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Re: Iguanodontidae and Theropod Boredom



Jaime,
    Well just one more post before I get to bed, and be forewarned I tend
to ramble this late at night.  I keep trying to get into Ornithischians, but
even the lure of a paraphyletic Thyreophora was shifted to the backburner
once the possible non-holophyletic status of Therizinosaurs distracted me
once again.  Also, I'm now finally getting interested in the debate over
whether snakes evolved from terrestrial lizards or marine mosasaurs (on
another newsgroup).  I am drawn to controversies, and that one is finally
sinking its "fangs" into my consciousness (pun obviously intended).
    However, in an effort to broaden my dinosaur horizons, I will briefly
delve back into ornithischians.  I am presently treating the
iguanodontid-hadrosaur mess as cladistically as possible.  Iguanodontidae
including only Iguanodon, followed by Plesion Probactrosaurus, and finally
Family Hadrosauridae (with Ouranosaurus and Altirhinus as basal members).
    However, if there are convincing reasons to transfer Ouranosaurus
and/or Altirhinus to Family Iguanodontidae, I would certainly consider such
a transfer, but only if it is a holophyletic group.  If transferring these
genera would make Iguandontidae paraphyletic, it would still be too small to
be worth the bother.  I save my energy to fight for taxa that are larger and
more paraphyletic.  Even I think paraphyly should be more the exception than
the rule (moderation in all things, even paraphyly).   Anyway, time for some
sleep to recharge my batteries.  Too tired to ramble any more.
        ---Still an ornithischian novice,
                         Ken Kinman
********************************************************

From: "Jaime A. Headden" <qilongia@yahoo.com>
Reply-To: qilongia@yahoo.com
To: dinosaur@usc.edu
Subject: Iguanodontidae and Theropod Boredom
Date: Sun, 1 Jul 2001 21:03:05 -0700 (PDT)

  Sorry, but this list does seem to get a little focused around
theropods, despite the diversity of ornithischians outstripping
theropods in both number and diversity....

  Yet little is done on them....

  Anyway, for a non-theropod topic, I thought it might be
interesting to explore what we could of iguanodontid
relationships, both general to Iguanodontia (*Hypsilophodon* +
*Iguanodon*) and specifically.

  Several taxa are involved, including:

  *Iguanodon* (various species)
  *Altirhinus kurzanovi*
  *Probactrosaurus gobiensis*
  *Ouranosaurus nigeriensis*

  Some hypotheses argue that these taxa form a monophyletic
Iguanodontidae, others that they form a serial relationship to
hadrosaurs, with many agreeing that *Probactosaurus* is a
hadrosaur or next sister group, or with a diphyletic hadrosaurid
grouping. *Ouranosaurus* is regarded as a possible
hadrosaur-like iguanodont.

  The species of *Iguanodon* also seem to be under contention:
*I. hoggi* was proposed as a possible camptosaurid (Norman,
1999, _JVP_ 19(3); SVP-Denver), and *I. bernissartensis* and *I.
atherfieldensis* were conspecific but regional variations, or
even genders of each other. I would like to open this thread in
the hopes of stimulating further discourse on our non-theropods
so that those on the list who work on non-theropods (especially
ornithischians) will not be desensitized to it.

  And is there anyway we can have a thread on sauropods that
doesn't involve some historical they were
landwalkers-not-swimmers idea or anything about their necks... :)

=====
Jaime A. Headden

  Aaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhr-gen-ti-na
  Where the Wind Comes Sweeping Down the Pampas!!!!

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