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Re: Lü and Li 2006, a review


On Jun 6, 2006, at 4:14 PM, Jaime A. Headden wrote:

David Peters (davidrpeters@earthlink.net) wrote:

<1. Well, the choice of the outgroup taxa dooms the base of this study from the
start. Pterosaurs are lizards, not archosaurs as shown by a cladistic analysis
2 to 14 times larger and more inclusive than any prior attempt at classifying
amniotes.>

I doubt whether the outgroup would have influenced the deeper arrangements of
pterosaurs much at all, though it might shift the base around a little.

So, Jaime, why make a red herring negatory comment if you are in tacit agreement with my statement? It makes you look bad, my friend. Argumentative, just for the sake of being so.

<2. 34,000 most parsimonious trees were found and that's because the limit of
the Max Tree was set at 34,000. Wow. That should be a huge red flag that
something is rotten in this tree and more work needs to be done.>

If I got to 34,000 max trees on my result, I'd realize that little would
result in fewer trees unless I started un-zeroing entries, which in the
authors' cases would mean pretending that some specimens were clearer or more
complete than they really are.

You're guessing and you're guessing wrongly, speaking as one who has done the work. I would be more convinced that these workers had done their work if I had seen labeled tracings and reconstructions. Roadkills are devilishly mysterious, until the CSI guys dissect the scene. Adding characters and taxa would solve their massive MPT problem. The data is available. They just took the easy path by adopting Kellner's work.

<3. As usual, the highly derived pterosaur, Rhamphorhynchus, is shown to be the
sister group to the classic 'Pterodactyloidea' when anyone with an eyeball
would be hard-pressed to find a synopomorphy or two uniting the two. In an
unpublished cladistic analysis of greater breadth, Rhamporhynchus is a highly
derived dead end leaving no progeny and the pterodactyloid grade arises four
times by convergence from dorygnathids twice and via basal dorygnathids, from
scaphognathids twice.>

It's a "highly derived dead end" in EVERY cladistic analysis to include it,
which comes from the nature of it's peculiar cranial anatomy.

Not so here, my friend. Show me one study that has Rhamphorhynchus as a dead end without sister progeny. It's always the last bus before the transfer.

Less confusing, I
am sure, is the more plesiomorphic postcrania.

"I am sure" is a well-known weasel phrase for "I have room for for doubt but don't want to express it." Better to leave out this phrase. And the postcrania is not as plesiomorphic as you might assume. In my study, there isn't just one Rhamphorhynchus, but a whole bush leading from Campylognathoides alone, with lots of variation in every part of the body.

Then again, pterosaurs like
*Dorygnathus* and *Sordes* has very similar jaws and skull structure,

And for good reason. Sordes is a short-tooted type of Dorygnathus, as are all subsequent pteros. Not the other way around, which is how Lü and Li portray them.

so I
doubt Rhamphorhynchidae is very incoherent in the current pterosaur
environment.


??? You've phrased that incoherently.

As for the polyphyletic treatment of some clades, one must wait
for testable, available results to consider claims of such oddity, if indeed
such would exist.

Again, ???

<5. No tiny pterosaurs (typically known from numbers rather than names) were
included, which also screws up the results royally. Tracings of pterosaurs in
eggs show that their proportions do not differ greatly from their parents, so
any so-called assignments of short-rostrum 'juveniles' to long- rostrum 'adults'
are false and misleading.>

These specimens are not included for what, it seems to me, is a VERY good
reason: they are considered juveniles by just about every pterosaur worker out
there.

That's tradition and paradigm. Test them. No one has yet. Don't be afraid to. It's not that much work.

Not because they assume it to be true, but because a good deal of work
has gone into considering them and relegating them as juveniles, even if
taxonomic assignment can be shaky (which it may be).

Not so, small size was assumed to represent juvenile status and long- winded explanations were devised to promote the idea despite changes in bone, tooth and proportion that could just as easily, and it turns out, more readily, to have been phylogenetic. If I were wrong, I should be the one with 34,000 MPTs. Right? Right? No I have one tree, and all the sister taxa blend, like Mr. Darwin said they would.

Only one person it seems
considers them adults, and for reasons that it would appear NO ONE agrees with
him on (that no one referring to pterosaur workers or anyone who's looked into
the situation).

Many discoveries, from continental drift to a heliocentric solar system, were made by mad men working alone with various sorts pointing fingers and calling names. And you, Jaime, are one of the sticks in the mud, as you'll discover someday.

Finding proof these aren't juveniles would be considerable, but
so far, no data demonstrating this has been published.

Not for lack of trying. The strategy now is to publish and finished revision of the Amniota, then work to the branches.

The paper Dave published
on a few juveniles found inside eggshells are just that, juveniles inside
eggshells.

At the time, you'll remember, the specimen inside the eggshell was the size of a typical adult anurognathid. It's still an anurognathid. Only a juvenile of a much larger one, only one of which is known in the adult form. This is called making an honest mistake, which I was glad to announce at the discovery of the second and third pterosaur eggs. Altogether this is called progress. Or science.

Additionally, "ephemera" (that which disappears with a second look)
do not prove the adulthood of an adjacant specimen.

I submit to you, Jaime, that the bits and pieces of the entire baby pterosaur are present and visible inside of each egg. Actually, the bones are 'packaged' rather nicely in their original containers. I have traced them. All the bones connect as they should. The work has been widely available for years.

So, there is good reason
not to include these specimens in a matrix.

Yes, put your head in the sand and avoid testing when it would be so easy to do so. And so rewarding. I encourage you to put any tiny ptero in a matrix and see where it falls. A dozen would reveal more though.

If anything, this inclusion is what
I suspect is resulting in the rather topsy-turvy result of "pterodactyloidea"
and non pterodactyloid pterosaurs in Dave's own analyses (testing to this idea
would require REMOVING THEM to see the results).

Removing the tiny pteros does indeed bounce the cladogram back to a ladder -- but then you have to deal with sister taxa that do not blend as Darwin said they should.

There is something deliciously wonderful about lifting the veil of ignorance and seeing unexpected truth after years of work. There is also something devilishly charming about certain folk who play their part so well and create unnecessary drama about such trivia. 


Back to you.

DP


  Cheers,

Jaime A. Headden
http://bitestuff.blogspot.com/

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

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