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Re: Triceratops sprawl

On Fri, 2 Feb 1996, Rob Meyerson wrote:
> These are reasonable objections.  However, I point out that the big=
>  ceratopians first appear in North America.  According to my theory,=
>  protoceratopids evolve in the sands of the Gobi with the features I have=
>  mentioned that make them a very successful animal.  When they migrate to=
>  North America, the "dune buggy" design, which gives them an immense=
>  stability (definately an advantage) on the "stable" land surface, which=
>  helps them to be an extremely successful group.  This success is marked by=
>  an increase in size.
        There's no proof that protoceratopsids as a group evolved in
the deserts of Mongolia. All we know is that a couple branches of the 
marginocephalian family tree- Protoceratops and Psittacosaurus- show up 
there, which proves only that Protoceratops and Psittacosaurus lived in 
Mongolia. Their ancestors could have lived anywhere in asia, and probably 
did live all across asia, the only thing special about Mongolia is that it
has the right conditions for these animals to show up. Their ancestors 
could have evolved in any number of places besides dunes.
 If a future 
paleontologist found skeletons of a jackrabbit, a spadefoot toad, a 
tortoise and a coyote in desert sediments, could they then conclude that 
lagomorphs, anapsids, anurans and canids all evolved in desert 
conditions? Or if this future paleontologist found fossils of ground 
sloths in florida, and mammoths in south america, could they justifiably 
conclude that these were the ancestral homelands of the group?
        Not to mention the fact that Cretaceous North America is not 
noted for sand dunes (I suppose Pachyrhinosaurus went dune-busting up on 
the North Slope?), the fact that putting the limbs out to the side is 
competely contradictory to the trackway evidence, and that animals like 
camels get along just fine with long, erect limbs.
        -Nick L.