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Re: snap-action predation



I wrote:

<<They are adaptive to display, or to affect torsional stabilization. I
suggest the same may be true of dromaeosaurids and other still-tailed and
short-tailed theropods, which likely precludes, as Mike Skrepnik
illustrated, a tail fan for *Nominga* as a result of the pygostyle.>>

Michael Skrepnick (palaeopaint@dinosaursinart.com) wrote:

<Explain this concept to a peacock, whose visual array doesn't seem to be
predicated on increased physical performance or lack thereof. In
"grounded" dromaeosaurids / pygostylians utilizing their tails as dynamic
stabilizers to whatever degree ( or not), or in other less advanced
terrestrial theropods (with a more conventional caudal series ) sporting a
tailfan array, perhaps locomotory considerations (or impact on same) make
little difference.>

  I provided that long display feathers are an adaptive trend that may
have been the incipient preclusion for a tail fan, as streamer tails
adversely affect flight performance.

  As for *Nomingia*, I was only drawing an exaptive parallel, said nothing
of the presumption or inclusion of a tail fan in that taxon, but that it
seems to fit the prediction.

  Cheers,

  When Nomingia was being described, it was of some
> importance to
> Phil Currie to include a tail fan in the reconstruction.  Of course,
> there
> is no physical evidence indicated in the specimen to substantiate the
> existence of a caudal array, as there is nothing forward of the ilia on
> which to base an image of the front half.  My experiences with Phil have
> shown time and time again that he puts a great deal of consideration
> into
> formulating opinions on specimens before putting them to press and
> always
> expresses from a conservative viewpoint in his analysis.  You can ask
> him as
> to his reasoning on how the anatomical features in the Nomingia image
> were
> developed, however, I can tell you that the tail fan didn't simply
> appear in
> the artwork because I didn't have anything better to paint that day 
> ;o).
> 
> Mike Skrepnick
> 
> 


=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

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