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Fw: Re: Triassic dinosaur evolution



Except for balance, as someone (I think Graydon) pointed out
in a previous thread. 
 
As a tall biped, seizing an animal that weighs as much as
you is a good recipe for getting pulled off your feet, and
having some hooked levers to push off/hold on the flank of
the 'grippee' would be very handy for the
'gripper'. Could also increase wounding power,
especially in pullback/worry phase, and help to maintain
position/balance for another bite (or even flight).

Probably, as prey gets larger, then the arms can be
relatively shorter, assuming the attacker is approximately
equal in height to prey.
 
Don
> 
> --- On Wed, 9/17/08, Michael Habib <mhabib5@jhmi.edu>
> wrote:
> 
> > From: Michael Habib <mhabib5@jhmi.edu>
> > Subject: Re: Triassic dinosaur evolution
> > To: pristichampsus@yahoo.com
> > Cc: dinosaur@usc.edu
> > Date: Wednesday, September 17, 2008, 9:53 AM
> > > Then could someone please pass this on to all the
> paleo
> > artists out 
> > > there? I've grown so tired of seeing drawings
> of
> > theropods with 
> > > completely serviceable forelimbs, just tucking
> them
> > away like they 
> > > were just featherless, non-functional wings.
> > 
> > Fair enough, but what counts as
> "serviceable"? 
> > If you're thinking of 
> > maniraptorans, then I absolutely agree.  However,
> there is
> > a strange 
> > pattern that many (if not most) non-maniraptoran
> theropods
> > with robust 
> > forelimbs still can't reach out in front of their
> > mouths, making the 
> > forelimbs rather unavailable in prey capture. 
> Allosaurids,
> > for 
> > example, have robust, powerful arms - but the length
> is
> > still quite 
> > short in comparison to the total length of the
> cervical
> > series and 
> > head, so the jaws would contact food well before the
> arms
> > ever got 
> > close.  That doesn't make the forelimbs useless,
> but it
> > appears to make 
> > them rather unimportant for prey acquisition.
> > 
> > Cheers,
> > 
> > --Mike H.
> > 
> > 
> > Michael Habib, M.S.
> > PhD. Candidate
> > Center for Functional Anatomy and Evolution
> > Johns Hopkins School of Medicine
> > 1830 E. Monument Street
> > Baltimore, MD 21205
> > (443) 280 0181
> > habib@jhmi.edu