Re: Jurassic Park

["T. Mike Keesey" <tkeese1@gl.umbc.edu>]

On Fri, 25 Sep 1998, Larry Dunn wrote:

> ---Scott A Hartman <ottscay@uwyo.edu> wrote:
> >
> > Randy,
> >      Although it wasn't as commonly accepted at the time Jurassic Park
> > came out, Velociraptor almost certainly had a feather-like or fur-like
> > insulatory covering.
> 
> What makes you say that, Scott? 

It's *real* simple: _Sinosauropteryx_, a compsognathid, had hair-like
"proto-feathers". Birds have feathers. In pretty much every phylogeny
published recently, dromaeosaurids share more recent ancestry with birds
than with compsognathids.

Hence:

|--_Sinosauropteryx_ ("proto-feathers")
+--+--_Velociraptor_ (skin impressions unknown)
   +--Aves (feathers)

It is parsimonious to assume that "proto-feathers" and feathers are
homologous. Therefore, _Velociraptor_ either had integument or secondarily
lost it. I can think of no reason why a small, non-burrowing, non-aquatic,
non-wallowing animal like _Velociraptor_ would lose integument. 

Of course it's not proven, since we don't have dromaeosaurid skin
impressions, but that's why Scott said "*almost* certainly".

It is for similar reasons that we assume animals like _Ichthyornis_ were
feathered.

--T. Mike Keesey                                   <tkeese1@gl.umbc.edu>
DINOSAUR WEB PAGES -- http://www.gl.umbc.edu/~tkeese1/dinosaur/index.htm