RE: The new Archaeopteryx from... Wyoming?

["Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>]

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Tim Williams
>
> It looks like both Greg Paul and Kevin Middleton have some compelling
> support for their respective interpretations of the _Archaeopteryx_ foot:
> the second toe has a hyperextensible ungual, and the hallux is not
> opposable.  I'd have bet my life savings on the latter; but I never found
> GSP's interpretation of the second toe convincing - until now.
>
One thing of note, however: while the unit comprised of the ungual and pedal 
phalanx II-2 seem to have been hyperextensible, the
joint between pedal phalanx II-1 (the proximalmost phalanx) and metatarsal II 
are not. Indeed, it has a typical theropod shape for
II-1, not the  highly transformed one that is looking to be a good synapomorphy 
of Deinonychosauria (now that _Rahonavis_ is over
there...). The authors admit that the hyperextensibility in Archie is less 
developed than in deinonychosaurs (and _Rahonavis_).

> Anyway, here's the Abstract:
>
> Gerald Mayr, Burkhard Pohl, and Stefan Peters (2005).  A Well-Preserved
> _Archaeopteryx_ Specimen with Theropod Features.  Science 310: 1483-1486.

[snip]

The skull is beautiful, by the way, and preserves the dorsal view better than 
previous specimens.

> The phylogenetic tree has an _Archaeoptery_+_Rahonavis_ clade as sister
> taxon to a clade comprising deinonychosaurs and _Confuciusornis_ (with
> dromaeosaurs closer to _Confuciusornis_ than troodontoids).  In fact,
> _Microraptor_ and _Confuciusornis_ are recovered as sister taxa!  As
> mentioned in Jeff's New Scientist article (and no doubt Mickey M. would
> agree) the analysis probably needs to be fleshed out with more birds.  The
> article actually concedes this: "Although this particular result may be due
> to the limited sampling of avian taxa...".
>
This is the Huaxiagnathus paper matrix, with a few additions to the matrix. 
Agree that they need more birds.

In various interviews Makovicky & I (and others as well, I'm sure) lamented the 
fact that this was submitted just slightly too early
to include the Buitreraptor information, which would certainly mix stuff up 
more!

                Thomas R. Holtz, Jr.
        Senior Lecturer, Vertebrate Paleontology
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
        Mailing Address:
                Building 237, Room 1117
                College Park, MD  20742

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