RE: FEATHERS FOR T-REX?

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

T. Mike Keesey wrote:

> >To put it another way, possession of feathery integumentary
> >structures is *minimally* primitive for the Maniraptoriformes (if
> >_Sinosauropteryx_ is a basal maniraptoriform).
>
>Kind of a big assumption, isn't it? I would say it's minimally primitive
>for Clade(_Sinosauropteryx prima_ + _Vultur gryphus_). 

This is kind of what I meant.  I used the name "Maniraptoriformes" for this
clade; I know it isn't the definition, but it approximates the content.  In
which case, it isn't a big assumption - although, perhaps a minor
assumption, since it assumes that _Sinosauropteryx prima_ is a basal
maniraptoriform.  

In any case, I think we may be splitting hairs (or protofeathers) here.  The
alvarezsaurids may lie closer to the base of the Maniraptoriformes than
_Sinosauropteryx_, in which case _Shuvuuia_ is the most basal theropod to
show feather-like integumentary structures.  In this case, the possession of
feather-like integument is minimally primitive
for Clade (_Shuvuuia deserti_ + _Vultur gryphus_).  According to Xu et al.
(2002), Tyrannosauridae lies outside this clade.  Close, but no cigar.  

(By the way, I've seen "Shuvuuia mongoliensis" written in the Ostrom
Symposium volume; I'm assuming it's a misspelling of _Shuvuuia deserti_).

>Whether certain
>clades (_Tyrannosauroidea_, _Ornithomimosauria_, etc.) belong to that
>clade or not is currently unresolved.

Depends which paper you consult, I guess.  I used the phylogeny in the
_Sinovenator_ paper.  


Tim

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

Timothy J. Williams 

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

Phone: 515 294 9233 
Fax:   515 294 3163