Re: semilunate carpal

["Tim Williams" <twilliams_alpha@hotmail.com>]

Dinogeorge wrote:

> So if the fossil record supports the ground-up/BADD version, then it's OK 
> to
> use it, no problem, but when it supports BCF, then we have to watch out for
> the gaps and so forth. Classic instance of hypothesis guidng the facts. 
> Bah.

Hmmm.  What I was driving at was an actual *analysis* of the fossil record.  
I have an inkling you might be confusing "ancestor" with "sister taxon".

Your argument boils down to "Well _Archaeopteryx_ comes before the 
dromaeosaurids in the fossil record; therefore birds evolved before 
dromaeosaurids."  This is a "face-value" interpretation of the fossil 
record.

However, an analysis of the distribution of anatomical characters (including 
those held to be "bird-like") among fossil taxa indicates that birds and 
dromaeosaurids share a common ancestry to the exclusion of other theropod 
taxa (except perhaps troodontids).

By the way, why are you so hooked on equating a maniraptoran ancestry of 
birds with a "ground-up" origin of avian flight?  A "trees-down" origin of 
flight can be very easily accommodated by a maniraptoran ancestry for birds. 
 Sankar Chatterjee thinks so, and he might be on target.


> Let's see a nice maniraptoran skeleton from the Middle Jurassic. I'll
> bet you it will be small and birdlike, like Archaeopteryx, if and when it 
> is
> found, not big, like Velociraptor.

How about if this Middle Jurassic skeleton was (a) small, (b) birdlike` and 
(c) like _Velociraptor_?  Because if this skeleton did fulfill these three 
conditions it *would* be very much like _Archaeopteryx_.


Tim


---------------------------------------------------------------------

Timothy J. Williams

USDA-ARS Researcher
Agronomy Hall
Iowa State University
Ames IA 50014

Phone: 515 294 9233
Fax:   515 294 3163



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