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Re: Extinction Question and a Thank You!

Maybe it depends on what you call a crocodylian?

They actually evolved before the dinosaurs from their common ancestor.

Dora Smith
Austin, Texas
----- Original Message -----
From: "T. Michael Keesey" <keesey@gmail.com>
To: "Dinosaur Mailing List" <dinosaur@usc.edu>
Sent: Saturday, February 05, 2005 5:20 PM
Subject: Re: Extinction Question and a Thank You!

> On Sat, 05 Feb 2005 22:56:42 +0000, Dinosaur World <dinoworld@msn.com>
> >
> > What I am not clear on is why there are so many modern animals that have
> > retained the same basic design as their Permian and Cretaceous
> > If early Crocodiles, Alligators, Sharks, Insects etc. were subjected to
> > global environmental changes that were long enough and strong enough to
> > out other species, why then do they still resemble their modern
> > counterparts?
> This assumption is difficult to quantify, and hence hard to test. I
> wouldn't take it as a given. CMIIW, but I think the Cenozoic clades of
> crocodylians and sharks arose during the Cretaceous, but were not
> around during the Permian.
> -- Mike Keesey