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RE: Stenopelix valdensis



Denver Fowler wrote-

I see Mickey has chosen to continue his insulting
diatribe against Bob Sullivan. I don't think the tone
of his responses are appropriate on an open web forum,
especially for an unpublished amateur statistician
criticizing peer-reviewed articles by a qualified
palaeontologist.

Ouch. Reduced to a statistician, and a seemingly unqualified one at that. ;)


Mickey's intent on insult was
apparent from his lack of response to my previous
posting, and continues in his most recent post.

Er... which post of yours didn't I reply to? I replied to your June 23rd post, if that's what you mean.
http://dml.cmnh.org/2006Jun/msg00418.html


Of
course, you are welcome to disagree with somebody's
research, heck I disagree with bob alot, especially on
taxonomy; I find that most qualified scientists
observations are astute and worth noting; although
sometimes I would disagree with their interpretations.
Certainly, even for people I disagree with, I wouldn't
stoop to calling anyone's research 'worthless'.

I called his reasons (for making Stenopelix Ornithischia incertae sedis) worthless, not his research.


Maybe
Mickey would be so kind as to provide us with a list
of other authors whose work he finds 'worthless';

Well since you asked so nicely...
http://dml.cmnh.org/2002Sep/msg00774.html
http://dml.cmnh.org/2005May/msg00317.html
http://dml.cmnh.org/2005Oct/msg00222.html
;)
Okay, the latter actually had some valid material from Lingham-Soliar, but Feduccia's parts were sad. And these workers have generally done some worthwhile work (I hear Martin's sabertooth cat studies are fine), but the papers I reviewed weren't at publishing standards in my opinion.


I am
sure it would be of interest to many people. Perhaps
Mickey's insulting tone can be attributed a little to
overenthusiasm for his cladistic method, rather than
being truly insulting to Bob, unless he would like to
correct me.

Your first reply to my pachy critique also emphasized my cladistic philosophy, as did Sullivan's reply (I believe he accused me of cladistic zealotry or somesuch). But many of my problems with Sullivan, including these Stenopelix issues, do not have to do with unweighted numerical cladistics.


We have a poor understanding of basal Ornithischian
phylogeny, and as a result it is not clear which
characters of marginocephalia, especially postcranial,
might be plesiomorphic (since we don;t have a well
resolved outgroup.. the heterodontosauria are not well
understood either). I am sure this is what bob is
suggesting in his diagnosis of Stenopelix. It might
well be a basal pachy, or something else more or less
derived; a proper reanalysis of the skeleton should be
undertaken in order to acertain this.

But until someone _shows_ the specific characters suggested to place Stenopelix in Pachycephalosauria are ambiguous in outgroups, this is an empty statement. You can't just say "their absence and/or presence in non-pachycephalosaurid taxa are not well-established" without going into detail, and justify removing Stenopelix from Pachycephalosauria based on that. I could just as easily claim Alvarezsaurus' supposed characters shared with Patagonykus and mononykines are not well established in non-alvarezsaurid taxa, and it would be just as valid as Sullivan's statement. That is to say, not demonstrated at all. Now if either of you want to _show_ which outgroups have which of the three pachycephalosaur characters Sereno used, we might get to the point where placing Stenopelix somewhere else is warranted. Notice none of this has to do with unweighted numerical cladistics.


While you're at it, explain how Sullivan's logic is justified when he says that because postcranial characters "are not readily preserved in most pachycephalosaurid specimens", they are only 'weak' evidence for placing Stenopelix in the clade. That's equivalent to saying because integument is preserved in so few dinosaurs, the evidence for placing an isolated stage III (fully developed) feather in Coelurosauria is weak. Character distribution is what matters, not frequency of preservation. Notice this doesn't involve unweighted numerical cladistics either, although PAUP does treat it the logical way.

* I don't mean to sound harsh here, but neither you nor Sullivan have offered any actual defense against my specific critiques. Instead, I just get accused of being a cladist and 'unqualified', which is annoying because few of the criticisms involved cladistic methodology, and I shouldn't need a PhD to point out flaws in arguments.

And in reply to
another of Mickey's previous points, I know of a
number of dissenters of the Marginocephalia, and of
Stenopelix's alleged affinities/characters.

Do these dissenters know of Yinlong? Do they have an alternative phylogeny? Is it supported by a comparable amount of characters? Here I'm valuing cladistics, yes. I don't know what else you'd use.... phenetics? Stratigraphy and biogeography perhaps, but those are limited for dinosaurs. Shared derived characters are pretty much all there is.


The plain truth is, the affinities of basal
ornithischians likely can only be answered by recovery
of new specimens and/or analysis of actual material,
of which I suspect, Mickey has done neither.

An actual good analysis would do wonders, I agree (maybe Butler's will be up to par). But I'm not suggesting or defending a topology as much as I'm saying Sullivan's reasons for rejecting that topology aren't justified.


Some of us are actively out collecting specimens to
help us understand the situation better. in April of
this year I helped collect material from the Shishogou
Fm in China with the German expedition; in May I was
surveying recent finds from the Lower Cretaceous of
the British Wealden; in June I was helping dig in the
Judith River, MT; and the day after tomorrow I head to
New Mexico with Bob to collect from the Late
Cretaceous there. We have recovered a large amount of
material which is in the process of being described,
and will continue to add to this in future years. You
can criticise the results of these analyses when they
are published, or maybe you could spare some time away
from the computer to come help dig. There are plenty
of field programmes out there desperate for extra
pairs of hands. It's time well spent away from the
computer.

And maybe you could spend some time performing phylogenetic analyses. Or not. We all have different areas of interest within paleontology. I like anatomy and phylogeny. I'm bored to tears when it comes to taphonomy or ichnology. I did spend six weeks at field camp in Montana for a class, and didn't enjoy it much at all. Maybe if it were excavation I'd like it better (we mapped geological formations- yawn). But I bet I'd still prefer to be working with PAUP (whch is also affordable to me, unlike travel to fossiliferous localities). Denigrate that all you like, but we all have our places in this field, and we've seen what can happen when people stray outside their specialty.


Mickey Mortimer