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Re: Feduccia ORIGIN



George O. wrote:

>Retroverted hallux (articulating in a shallow groove on the second
>metatarsal, distally on the palmar side) occurs in all theropods, and only in
>theropods, at and above the common ancestor of ceratosaurians and tetanurans.
>In almost all the larger cursorial forms, however, the retroverted hallux is
>secondarily reduced and points, in varying degrees, posteromedially.

        Last time I had checked, dromaeosaurs were the only animals in which
this was confirmed (I believe this was per the juvenile _Saurornithoides_
article in the Joint Sino-Canadian Dinosaur Expedition issue of the Canadian
Journal of Earth Sciences).  There are tracks which show a retroverted
hallux (Paul 1988), but no anatomically confirmed instances beyond the
Avialae+Dromaeosauridae clade.  I was under the impression that there was
some room for interpretation in many theropods, as these elements were
either disarticulated or their articulations were distorted post burial.
Could someone else confirm or deny George's statements?  This is a rather
important point.

        Wagner


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| Jonathan R. Wagner                    "You can clade if you want to,     |
| Department of Geosciences              You can leave your friends behind |
| Texas Tech University                  Because your friends don't clade  |
| Lubbock, TX 79409                               and if they don't clade, |
|       *** wagner@ttu.edu ***           Then they're no friends of mine." |
|           Web Page:  http://faraday.clas.virginia.edu/~jrw6f             |
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