RE: FW: Dracorex's phylogenetic position examined with science

[Denver Fowler <df9465@yahoo.co.uk>]

I think it is pretty fair to say that the "examined
with science" tag to the email title should have read
"examined with cladistics". The particular choice of
wording of the email title could be read as a personal
attack on Bakker & Sullivan and their credibility as
'scientists'. in this case it has certainly caused
offence, whether intentionally or otherwise.

There are methods of testing phylogenetic hypotheses
other than cladistic 'objective' character analysis,
and it should be remembered that these can directly
complement or add to said cladistic analyses (eg.
non-cladistic description highlighting new character
states/ innaccuracies in current ones / stratigraphic
occurrence etc). There have been more than a couple of
recent cases where papers have been accompanied by
innappropriate/innacurate cladistic analyses, and this
was roundly criticized, yet sadly this practice
continues. In this particular case a cladogram was not
provided with a published article, as the authors felt
the data was not robust enough, and they were
ridiculed for this.

I don't necessarily see myself as an anti-cladistic
person, but there are times when the significance of
such work is overstated (especially when contrasted
against specimen collection and analysis). I'm not
about to perform a phylogenetic analysis (i am too
busy out in the field helping collect new specimens
for analysis), but surely the most scientific way to
refute Sullivan/Bakker's claim would have been to use
their own dataset to prove them wrong? It's pretty
clear that Sullivan & Bakker don't consider Williamson
& Carr's character matrix as correct.

Denver.

--- Michael Mortimer <mickey_mortimer111@msn.com>
wrote:

> Bob Sullivan wrote-
> 
> >     Mortimer has misrepresented my paper which
> primarily was
> >intended to be a taxonomic review (not a cladistic
> analysis) of
> >pachycephalosaurids based on my examination of the
> material. As far as
> >the phylogenetic analysis he proposes, I reject it
> on the grounds that
> >he has not personally studied the material and  is
> apparently just
> >combing the literature for characters without
> properly assessing them.
> 
> As Tim pointed out, your paper did make phylogenetic
> claims, regardless of 
> its primary purpose.  It and the Dracorex papers
> both had sections dedicated 
> to phylogenetic implications.  I want to point out
> that I agree not every 
> paper needs a cladistic analysis.  This was not my
> problem with Sullivan's 
> or Bakker et al.'s papers.
> 
> It's true I didn't examine any material firsthand. 
> The characters were just 
> those of Williamson and Carr (2002) though.  Like I
> said, the point was not 
> to test your ideas regarding Prenocephale or the
> sister group to 
> pachycephalosaurins vs. theirs.  I didn't include
> your characters, so that 
> couldn't be tested.  The point was that the
> homoplasic Dracorex is not the 
> problem for cladistics it was presented as, nor does
> its combination of 
> characters mean we should start questioning the
> standard results of 
> pachycephalosaur phylogenetic analyses.  In fact, by
> putting Dracorex into a 
> previously made analysis, I tested this even better
> than if I had used my 
> knowledge of Dracorex when creating a novel matrix. 
> Williamson and Carr's 
> matrix was 'unprepared' for Dracorex, in a way, yet
> it still handled the 
> taxon just fine.
> 
> >       The issue at hand, as I see it, is there is
> little compelling
> >evidence to produce a robust phylogenetic analysis
> vis-a-vis cladistic
> >analysis at this point in time as most of the
> material is too
> >incomplete. I find his comments regarding my work
> extremely offensive.
> >His implied assertion that cladistic methodology is
> the only way to do
> >"science" (no matter how poor the data are) is
> absurd. I note the
> >approach that he advocates only produces a
> "cladogram du jour" nothing
> >more. This is cladistic zealotry, not science. It
> is clear that he is
> >not critically assessing the data. He selectively
> chooses to embrace
> >(some) previous interpretations that result in a
> nice (albeit
> >simplistic), neatly nested, hypothetical hierarchy.
> He fails to
> >understand, in the fog of his cladistic zealotry,
> that cladograms are
> >nothing more than phylogenetic hypotheses (subject
> to revision as more
> >data are incorporated), they are not necessarilary
> truth (science).
> 
> Where to begin...  It's true people haven't utilized
> much data yet when it 
> comes to determining pachycephalosaur phylogeny. 
> But this doesn't mean we 
> shouldn't try with what we have.  Maybe the data
> really are too poor at the 
> moment, but at least a cladistic analysis gives us
> something tangible and 
> somewhat objective that can be tested against
> additional data.  I don't view 
> the result of any cladistic analysis as 'the truth',
> since I am well aware 
> of how labile they are (depending on which taxa,
> characters, states, etc. 
> are included).  They are merely the best hypotheses
> available, given 
> currently utilized data.  And this is what science
> is.  Science is not truth 
> (which we may never know).
> 
> >The
> >fact is that there is real disagreement over the
> validity of the
> >Marginocephalia and the interpretation that
> Stenopelix is a
> >"pachycephalosaur."
> 
> I haven't seen such disagreement in the literature.
> Marginocephalia seems to only get stronger,
> especially with the discovery of 
> Yinlong.  The latter ironically lacks a parietal
> shelf, suggesting you may 
> be right (albeit for the wrong reason) in claiming
> this was convergent in 
> derived ceratopsians and pachycephalosaurs. 
> However, its mosaic of 
> pachycephalosaur and ceratopsian features makes this
> irrelevent.
> As for Stenopelix, every recent analysis I've seen
> has placed it in the 
> Pachycephalosauria.  I haven't seen any
> contradictory evidence (none was 
> given in your paper, certainly), and stand by my
> statements regarding the 
> flaws in your rationale for excluding it.  But as I
> also said, with the 
> recent discovery of Yinlong, we should reexamine
> Stenopelix to determine if 
> its pachycephalosaur characters are also found in
> basal ceratopsians.
> 
> >His failure to recognize that the genus
> >Sphaerotholus is a junior synonym of Prenocephale,
> and Ornatotholus is
> >not distinct from juvenile Stegoceras, is
> illustrative of the cladistic
> >typology that he embraces. I do not find this (his
> approach) to be
> >credible science. Wishing it does not make it so
> and I reject his
> >embracement of this antiquated notion that all
> "flat-headed
> >pachycephalosaurid taxa are inherently primitive.
> One can manipulate the
> >data to effect the resulting tree.
> 
> One can indeed manipulate the data to affect the
> outcome.  But at least in 
> cladistics such manipulation is transparent and has
> an objective effect on 
> the tree.
> The Prenocephale/Sphaerotholus issue was
> specifically not tested by my 
> analysis, as I previously said.  Moreover, it's a
> subjective decision to 
> synonymize them even in your (2003) phylogeny, as
> the American species are 
> in a clade sister to P. prenes.  And it's especially
> contentious if you keep 
> Tyolocephale separate, as I previously said, since
> only some of your trees 
> place P. prenes closer to the American species than
> to Tylocephale.
> I never claimed Ornatotholus was distinct from
> Stegoceras.  I specifically 
> wrote both you and Williamson and Carr interpret it
> as a juvenile 
> Stegoceras, and that exclusion of it and the other
> juvenile OTU 
> (Wannanosaurus) did not affect the cladogram.
> I also never claimed all flat-headed
> pachycephalosaurs were inherantly 
> primitive.  The fact flat-headed Dracorex was
> resolved as a 
> pachycephalosaurin should have made that clear
> enough.  My point was that 
> just because some flat-headed pachycephalosaurs
> (Dracorex) are derived from 
> dome-headed taxa, that does not mean all others
> (Homalocephale, Goyocephale) 
> are.  I stand by my statements that your reasons for
> deriving the latter 
> from dome-headed taxa are flawed.  It would be nice
> to hear you defend them.
> 
> Mickey Mortimer
> 
> 
> 



                
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