A Jurassic ceratosaur from China helps clarify avian digital homologies

@article{Xu2009AJC,
  title={A Jurassic ceratosaur from China helps clarify avian digital homologies},
  author={Xing Xu and James M. Clark and Jinyou Mo and Jonah N. Choiniere and Catherine A. Forster and Gregory M. Erickson and David W. E. Hone and Corwin Sullivan and David A. Eberth and Sterling J. Nesbitt and Qi Zhao and Rene Hernandez and Chengkai Jia and Fenglu Han and Yu Guo},
  journal={Nature},
  year={2009},
  volume={459},
  pages={940-944}
}
Theropods have traditionally been assumed to have lost manual digits from the lateral side inward, which differs from the bilateral reduction pattern seen in other tetrapod groups. This unusual reduction pattern is clearly present in basal theropods, and has also been inferred in non-avian tetanurans based on identification of their three digits as the medial ones of the hand (I-II-III). This contradicts the many developmental studies indicating II-III-IV identities for the three manual digits… 
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