RE: FEATHERS FOR T-REX?

["Williams, Tim" <TiJaWi@agron.iastate.edu>]

Ken Kinman wrote:

>As for Plesion Alvarezsaurus, it 
>too seems to be in this same early maniraptoriform part of the tree (and
>probably therizinosaurs as well, although many people seem to have 
>difficulty accepting that possibility).

I think "many people" have difficulty accepting the way in which this
proposition was advanced.  It was done so by ignoring or overriding studies
that link _Alvarezsaurus_ to mononokines on the basis of a long list of
derived characters .  No data was offered by you in support of your
alternative phylogeny; it's all based on a "hunch".   

I, for one, accept the possibility that Alvarezsauridae is polyphyletic.  I
also I accept the possibility that tyrannosaurids could be secondarily
flightless birds (avialans).  However, at the current time, the available
evidence does not point in that direction.

>And it will help cushion the 
>shock if Mickey's analysis demonstrates the non-holophyly of 
>"Alvarezsauria".

As Mickey himself has often said (more times than he would probably care to
remember), there is abundant scientific literature already available to
support a monophyletic Alvarezsauridae.  There is no reason why you should
hold out in the hope that somebody, somewhere, will come up with a phylogeny
that corroborates your personal opinions.


Tom Holtz wrote:

>While in general I would agree with this, but I do want to remind people 
>that giant ground sloths included bear-to-elephant sized animals that
>lived in a wide variety of environments, including the tropics, and as >far
as we know they were all very hairy.  

Ditto for the marsupial megafauna of Australia.

 


Tim 

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

Timothy J. Williams 

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

Phone: 515 294 9233 
Fax:   515 294 3163