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Re: Oviraptorosaur tail forms and functions



Ronald Orenstein <ron.orenstein@rogers.com> wrote:

> I sent a query to the list that may have been lost in truncation:  is it 
> possible that the tail did serve an "aerodynamic" function, or at least a 
> stabilizing function in running
> (perhaps to make balancing or banking adjustments during rapid twists and 
> turns), rather than for defense or display (though of course a colourful tail 
> fan could still have
> a display function)?


This probably doesn't answer your question, but there is a hypothesis
(Carrier et al., 2001) that reduced tail length reduced rotational
inertia in maniraptorans, and therefore improved their ability to make
sharp turns when running .  This effect would be enhanced if the tail
was not only short, but stouter closer to the base of the tail.  But
this hypothesis doesn't explain the development of terminal fusion of
the tail vertebrae (such as forming a pygostyle), nor the presence of
large feathers on the tail (including a tail "fan").


Other hypotheses have proposed that large distal tail feathers could
help with aerial ground-to-air leaps (Caple et al.,1983), or leaps
from elevated surfaces to the ground (Garner et al., 1999).  The
former emphasizes the role of lift, the latter drag, in these
incipient flight behaviors.  But both models emphasize the role of the
feathered forelimbs and tail in controlling body orientation while in
the air, because in both cases the purpose of these leaps is prey
capture (flying insects or terrestrial prey, respectively).






Cheers

Tim





Cheers

Tim