Xiaotingia

Chordata

Xiaotingia
Temporal range: Late Jurassic, 160 Ma
Type specimen
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Superorder: Dinosauria
Order: Saurischia
Suborder: Theropoda
Family: Troodontidae
Genus: Xiaotingia
Xu et al., 2011
Species: X. zhengi
Binomial name
Xiaotingia zhengi
Xu et al., 2011

Xiaotingia is a genus of bird-like theropod dinosaur from early Late Jurassic deposits of western Liaoning, China, containing a single species, Xiaotingia zhengi.[1]

Contents

Discovery

Xiaotingia is known from the holotype STM 27-2, an articulated and nearly complete skeleton including the skull. It was probably collected in the Linglongta area, Jianchang, from the Tiaojishan Formation.[1]

Etymology

Xiaotingia was first named by Xu Xing, You Hailu, Du Kai and Han Fenglu in 2011 and the type species is Xiaotingia zhengi. Generic name and specific name together honour Zheng Xiaoting.[1]

Phylogeny

An initial cladistic analysis by Xu et al. showed that Xiaotingia formed a clade with Archaeopteryx, Dromaeosauridae and Troodontidae to the exclusion of other groups traditionally seen as birds. Xu et al. therefore (re)defined the concepts of Deinonychosauria and Avialae to the extent that Archaeopteryx and Xiaotingia belonged to the Deinonychosauria and Archaeopteryx no longer was an avialan.[1] This led to popular reports that "Archaeopteryx is no longer a bird",[2] though Xu et al. noted that there are several competing definitions of the clade Aves currently in use, pointing out that their definitions are compatible with a traditional Aves with Archaeopteryx as a specifier.[1] However, this was challenged by a more thorough analysis published several months later, in which Archaeopteryx was again recovered as an avialan, while Xiaotingia remained closely allied to Anchiornis within the Troodontidae.[3]

Cladogram after Xu et al., 2011:[1]



Oviraptorosauria


Paraves
Avialae
Scansoriopterygidae

Epidendrosaurus



Epidexipteryx





Jeholornis




Sapeornis




Confuciusornis



Ornithothoraces






Deinonychosauria


Troodontidae



Dromaeosauridae



Archaeopterygidae


Archaeopteryx



Wellnhoferia





Anchiornis



Xiaotingia







References

  1. ^ a b c d e f Xing Xu, Hailu You, Kai Du and Fenglu Han (28 July 2011). "An Archaeopteryx-like theropod from China and the origin of Avialae". Nature 475 (7357): 465–470. doi:10.1038/nature10288. PMID 21796204. http://www.nature.com/nature/journal/v475/n7357/full/nature10288.html. 
  2. ^ http://www.bbc.co.uk/news/science-environment-14307985
  3. ^ Lee, M.S.Y. and Worthy, T.H. (2011). "Likelihood reinstates Archaeopteryx as a primitive bird. Biology Letters, published online before print October 26, 2011, doi:10.1098/rsbl.2011.0884