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''Jixiangornis'' is a genus of basal avialan
Hartman ''et al''. (2019), Cau (2020) and Wang ''et al'' (2020) found ''Jixiangornis'' to have been a jeholornithid but not a synonym of ''Jeholornis''.
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{{Taxonbar, from=Q10917354 Avialae Early Cretaceous dinosaurs of Asia Jiufotang fauna Yixian fauna Fossil taxa described in 2002
dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...
s from the Early Cretaceous
The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...
. Like later avialans, it had no teeth, but it also had a long tail, unlike modern bird
Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...
s. Since teeth were still present in some more derived short-tailed avialans, ''Jixiangornis'' seems to have evolved its toothlessness independently of modern birds. The long forelimb (131% of hindlimb length) indicates at least some aerial ability. ''Jixiangornis'' is currently known only from a single specimen, a complete but juvenile skeleton. The fossil was found in the Yixian Formation
The Yixian Formation (; formerly Romanization of Chinese, transcribed as Yihsien Formation or Yixiang Formation) is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans the Barremian stage of the Early Cretaceous. I ...
near Beipiao City, western Liaoning
)
, image_skyline =
, image_alt =
, image_caption = Clockwise: Mukden Palace in Shenyang, Xinghai Square in Dalian, Dalian coast, Yalu River at Dandong
, image_map = Liaoning in China (+all claims hatched).svg
, ...
, China
China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...
.
Classification
The only known species, ''J. orientalis'' ("Oriental bird from the Yixian Formation"), was described in November 2002. Ji ''et al.'' (2002) considered ''Jixiangornis'' capable of stronger flight than either ''Archaeopteryx
''Archaeopteryx'' (; ), sometimes referred to by its German name, "" ( ''Primeval Bird'') is a genus of bird-like dinosaurs. The name derives from the ancient Greek (''archaîos''), meaning "ancient", and (''ptéryx''), meaning "feather" ...
'' or ''Jeholornis
''Jeholornis'' (meaning "Jehol bird") is a genus of avialan dinosaurs that lived between approximately 122 and 120 million years ago during the early Cretaceous Period in China. Fossil ''Jeholornis'' were first discovered in the Jiufotang Formati ...
''. Their phylogenetic tree shows ''Jixiangornis'' forming a clade (called "Euavialae" by Ji ''et al.'') with birds that excludes ''Archaeopteryx'' and ''Jeholornis'' (=''Shenzhouraptor'').
An alternative view was presented by Zhou Zong-He and Zhang Fu-Cheng in 2006. They classified both ''Jixiangornis'' and ''Shenzhouraptor'' as junior synonyms of '' Jeholornis prima'', meaning that ''Jixiangornis'' cannot be more advanced than ''Shenzhouraptor''. This approach, however, was problematical given the numerous differences between ''Jixiangornis'' and ''Shenzhouraptor/Jeholornis'', and a phylogenetic analysis performed in 2014 found that it may actually be more closely related to short-tailed avialans (Pygostylia
Pygostylia is a group of avialans which includes the Confuciusornithidae and all of the more advanced species, the Ornithothoraces.
Definition
The group Pygostylia was intended to encompass all avialans with a short, stubby tail, as opposed t ...
) than to ''Jeholornis'', as originally thought.
Hartman ''et al''. (2019), Cau (2020) and Wang ''et al'' (2020) found ''Jixiangornis'' to have been a jeholornithid but not a synonym of ''Jeholornis''.
References
Sources
* * Zhou, Z.-H. & Zhang, F.-C. (2006): Mesozoic birds of China - A synoptic review. ''Vertebrata PalAsiatica'' 44(1): 74–98PDF fulltext
{{Taxonbar, from=Q10917354 Avialae Early Cretaceous dinosaurs of Asia Jiufotang fauna Yixian fauna Fossil taxa described in 2002