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Re: New dinosaur diversity articles



> Date: Sat, 02 Oct 2004 10:29:29 -0700 (PDT)
> From: Tim Donovan <uwrk2@yahoo.com>
> 
> > The data do not suggest that dinosaurs were decreasing in richness
> > leading to extinction during the last 10 m.y. of the Cretaceous.
> 
>   Lambeosaurs appear far less diverse in North America by the early
> Maastrichtian. Hypacrosaurus is the only post Campanian NA
> lambeosaur genus known AFAIK.  Centrosaurines were also down to one
> genus by then-Pachyrhinosaurus-and were totally gone by the late
> Maastrichtian. Saurolophines had also vanished by then. The recent
> Ankylosaurus paper claimed that ankylosaurs disappeared before the
> end. That may not have been true of Ankylosaurus, since specimens
> are stratigraphically high, and one occurs right below the K-T
> according to Wroblewski's data. Edmontonia, however, may have
> disappeared before the end.

Isn't this just a matter of lambeosaurines being superseded by
hadrosaurines, centrosaurines by chasmosaurines, and nodosaurids by
ankylosaurids?

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