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Re: cervical ribs



>
>I've noticed that a lot of theropod dinosaurs have ribs emanating from
>their neck bones and I was wondering if anyone's given any thought as
>to their possible adaptive significance.  Or actually, since it seems
>like a great idea to have bones protecting the tubes running through
>your neck, perhaps someone could suggest a rationale as to why these
>bones have become greatly reduced or absent in the crown (living)
>groups of terrestrial vertebrates.  On the one hand I might think that
>these ribs would be lost in order to increase the mobility of the
>neck, but given that the cervical ribs are relatively prominent in _T.
>rex_ that would seem not to be the whole story.  _T. rex_ is thought
>by some (e.g. Gregory Paul) to have killed by darting its head forward
>to rip out a chunk of flesh and leaving a terminal injury in its
>intended prey.  The described behavior couldn't occur without suitable
>cervical felxibility.
>
>Is it possible that instead of just protecting the plumbing in the
>neck, the cervical ribs supported some structure that was lost or
>never appeared in other lineages?
>
>Anybody have any ideas?

It seems like most of the theropods had massive necks.  Also, they must
have been able to pass large chunks down their gullets.  I wonder if
they had muscles in their throat to help swallow.  Would the ribs 
provide a supporting framework?

Art