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Re: Dinosaurs are not mammals



[Alright, simmer down you two or we'll have to take you outside and
 hose you off! :-) -- MR ]

Rob Meyerson wrote:

> Hogwash!  If what you say is true, how does one explain the
> chasmosaurines tendancy for large fenestra in their frills?  How
> else does one explain the holes in the skull which lead from the
> lower jaw to the fenestra?  The only plausible explanation is that
> the frills are attachment sites for the jaw muscles.  Since this is
> the case, is it not reasonable to suggest that those with longer
> frills had stronger chewing power than those with shorter frills?
> The frills were most certainly related to muscle attachment.

Hogwash! Have you seen any real or cast's of Ceratopian skulls? I've 
seen dozen's of them. I've talked to paleontologist who specilize on 
Ceratopians. The fenestra have NOTHING to do with jaw muscles. If the 
frill had anything to do with the jaw muscles they would have broken 
there frills because they are so lightly built. There ARE two holes 
behind the eyes (I forget the real name for them) that the muscles did 
attach to the first few inches (ONLY) of the back of the skull, NOT the 
total frill. 

Did you know that the top of the braincase isn't the top of the skull? 
That there is a large sinus between what would normally be the top of 
the skull and the actually top of the skull in ceratopians. Some 
ceratopian's have a hole or in life would be a soft spot. Or that the 
brain of Triaceratops is actually just a little below the orbit's.

The fenestra theroy for jaw muscle attachment is old and totally wrong.

> Sure, dinosaurs are not mammals.  However, we can do comparisons
> between forms, to see if there are any similarities.  Convergent
> evolution happens all the time, and to toss this aside just because
> the animals in question are not closely related seems a little
> short-sighted.  To say that the Ichthyosaur (not a dinosaur, I know)
> is not convergent with the dolphin just because the former is not a
> mammal would result in our losing a great deal of insight into the
> lifestyle of the Ichthyosaur.

Well, whale's swim with an up and down motion of he tail, Ichthyosaurs 
swim with side to side. Ichthyosaur orbit's are large, nose small, 
vertebrae are more like sharks in makeup than dolphins. Ichthyosaurs 
are not like dolphin's and shouldn't even be drawn with them leaping 
out of the water! (though it is a interesting drawing).

Yes, there is convergent evolution, but we must use the correct 
convergent animals.

Tracy