Re: Feathers Fly Worldwide.

[Dino Guy and Computer Gal <gbabcock@best.com>]

JAMES ARONIS wrote:

> Would it be presumptuous to assume that all theropods were feathered?

Yes.

> I
> am especially referring to the megafauna theropods such as Tyrannosaurs,
> etc. What about the other carnosaurs that belong to older families like the
> Allosaurs? These dinosaurs are not closely related to avian dinosaurs,
> correct?

Until recently, _Carnotaurus_ was the only non-avian theropod for which
definitive preserved integument was known (in the form of skin impressions).  It
had small polygonal tubercles arranged in rosette patterns around larger,
semi-conical tubercles.  (Tubercles are nonoverlapping scales, as in the flanks
of living crocodilians).  The _Carnotaurus_ skin impression fossils were
extensive, affording a good sense of the distribution and pattern of textures on
the living animal.  Unfortunately, little has been published on the integument,
although it was researched by Stephen Czerkas and incorporated into his
_Carnotaurus_ sculptures and his paper, "Skin," in Padian's and Currie's
_Encyclopedia of Dinosaurs_.  You can see the Czerkas' _Carnotaurus_ models in
_Dinosaurs: A Global View_, _Dinosaurs All Around_, Hunting Dinosaurs_, and
_Dinosaur Imagery_.

Tubercular tyrannosaur skin impressions have been reported, in a swatch about
the size of a playing card, but I haven't seen them figured or read any details.

The Liaoning discoveries have changed the look of many theropods.  Feathers or
protofeathers have now been described on a compsognathid (_Sinosauropteryx_), a
couple of species of oviraptorosaur (_Caudipteryx_), a therizinosaur
(_Beipiaosaurus_), and some dromaeosaurs (_Sinornithosaurus_, _Microraptor_,
plus the new specimen), not to mention _Protarchaeopteryx_, whose affinities are
unclear (as far as I know).  The largest of these was _Beipiaosaurus_, the
therizinosaur, which has been estimated at 2 to 3 meters in length.  Given the
short tail, the 2 meter figure may be more accurate, but you should bear in mind
that these guys were very stout as theropods go, so they were probably more
massive than you would expect a theropod of that length to be.

-- Ralph W. Miller III   ralph.miller@alumni.usc.edu