RE: Feathers for T-rex?

["Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>]

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Michael Lovejoy
>
>  A couple of days ago, Doc Holtz wrote: "Since tyrannosaurs lie below the
> node for which Stage 3 feathers are synapomorphic, it is as
> likely they had
> only Stage 2 feathers (tufts of unbranched barbs attached to a calamus)."
> Where does Eotyrannus fit in to this? Does anything about it's
> phylogenetic
> position preclude the possibility of Stage 3 feathers?

All tyrannosauroids fall in precisely the same phylogenetic position with
regards to this: they are within the clade (Compsognathidae + birds)
characterized by Stage 2 feathers, but lie outside the clade
(Oviraptorosauria + birds) at which we can confidently place Stage 3
feathers.

So Stage 3 ARE possible for Eotyrannus, but at the same time are equally
possible for Tyrannosaurus.  And to the same degree that Stage 2 fluff is
possible for Spinosaurus.

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796