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Re: again: frill of Triceratops
> process of reinforcement. Initially it evolved due to sexual selection.
> Subsequently it gave a an oppurtunity for jaw muscle attachment and again
> it was reinforced by sexual selection.
Enlarging parietals would be providing larger muscle attachment areas
before they started looking especially big and sexy.
> times in evolution like the Austropithecus. robustus cranial crest. I
The R.robustus cranial crest would not even have been visible with
the temporal chewing muscles in place, any more than you can make out the
sagittal crest on a gorilla's skull in a fleshed out animal.
I think it is time for someone especially knowledgeable on the
subject to give the complete run down on respiratory turbinals. I know
this subject pops up on this list a lot, but some of the comments that
have been made about the SCIENCE paper seem to show misunderstanding of the
purpose RTs serve in endotherms.
I might also add that as far as I know, the vast majority of
vertebrate tetrapods habitually breathe through thier noses except
during those relatively rare times when they have been doing serious
exerting. Begging off small nasal passages in dinosaurs by saying they
all might have walked around breathing through thier mouths seems like a
pretty poor dodge. Sort of like saying pterosaurs could have been fully
terrestrial if they walked around all the time with thier wings folded