[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Unwin's high horse


Sorry to have to do this in a public forum, but your "wizard of oz"-like
belly-aching is getting tiresome.  Cue Toto. Pull the curtain open.

David Unwin asked: >>And the name of the taxon? Specimen number?

Not wanting to jinx the embargo on publishing, I'll ask you to wait for
the paper. Goading won't help. Patience, please. Promises from the
editorial staff, as mentioned earlier, are less than a month. Your
emails listed many of the specimens. I took a close look at them and saw
flaws in the descriptions. David, unless everyone is entertained by this
thread, let's just drop it until such time as you've read the paper and
the evidence presented therein. You're not going to understand the
situation unless you see the drawings and the captions.

I already can see it's going to be like trying to convince the Reubens
team that Longisquama does not have feathers -- or the Martin/Feduccia
gang that birds are dinos. Such is the power of the paradigm.

Out of respect for your authority on the subject I have earlier
attempted to correspond with you privately on this matter. I have
attempted to offer you the images on the CD, but your email server has
me listed as a Spaminator and bounced back my correspondence. Therefore,
part of the problem is in your lap.

David Unwin wrote:

>>With regard to pterosaur terrestrial ability Peters wrote:

>>Imagine Nyctosaurus _trying_ to walk quadrupedally. The wings are _so_
relative to everything else, that those distal metacarpals hit the
_beyond_ the tip of its beak. It would be like a child trying to walk
with grown-up crutches.<<

First, I reject the argument that because Peters finds it difficult to
imagine Nyctosaurus walking quadrupedally that somehow the whole idea of

pterosaur quadrupedality is flawed. <<

At this point I am convinced that you have not read my papers or emails.
I reiterate. _All _ pterosaurs were capable of both bipedal and
quadrupedal locomotion. In certain taxa, the preferred method was one or
the other depending on morphology. In most ,their standing poses need
not shift at all moving from one form to another. All they had to do was
to drop or raise the elbows. IMHO, it was _that_ easy.

David Unwin also wrote: >>
Secondly, Bennett (1997, JVP tracks paper) has already published an
excellent reconstruction of how Nyctosaurus might have stood and walked
in a quadrupedal fashion supporting itself on the wing-knuckle (please
ignore digits i-iii, apparently Nyctosaurus didn't have them). Moreover,

impressions of the manus at various track sites show that the
wing-knuckle often contacted the ground. Yet another example of good
correspondence between skeletal anatomy/functional morphology and
tracks. <<

"Why, you're not a wizard at all!"
At this juncture I am convinced that you have not read Bennett's paper,
either. Although he did show Nyctosaurus in a quadrupedal pose he wrote:
"This would make quadrupedal locomotion difficult.?At approximately 60º
above horizontal, the animals would be essentially in the upright
bipedal posture proposed by Bennett (1990, 1991, in press) and the
center of gravity would be over the hindlimbs. At this point, the animal
might as well pick up its forelimbs, fold them compactly, and walk

David Unwin also wrote:

Sarah Sangsters work

Peters opined:

>>At the time Sarah was only familiar with Clark's work which was
by my subsequent paper on hinge line analysis Peters 2000 (Ichnos 7(1):
11-41) where I showed a model of a dimorphodontid pes in a digitigrade
pose that did not violate Clark's dictum on metatarsophalangeal line
extension. <<

Unfortunately, it would appear that pterosaurs were not familiar with
Peters (2000) hinge line analysis and, as the tracks show, doggedly
continued to proceed in plantigrade fashion.<<

Didn't read _that_ paper either, did you?  If you did, you'd already
know that hinge line analysis also indicates plantigrady in certain
forms, irrespective of tracks.

Unwin continues: >>
Well, to be fair to
pterosaurs, the construction of the joints in the pes completely
hyperextension and digitigrady as Clark et al convincingly demonstrated
in their Nature paper, so, even if pterosaurs had known about the 2000
study, they still could not have managed digitigrady. <<

And you didn't read the last email evidently. I reiterate: I broke none
of Clark's dictums regarding prevention of hyperextension to produce a
digitigrade pose.

More from Dr. Unwin: >>
More importantly, according to Sangsters' presentation at SVPCA earlier
this year, one of the primary goals of her work on Dimorphodon was to
test the various ideas that have been published regarding the stance and

gait of this pterosaur on the ground. This she has done, for example
using computer based approaches to establish the centre of mass and its
relationship to the hind limbs (way, way in front of the feet -
bipedalism practically impossible), and concluded that Dimorphodon was a

quadrupedal plantigrade. To state that 'At the time Sarah was only
familiar with Clark's work' is not just wrong, its highly misleading and

makes imputations regarding Sangsters work and understanding of
pterosaurs that are unwarranted and offensive. <<

Evidently you don't read my emails to others, either. [Ooops, that's a
good thing!] During private correspondence with Sarah, she mentioned
that she was not familiar with my hinge line work, only that of Clark.
Otherwise I haven't seen Sarah's studies. If, since reading my work in
the meantime she rejects it, then that's another issue altogether.

More from Dr. Unwin: >>
Bennett's website:

I am a (proud) Mac owner (G3), using rather outdated software (Netscape
4.08) and had no problems at all accessing Bennett's website and viewing

all the images. (Incidentally I completely agree with Bennett's
conclusions). So, one might ask, how is it that a computer based
artist, using a machine, software and knowledge of computer graphics
I have no doubt are vastly superior to mine (no irony or sarcasm
intended) was unable to view the images on the same site? <<

As I confessed earlier, I don't know why the pictures didn't pop up.
When I was creating my old website I had similar problems seeing my own
work until I got the bugs out. I'm sure it's just a minor issue. In
private correspondence I have asked Dr. Bennett to send me a few of the
most damning pictures. I'll be the first to confess if I've made a
mistake in drawing or identification. Thankfully I'm not a professor, so
I don't have to defend my work to my dying breath. I can simply change
it to reflect the facts as more data comes in and Science marches on.
However, if Dr. Bennett made an error in identification, in my opinion,
then we can argue about that and hopefully come to a resolution. I'll
let everyone know when that happens.

More from D. U. : >>
More seriously, no one can have failed to notice the numerous
exhortations <<

[this is a wizardy word that means "requests"]

by Peters, in his previous posts, that I provide
drawings/photos of specimens or reconstructions to illustrate the
points that I have made and, since this debate is taking place in a
public arena open to all (well, all with computers and web access), that

I make these images publicly available. <<

Not if to do so would have violated pre-publishing limitations. That's
why they have this thing called "private correspondence." And I look
forward to yours, whenever it may come.

All credit to Bennett therefore
for responding so splendidly by presenting a clear, well argued and
profusely illustrated critique of Peters' claims based on computer
enhancement of published pictures. <<

If the tables were turned, and I had publicly broadcast pre-published
drawings that you had entrusted to me, I can only imagine the outcry.

So, why is it, now that we have some
illustrations that we can all see and comment on, that Peters, who made
the loudest demands for exactly this state of affairs, should
insist that images be removed from the web site, thus preventing any
proper public debate? <<

The issue here is prior consent of copyrighted materials. Chris could
have said, "Listen Dave, let's have a public airing of this issue. Mind
if I create a website based on your work?" He didn't. I'm proud of my
work and love to discuss it. From what I could see Chris edited the work
by removing the color identifying the bone shapes. That's not right
either. I'm still eager to see the opposing evidence.

D.U. concludes: >>

If this discussion regarding what can or cannot be
seen in fossils (started by Peters' 'Roadkills' thread) is to remain in
the scientific realm the pictures should stay on the site. The
alternative, as Chris suggests in his conclusions, is that if these
figures are unable to withstand public scrutiny then we must reject them

and any conclusions based on them. <<

Does anyone else here see the "public lynching" attitude displayed by
Dr. Unwin's choice of words? Even if there some errors therein [still
waiting for the evidence] then does that warrant complete rejection of
every pixel? Where is the calm and scientific picking apart of the
errors and embracement of the new data?

Your protests are too loud, sir.

In my opinion, ladies and gentlemen, we're seeing something akin to a
supernova explosion as a dying star breathes its last breath. In other
words, a swan song for the broad wing hypothesis.

Looking forward to all your comments in January.

David Peters
St. Louis

PS. Regarding D. Varner's recent posting regarding tracing copyrighted
pictures: As far as I know, tracing is still legal. Photocopying for
private use is still legal. It's considered Fair Use. Dissemination via
photocopying, as in a classroom setting, is illegal. Dissemination via
the web of copyrighted materials without prior permission is illegal.
Let's hope the good people at Salamander Ltd, Wellnhofer's publisher,
don't find Chris's website before it goes down.