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Paravians
Temporal range: Late Jurassic–Recent, 160–0 Ma
Fossil of complete Archaeopteryx, including indentations of feathers on wings and tail.
Fossil specimen of Archaeopteryx lithographica
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauria
Clade: Pennaraptora
Clade: Paraves
Sereno, 1997
Subgroups
Synonyms
  • Eumaniraptora
    Padian, Hutchinson & Holtz, 1997

Paraves is a branch-based clade defined to include all dinosaurs which are more closely related to birds than to oviraptorosaurs. Paravians comprises two major sub-groups: Avialae, including Jeholornis and flying birds, and Deinonychosauria, which includes the dromaeosaurids and troodontids.

The ancestral paravian is a hypothetical animal; the first common ancestor of birds, dromaeosaurids, and troodontids which was not also ancestral to oviraptorosaurs. Little can be said with certainty about this animal. The work of Turner et al. (2007) suggested that the ancestral paravian could not glide or fly, and that it was most likely small (around 65 centimeters long and 600–700 grams in mass).[1] But the work of Xu et al. (2003), (2005) and Hu et al. (2009) provide examples of basal and early paravians with four wings, including members of the Avialae (Pedopenna), Dromaeosauridae (Microraptor), and Troodontidae (Anchiornis).[2][3][4]

Classification

The name Paraves was coined by Paul Sereno in 1997.[5] The clade was defined by Sereno in 1998 as a branch-based clade containing all Maniraptora closer to Neornithes (which includes all the birds living in the world today) than to Oviraptor.[6]

Also in 1997, a node-based clade called Eumaniraptora ("true maniraptorans") was named by Padian, Hutchinson and Holtz. They defined their clade to include only birds and deinonychosaurs. However, because there are currently no known species of paravian which are not also eumaniraptoran, these groups are considered to be synonyms.

The cladogram presented below follows a study by Zhang et al. 2008.[7]

Paraves
Avialae

Epidendrosaurus (=Scansoriopteryx)


Aves

Archaeopteryx




Jeholornis


Avebrevicauda

Sapeornis


Pygostylia

Confuciusornis


Ornithothoraces

Enantiornithes


Ornithurae

Yanornis




Hesperornis



Modern Birds










Deinonychosauria
Troodontidae

Sinovenator




Mei



Troodon




Dromaeosauridae


Unenlagia




Microraptoria

Bambiraptor



Microraptor



Eudromaeosauria

Velociraptor




Deinonychus




Dromaeosaurus









A 2011 report on the discovery of a new Archaeopteryx-like theropod Xiaotingia zhengi suggests that including it in a cladistic analysis shifts Archaeopteryx and similar species from the Avialae into the Deinonychosauria. Statistical support for the hypothesis is limited, and the authors say that it needs to be confirmed by further investigation.[8]

References

  1. ^ Turner, Alan H.; Pol, Diego; Clarke, Julia A.; Erickson, Gregory M.; Norell, M. (2007). "A basal dromaeosaurid and size evolution preceding avian flight". Science. 317 (5843): 1378–1381. Bibcode:2007Sci...317.1378T. PMID 17823350. doi:10.1126/science.1144066. 
  2. ^ Hu, Dongyu, Lianhi, Hou, Zhang, Lijun, Xu, Xing. (2009) A pre-Archaeopteryx troodontid theropod from China with long feathers on the metatarsus. Nature, Vol 461 1 October 2009, pp. 640-643. doi:10.1038/nature08322.
  3. ^ Xing, X.; Zhou, Z.; Wang, X.; Kuang, X.; Zhang, F.; Du, X. (2003). "Four-winged dinosaurs from China". Nature. 421 (6921): 335–340. PMID 12540892. doi:10.1038/nature01342. 
  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. PMID 15685441. doi:10.1007/s00114-004-0604-y. 
  5. ^ Sereno, P. C., 1997, "The origin and evolution of dinosaurs", Annual Review of Earth & Planetary Sciences 25:435- 489. (21)
  6. ^ Sereno, P. C., 1998, "A rationale for phylogenetic definitions, with application to the higher level taxonomy of Dinosauria", Neues Jahrbuch für Geologie und Paläontologie Abhandlungen 210:41-83. (23)
  7. ^ Zhang, F.; Zhou, Z.; Xu, X.; Wang, X.; Sullivan, C. (2008). "A bizarre Jurassic maniraptoran from China with elongate ribbon-like feathers". Nature. 455 (7216): 1105–1108. Bibcode:2008Natur.455.1105Z. PMID 18948955. doi:10.1038/nature07447. 
  8. ^ Xu, Xing; You, Hailu; Du, Kai; Han, Fenglu (2011). "An Archaeopteryx-like theropod from China and the origin of Avialae". Nature. 475 (7357): 465–470. PMID 21796204. doi:10.1038/nature10288. 
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