RE: Gliders to Fliers? (Was Re: Ruben Strikes Back)

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

> -----Original Message-----
> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Larry Febo
>
>
> Which brings to mind the dilemma...if theropods were developing bipedality
> in order to run faster, why would they develope feathers on the arms, or
> larger arms for that matter. It seems this would tend to slow them down!
>
"Seems", yes, but do you have evidence it *would*?  That is, do you have
evidence that animals with a covering of feathers run slower than animals
with a covering of scales which otherwise are identical in size and shape
(and physiology)?

At least one ornithologist suggested (at the the SICB Feather Origins
symposium) that feathers developed for streamlining on the ground first, and
only later became useful for flight.

Additionally, there are other possible uses for feathers:
Insulation
Display
Brooding
To name a few.

Furthermore, the origin of Theropoda and the origin of feathers seem (with
current evidence) to be two separate events: theropods split off from other
dinosaurs first, and feathers can only be tied with confidence at present to
the base of Coelurosauria.  Furthermore, the majority of feathers outside of
Avialae are simply body coverings, not flight feathers (no surprise here to
any one but Martin and the Feducciaries, who have tended to equate "feathers
= flight = birds").



                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