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Re: Why non-avian dinosaurs weren't able to survive

----- Original Message -----

From: Dann Pigdon <dannj@alphalink.com.au>
To: dinosaur@usc.edu
Sent: Tuesday, November 24, 2015 12:04 AM
Subject: Re: Why non-avian dinosaurs weren't able to survive

That's precisely what I suggested; each genus, family or superfamily likely had 
it's own fatal set of 
circumstances that were different to those of other genera, families or 
superfamilies. A large 
sauropod living close to the bolide impact site would have faced different 
stresses than a small 
theropod on the other side of the world. 

There's no single blanket hypothesis that can completely account for all 
extinctions at the end of 
the Cretaceous - probably not ever for all of the dinosauria specifically. 
Therefore the answer to 
the original question posed in this thread is; "there's no single answer". 
Non-avian dinosaurs were 
simply too diverse and widespread to have all be done in by a single defining 
event. Each species, 
genus, family, etc likely had a different tale of woe to tell.


Another reason why this is largely a misleading question to ask is that 
dinosaurs were not the only group of animals to not pass through the K/Pg 
event. If one is going to ask why the dinosaurs didn't survive they need to 
also ask why the mosasaurs, pterosaurs, plesiosaurs, ammonites, belemnites and 
the rest of the 75% of life on Earth didn't survive. That includes members of 
groups that only partially passed through the K/Pg event (e.g., what allowed 
neornithean birds to survive the K/Pg, but not enantiornitheans? Why did 
scincomorphan lizards pass through, but polyglyphanodonts did not?, etc.). 

The K/Pg event was so much larger than just the end of the dinosaurs.