs that are an evolutionary grade within Avialae or Paraves.

References

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  2. 1 2 3 4 Xu, X. & Zhang, F. (2005). "A new maniraptoran dinosaur from China with long feathers on the metatarsus". Naturwissenschaften. 92 (4): 173–177. Bibcode:2005NW.....92..173X. doi:10.1007/s00114-004-0604-y. PMID   15685441. S2CID   789908.
  3. Hone D.W.E.; Tischlinger H.; Xu X.; Zhang F. (2010). Farke, Andrew Allen (ed.). "The extent of the preserved feathers on the four-winged dinosaur Microraptor gui under ultraviolet light". PLOS ONE. 5 (2): e9223. Bibcode:2010PLoSO...5.9223H. doi: 10.1371/journal.pone.0009223 . PMC   2821398 . PMID   20169153.
  4. Hartman, Scott; Mortimer, Mickey; Wahl, William R.; Lomax, Dean R.; Lippincott, Jessica; Lovelace, David M. (2019). "A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight". PeerJ. 7: e7247. doi:10.7717/peerj.7247. PMC 6626525. PMID   31333906.
  5. Lefèvre, Ulysse; Cau, Andrea; Hu, Dongyu; Godefroit, Pascal (2020), Foth, Christian; Rauhut, Oliver W. M. (eds.), "Feather Evolution in Pennaraptora", The Evolution of Feathers: From Their Origin to the Present, Fascinating Life Sciences, Cham: Springer International Publishing, pp. 103–118, doi:10.1007/978-3-030-27223-4_7, ISBN   978-3-030-27223-4 , retrieved 2023-07-12