RE: The new Archaeopteryx from... Wyoming?

[Guy Leahy <xrciseguy@sbcglobal.net>]

Wow... a very cool specimen indeed:

http://www.sciencemag.org/cgi/content/full/sci;310/5753/1483

I find it interesting that Archeopteryx and Rahonavis
fall out in the cladogram as closer to troodontids
than dromaeosaurs.  Perhaps powered flight was
acquired (and lost) multiple times within Paraves.

I had the opportunity a few weeks ago to view the
mounted Buitreraptor skeleton at the Field Museum.  I
was struck by how gracile the skeleton was.  It looked
more like a long-armed troodontid in general form than
most dromaeosaurs... :-)

Guy Leahy

--- "Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>
wrote:

> > 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
> 
> http://www.geol.umd.edu/~tholtz/
> http://www.geol.umd.edu/~jmerck/eltsite
> Phone:        301-405-4084    Email:  tholtz@geol.umd.edu
> Fax (Geol):  301-314-9661     Fax (CPS-ELT):
> 301-405-0796
> 
>