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RE: ORNITHISCHIANS :-)




-----Original Message-----
From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of Ken
Kinman
Sent: Wednesday, June 13, 2001 9:20 PM
To: dinosaur@usc.edu
Subject: Fwd: RE: ORNITHISCHIANS :-)


Dear All,
     Tracy asked me to forward the post (down below) to the whole list.
     I was a little surprised at first, but I guess it is a question that
should be considered.  I'm not sure why stegosaurs in particular might be
classified outside of an ornithischian clade, but if they were, I think
ankylosaurs would probably have to be classified separately as well.
     I'm not sure, but are you suggesting that the predentary might have
evolved independently in two or more lines (stemming from different groups
of primitive dinosauromorphs?   I've never really considered that
possibility----I guess it is possible, but doesn't seem very parsimonious.
But then again, before last weekend I knew very little about ornithischian
phylogeny, so I am a relative "newbie" on this subject.  Will have to roll
the idea of a "polphyletic ornithischia" around in my head.   But if it is
polyphyletic, that is kind of scarey.  If the interrelationships of just
three major groups of dinosaurs is problematic, think how messy it would get
if we had even more independent groups to consider.

Here, let me try and send this to the list this time :>
We, as humans, like to classify things (I know I do!!!) and we have a pre or
nearly pre-determined or set agenda to do so, or to make new ones (as in the
Linnean, cladistic or Phyla-code) (Hi, my name is Tracy L. Ford and I am a
Linneanist). But none can ever be correctly tested. They can be tested by
theories, math (cladistics), or point of view, but who is to say which one
is correct? How many new cladgrams must we endure? Who is to say what is to
be coded and which isn't. Is the more numbers better than less? The same
questions can be used for the other methods.

May be stegosaurus and ankylosaurs developed a predentary differently from
the known ornithischians. I believe that Prosauropods and Sauropods were
sistergroups (I hope I'm using that term right) and not related to one
another (I've some inside knowledge on work being done, and have believed
this for some time). Perhaps flight has been developed different times.
Maybe it is the enanithornithid line that gave rise to the flying dinosaurs
and not the 'modern' bird line (or maybe they both did). This would mean and
I've said this before (it should be somewhere in the archives) that if
dromaeosaurids are closely related to Archaeopteryx, and if as Larry Martin
and others believe is an enanithorinithid, then dromaeosaurids are
enanithornithids. But where do you draw the line. Some of it is bias, some
of it is what one believes and will keep fighting against it (look at
Feduccia and his ilk). In many ways, paleontology is philosophy.
What I want to stress is we, both paleontologist and lay people, keep an
open mind to new ideas and new finds. In the near future, some new animals
will challenge this (from what I know and I'm sure many of which I am
totally unaware of).

Tracy