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More nose thoughts



Tracy Ford wrote:

>Why in the world would an animal evolve with it?s nose on top of its head
if its nostrils
>were still at the front?

Actually, most living examples of amniotes with external nares on top of
their heads that I can think of actually have their fleshy nostrils in
front, and sometimes WAY in front.  The most obvious ones are elephants and
tapirs.  In extinct forms, add (it is presumed) Macrauchenia.  The external
nares of horses slit WAY back onto the face, yet the nostrils are only at
the front end.

Among reptiles with nostrils on the tops of their heads... well... Hmmm...
Can't think of living reptiles showing this condition.  Parasuchians, sure,
and in this group there is no evidence in terms of the blood vessel foramina
to support nostrils in any place OTHER than the external nares.

Witmer's paper seems to be written to address the what (i.e., "what was the
position of the fleshy nostril in various Mesozoic dinosaurs?").  He
discusses a couple of possible "whys", but since the study of the fleshy
nose is just beginning, there is still a lot of work to be done.

                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