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Re: Response II



In a message dated 6/3/01 0:42:31 AM EST, KELL00BELL@aol.com writes:

<<  Anchiceratops didn't migrate to Mongolia with Saurolophus. >>

Don't be so sure that the Mongolian Saurolophus and the American Saurolophus 
belong in the same genus. They look mighty alike, but there are also a few 
differences that suggest that the two species may have arisen convergently 
but independently within Saurolophinae from a common Prosaurolophus-like 
ancestral form.

I have yet to find a way for any kind of faunal interchange to take place 
between North America and Asia across the Bering land bridge between Late 
Santonian and Late Maastrichtian. The land bridge must have been under about 
100 meters of water during that time. Even today, when the sea level is 
considerably lower, the land bridge remains closed. It took an ice age to get 
rid of the water there.

Before Late Santonian is a different matter entirely. There was extensive 
faunal transfer between the two continents, which is why the same families 
appear in both.