Re: The new Archaeopteryx from... Wyoming?

[frank bliss <frank@blissnet.com>]

It has been a BAD kind of week on the DML.

I believe it is highly likely that that some theropods that evolved 
bird like characteristics, flew (or any other related activities)  a 
while, and then eventually settled back down to an earthly existence 
filling in what ever niches that didn't require flight. A wide spectrum 
of aeronautic activities were available to the adaptable and when those 
traits were not useful, out the door they went. The rush toward flight 
was not a one way street and (no doubt) there were many banked turns 
along the way.  The sinuous (obfuscating to us) nature of evolution 
that threw cetaceans back in the water after their ancestors originally 
spent so much evolutionary capital to crawl out was no doubt in action. 
 Dromaeosaurs et al may have just been the metaphorical ostrich 
equivalent of the day (with an attitude of course).  We will see that 
an anastomosing cladogram will be the eventual result when all the data 
is in.

Frank (Rooster) Bliss
MS Biostratigraphy
Weston, Wyoming

On Dec 2, 2005, at 6:52 AM, Thomas R. Holtz, Jr. wrote:

> > From: Guy Leahy [mailto: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.
>
> Actually, they found their Archie-Rahonavis clade as the sister taxon 
> to Deinonychosauria as a whole, but have Confuciusornis as the
> sister taxon to Microraptor within an otherwise-conventional 
> Dromaeosauridae.
>
> >  Perhaps powered flight was
> > acquired (and lost) multiple times within Paraves.
>
> Perhaps. Or (as I have argued before), perhaps actual powered flight 
> is limited to Pygostylia or even a more restricted clade
> (Ornithothoraces perhaps?), and small members of the other paravian 
> branches had limited aerodynamic ability (WAIR, gliding, etc.)
> rather than actual powered flight.
>
> > 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... :-)
>
> Quite so. In fact, as we get more basal specimens from each of 
> Pygostylia, Dromaeosauridae, Troodontidae, and Archaeopterygyidae,
> they are getting far tougher to tell apart...
>
>                 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/
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