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Re: Triceratops sprawl
>There is a rather sizable hole in your argument: big neoceratopians (the=
>ones that are supposed to sprawl) don't show up in dune sediments!
>The numerous land connections between Asia and western North America that=
>occurred near the end of the Cretaceous (Dinogeorge notwithstanding) mean=
>that they certainly *could* have spread back into Asia. After all,=20
>protoceratopids of Asian mold show up in latest Cretaceous North=20
>America. Apparently the big ceratopids *disliked* the dry dune=20
>conditions prevalent in east Asia.
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.
Their evolution continued here in North America. To illustrate this, If one=
takes a skeleton of _Protoceratops_, and compares it to _Triceratops_ (both=
drawn to appear that they were the same size), one sees that P-tops is=
built to be more sturdy, while T-tops is built more lightly. I suggest=
that the neoceratopians sacrificed some of their dune busting design, while=
keeping the advantageous portions (the basic forelimb design, for example).=
This simply meant that they "couldn't go home again."
>I also have trouble seeing how sprawling forelimbs make for a very=20
>effective "dune busting" mode of locomotion.
Take a look at a dune buggy sometime. The similarity in forms between the=
ceratopian forlimb system and a dune buggy front axle assembly are=
remarkably the same.
Q. What fossil fish is a blood relative?
A. The antiarch.