Re: Follow-up: the truth about killer dinosaurs

["T. Michael Keesey" <keesey@gmail.com>]

On 8/31/05, Michael Mortimer <mickey_mortimer111@msn.com> wrote:
> 
> Though none of the tyrannosaurid skin impressions has been specified to a
> certain body area, are we to believe they were all pedal?

If they can't be assigned to a specific body area, are we even sure
they're tyrannosaurid? (I admit I don't know the details very well.)

And which part of the body makes the most impressions? (Okay, that's
for live animals; but again, what are the details of the tyrannosaurid
skin impressions?)
 
> I can't picture replacing feathers with scales, but what if the juveniles
> had scales with feathers in between (like opossum tails have scales and
> fur), then shed the feathers perminantly on the way to adulthood.  Of
> course, if I'm going to posit that, I wonder if impressions of interspersed
> feathers would be preserved at all in Judith River sediments (or Morrison or
> La Colonia for that matter).

Moreover, _Dilong_ doesn't show this, so it would have to be a derived
trait of tyrannosaurids. Simpler hypothesis: sparse feathers in adult
tyrannosaurids, along with areas of scutellae (including at least the
feet).

—Mike Keesey