Limusaurus and bird digit identity
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- Universidad de Chile
- Yale University
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- Document Type:
- Manuscript
- Date:
- Received 06 October 2009 03:05 UTC; Posted 06 October 2009
- Subjects:
- Developmental Biology, Genetics & Genomics, Molecular Cell Biology, Evolutionary Biology
- Abstract:
Limusaurus is a remarkable herbivorous ceratosaur unique among theropods in having digits II, III and IV, with only a small metacarpal vestige of digit I. This raises interesting questions regarding the controversial identity of avian wing digits. The early tetanuran ancestors of birds had tridactyl hands with digital morphologies corresponding to digits I, II & III of other dinosaurs. In bird embryos, however, the pattern of cartilage formation indicates that their digits develop from positions that become digits II, III, & IV in other amniotes. Limusaurus has been argued to provide evidence that the digits of tetanurans, currently considered to be I, II and III, may actually be digits II, III, & IV, thus explaining the embryological position of bird wing digits. However, morphology and gene expression of the anterior bird wing digit specifically resemble digit I, not II, of other amniotes. We argue that digit I loss in Limusaurus is derived and thus irrelevant to understanding the development of the bird wing.
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- License:
- This document is licensed to the public under the Creative Commons Attribution 3.0 License
- How to cite this document:
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Vargas, Alexander, Wagner, Günter, and Gauthier, Jacques. Limusaurus and bird digit identity. Available from Nature Precedings <http://hdl.handle.net/10101/npre.2009.3828.1> (2009)
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