Paleo-mimics: predictions

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

With regards to the recent discussion of paleo-mimicry (in the sense that
Ken Kinman refers: that is, ecological mimicry rather than functional
convergence), a thought of some things to look for in cases of the evolution
of such an event:

Although the taxa in question may have earlier origins in disparate regions,
they must be in sympatry (same place, same time) before the evolution of the
mimicry.

While sympatric, one of the two taxa must have the morphology present at a
time when the other form does NOT have that morphology developed yet.

After some time, but still in sympatry, the second form would acquire the
morphology.

In the case of therizinosaurs and ornithomimosaurs, we sadly do not know
enough about their early evolution to judge in either case.  I think these
would have been bad mimics (at least in terms of body form), because they
really have VERY different body builds.  I could perhaps except an
alvarezsaur-ornithomimosaur mimicry, or even an ornithomimosaur-elaphrosaur
mimicry, given that these body plans are much closer in proportions.
However, again the evidence simply isn't there yet for this hypothesis.
Food for thought, though!

                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