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Re: Lü and [J]i 2006, a review
I've copied my apologies to the top to avoid useless hard feelings:
Sorry for my direct tone. I just want to be really sure that my point gets
across. I also apologize for the likely culture shock (Americans seem to get
encouragement and praise throughout their lives, while Europeans generally
think that passionate people -- like you -- don't need any additional
encouragement and feel that praise without a little "but" here and there
cannot possibly be serious*) the impact of which I have certainly
* As educational approaches, both have interesting advantages and
<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
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.
Why? Most scientists actively look for nits to pick when given the
opportunity. Attention to detail is, generally speaking, very useful in
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
Basics of cladistics:
1. Cladistics is completely incapable of recognizing ancestors as such. It
RECONSTRUCTS HYPOTHETICAL ancestors -- they sit at the nodes, not at the end
of any terminal branch.
2. If an OTU has a zero-length branch (means, no autapomorphies) and its
geological age fits, then it ENTERS CONSIDERATION in the search for an
ancestor. This is, however, not proof -- we may have overlooked any number
of autapomorphies that, for example, didn't fossilize.
3. From 2., it follows that science can show that something is NOT the
ancestor of anything known, but it cannot show that something IS the
ancestor of anything known. Science can disprove, but not prove. Therefore
cladistics is completely incapable of recognizing ancestors as such.
4. Worse yet. All cladistics programs I'm aware of don't display a
zero-length branch as having zero length unless you have told them to
display all branch lengths. In other words, the programs are incapable of
putting an OTU at a node. Every OTU, even if it truly is an ancestor of
another OTU (or several), will INEVITABLY get its own terminal branch. I can
also express this the other way around: if read literally, no cladogram you
have ever seen contains an ancestor. The claim that there are cladograms
which show *Rhamphorhynchus* as an ancestor of anything _is wrong_, because
it's a contradiction in terms.
Sorry, but... I can't escape the conclusion that either I have majorly
misunderstood you (in which case I apologize) or that you don't know how to
read a cladogram. _In the latter case_, you are in grave danger of doing
pseudoscience because _you're doing cladistics without understanding what
Again, sorry for my direct tone. I just want to be really sure that my point
gets across. I also apologize for the likely culture shock (Americans seem
to get encouragement and praise throughout their lives, while Europeans
generally think that passionate people -- like you -- don't need any
additional encouragement and feel that praise without a little "but" here
and there cannot possibly be serious*) the impact of which I have certainly
* As educational approaches, both have interesting advantages and
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."
I interpret it as "I can't read your mind, so I don't know what exactly you
would find more confusing."
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
With more or less juvenile proportions and, importantly, more or less
juvenile bone histology (number of LAGs, proportion of fibrolamellar and
Haversian bone, presence of unfinished bone surface, presence of external
It seems to have escaped you that actual serious research on pterosaur
ontogeny has been done. That's odd, because I know you read the Journal of
Vertebrate Paleontology. What am I missing?
so I doubt Rhamphorhynchidae is very incoherent in the current
??? You've phrased that incoherently.
Probably in-co-herent has its literal meaning here, "not sticking together",
and thus means "polyphyletic"...
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.
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, not necessarily. The number of MPTs depends on the exact data matrix.
No I have one tree,
and all the sister taxa blend, like Mr. Darwin said they would.
Like Mr. Darwin said they would _if the fossil record were complete_.
Don't rely too much on "blending", on superficial morphological
intermediates. I remember well the precladistic attempts to derive
Tyrannosauridae from *Allosaurus*, with e. g. *Acrocanthosaurus* as an
intermediate that blended in very, very nicely. Turns out people had looked
at far too few characters, even before things like *Stokesosaurus* were
widely acknowledged as tyrannosauroids.
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.
_Now_ you _really_ sound like a pseudoscientist. You know, "in order to be
the next Galileo, it is not enough to be persecuted by an orthodoxy. You
also have to be right" -- Carl Sagan, or wait, I forgot who said it first.
And you, Jaime, are one of the
sticks in the mud, as you'll discover someday.
I'll try to test that...
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.
Fine -- I'll wait for the paper.
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
I encourage you to put any juvenile of anything into the same matrix as its
parents. In many cases the babies will be closer to the root of the tree
than their parents -- because they have not yet developed all apomorphies
that their parents show. Apes would be a funny test case, with us being so
Wait! One word: Aublysodontinae.
There's also a very interesting paper called "Ontogeny discombobulates
phylogeny" about this problem in salamander phylogeny (Systematic Biology,
February last year), but of course salamanders with all their metamorphosis
are a more extreme case than any amniote.
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.
If -- the -- fossil -- record -- were -- complete. The pterosaur fossil
record is quite pathetic, as I'm certain you agree.
There is something deliciously wonderful about lifting the veil of
ignorance and seeing unexpected truth after years of work.
Stop using the word "truth", _please_.
There is also something devilishly charming about certain folk who
play their part so well and create unnecessary drama about such trivia.
Don't forget to play your own part. Go ahead and show that your tiny
pterosaurs are adult. Tricking oneself into seeing doubly impossible*
"ephemeral juveniles" around them does not count.
* A completely unossified terrestrial vertebrate of that size would be
hyper-mega-rhachitic at best, and uncalcified cartilage cannot preserve in
ordinary Konservatlagerstätten -- you'd need an oil sand at the very least,
if not outright ice.