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Re: The Final Days



--- Kashman7@aol.com wrote:
> I keep hearing over and over that the dinosaur's huge food requirements were 
> paramount in letting them fall at the K-T while birds, reptiles and 
> amphibeans survived.
> Yet, large crocodilians seem to have made passage over the gap. Or were they 
> all decended from smaller survivors.
> 
> Has anyone done a study of what dinosaur species closest approached the 
> boundary that were small? Say, less than 3 meters in length? Even duck-sized 
> dinosaurs, if any at that time. Heck, ducks made it accross.

People often say that non-avian dinosaurs went extinct at the K/T noubdary,
which is true, but it's more accurate to say that non-neornithean ornithodirans
went extinct (unless _Ornithodira_ is an unnatural group ... then
non-neornithean dinosaurs would be more accurate). There were plenty of
non-neornithean avians in the Maastrichtian (enantiornitheans,
hesperornithiforms, ichthyornithiforms) which seem to have perished alongside
most of the other dinosaurs. Many of these were under duck size.

(Of course, some use _Aves_ as a crown group, in which case "non-avian
dinosaurs" would be accurate -- kinda confusing....)

=====
=====> T. Michael Keesey <keesey@bigfoot.com>
=====> The Dinosauricon <http://dinosauricon.com>
=====> BloodySteak <http://bloodysteak.com>
=====> Instant Messenger <Ric Blayze>
=====

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