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Re: Today Cordillera, tomorrow the world.



In a message dated 5/18/01 11:53:05 PM Eastern Daylight Time, 
rob_redwing@hotmail.com writes:

>        Ceratopsids were always unknown in the east<
>  As mentioned onlist earlier today, absence of evidence is not always 
>  evidence of absence. With hadrosaurs in the Eastern US, and the Western US 
>  (all the way to California!), I don't see what would prevent ceratopsids 
>  migrating across the


Right on! However, I'd like to add that we _DO_ have evidence for 
ceratopsians from the Aptian of Maryland in the form of 3 single rooted, 
Neoceratopsian teeth from my site (see ref below) as well as yet to be 
documented tracks discovered by Ray Stanford. If these hold up as 
ceratopsian, this makes them the oldest remains of such in North America. Now 
one of my co-authors does not agree with what I am about to say, by I believe 
this forces one to reconsider the timing and direction of ceratopsian 
migration from a late-K Asian - Berringia route to an earliest K 
Eurasian-Canadian Maritime route. Alternately, it could be one of a number of 
separate vicariant events. Not enough data to say...

      Refs.                   
Chinnery, B. J., Lipka, T. R., Kirkland, J. I., Parrish, J. M., and 
Brett-Surman, M. K., 1998, Neoceratopsian teeth from the Lower to Middle 
Cretaceous of North America, in Lucas, S. G., Kirkland, J. I., and Estep, J. 
W., (eds.), Lower and Middle Cretaceous terrestrial ecosystems, New Mexico 
Museum of Natural History Bulletin 14, p.297-302.


Lipka, T. R., 1998, The affinities of the enigmatic theropods of the Arundel 
Clay facies (Aptian), Potomac Formation, Atlantic Coastal Plain of Maryland 
in Lucas, S. G., Kirkland, J. I., and Estep, J. (eds.), Lower and Middle 
Cretaceous terrestrial ecosystems, New Mexico Museum of Natural History 
Bulletin 14, p.229-234    

Can be found on line in their entirety at:
http://www.wam.umd.edu/~lfsxdth/dino/paper/index.html

Cheers,

Tom
Thomas R. Lipka
Paleontological/Geological Studies
Tompaleo@aol.com