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RE: Gauthier & de Quieroz et al.



 
David Marjanovic wrote:

> >I have to agree with you here.  There is definitely a large number of
> >Mesozoic avian species emanating from the Soviet Union (past and
> >present) that are based on scrappy, indeterminate material.
>Why "and present"?

I meant from the area covered by the former Soviet Union and its satellites.


George Olshevsky wrote:

>By almost all, if not all. You might want to take a look at the
>politics of molecular phylogenies versus morphological phylogenies. 

Having a foot in both camps, I have to say that the "political" mudslinging
between proponents of molecular phylogenies versus morphological phylogenies
is vastly overrated (and over-hyped).  Sure, the debate can become very
heated, especially for mammals, with widely divergent trees put foward by
both "camps".  However, on some issues, such as the whale-artiodactyl thing
(which I admit is exceptional in the degree of congruence of molecular and
morphological phylogenies) a consensus is developing on the precise
topology.  For non-tetrapod vertebrates, there is a great deal of overlap
between molecular and morphological phylogenies, although points of
contention remain.  For example, the fossil and molecular evidence are at
odds with respect to the order in which various cartilaginous fishes
diverged, with the batoids (rays and skates) proving particularly
troublesome.  (I only became aware of this after talking to a fossil shark
expert from AMNH; I don't know enough about this topic to offer an opinion
on who's the more correct.)


Ken "Rudolph" Kinman wrote :
 
>I think Simon is skating on thin ice in this case, and I have told him 
>so.  The Crucible of Creation is a wonderful "must-have" book in my
>opinion.  However, I would take Simon's halkieriid-to-brachiopod
>hypothesis with a huge grain of salt. 

"The Crucible of Creation" is a marvellous book - I'd highly recommend
it.  I'm not sure why you regard the halkieriid-to-brachiopod hypothesis as
less likely than the other way round, for much the same reasons as David.  I
guess that Acme homoplasy-detector (a.k.a "red nose") of yours is lighting
up again.


Nick Pharris wrote:

>I don't have a problem with HP Kinman going looking for characters to
>support his phylogeny,

Nor do I - as long as one isn't lulled into casting a blind eye over
characters that *do not* support the phylogeny.  I think this is the crux of
the debate.  We all have "it-makes-me-feel-all-warm-and-gooey-inside" ideas
on how a particular group of organisms involved; but, in the cold light of
day, such scenarios aren't worth the paper (or bandwidth) they're written on
unless they're tested against the available data.  If you're prepared to
subordinate every other character to the presence or absence of one "key
apomorphy", you could (if you wish) propose that birds evolved from a ham
sandwich.


Tim





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

Timothy J. Williams 

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

Phone: 515 294 9233 
Fax:   515 294 3163