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Re: Daspletosaurus: Part 2



In a message dated 98-02-04 01:49:12 EST, se1aard@itis.com writes:

<< Crossed to Asia, gave rise to T.
 bataar, which crossed to U.S. and became T. Rex? >>

The extreme unlikelihood of this scenario is what made me decide that the
Asian tyrannosaurids--like protoceratopids and certain other dino
groups--underwent their own evolution independently of the North American
forms. With the sea level 100+ meters higher than it is today, and major
epicontinental flooding throughout the Campanian and Maastrichtian, there is
no way any Asian forms could have gotten over to western North America across
the Bering region or any other way during those epochs. The Asian
tyrannosaurids are genera distinct from the North American forms, and their
similarities are all explicable as convergences and plesiomorphies.

Whether or not the Asian tyrannosaurids are distinct genera from one another,
however, is still moot.