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Re: late night thoughts: adults only
You are right in a sense, although I don't feel there is any functional
difference between Asian and American tyrannosaurs/sauropods. I accept that by
using the term "T. rex", I inadvertently restricted aspects of my comments to
N. America. Still, I had thought that the overlap between T. rex and sauropods
in N. America was minimal and early, not zero. Not that my assessment of the
physical vulnerability of sauropods is affected, or my perception of the
stealth-through-immobility options/capabilities of T.rex and functional
equivalents (notably including allosaurids).
Nor was I aware that the difference in last appearance times of sauropods in
Asia/North America was so dramatic and clearcut. It seems likely
preservation/collection bias scenarios can be eliminated as explanations. If
that is correct, is there a 'mainstream' explanation?
----- Original Message ----
From: David Marjanovic <firstname.lastname@example.org>
To: DML <email@example.com>
Sent: Friday, June 8, 2007 7:32:56 AM
Subject: Re: late night thoughts: adults only
> I understand that consensus is that when T. rex proper was in full flower
> sauropods were getting kind of scarce... might have been one prey/predator
> race where the predator won. Maybe Horner is right in that they were down
> and out at the end; but only if they had run out of the good stuff, in my
> opinion. }:D.
- North America seems to have lost all of its sauropods at the end of the
Cenomanian (though the bad fossil record between the Cenomanian and the
Campanian may be fooling us). That's _thirty million years_ before the first
*Tyrannosaurus*. In the Campanian, "*Alamosaurus*" turns up (though it
apparently stays in the southern part of the continent), and _then_ we get
- Asia seems to have had sauropods all the way to the end of the Cretaceous;
the appearance of *Tyrannosaurus* does not seem to have made a difference.