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Re: was ... Jaime. Now: M. Baeker has a problem with phylogenetic analysis

On Jun 20, 2006, at 1:20 AM, Martin Baeker wrote:

Just tell me how it would be possible to demonstrate that a juvenile
belongs to a parent if they are to look completely different.

Try to not use the all inclusive phrase: "completely different". Because even
elephants and flies are symmetrical. If you find it too difficult to come up
with an adult/juvenile pterosaur pairing, go to the literature and see what
forms Wellnhofer and Bennett have promoted as adults and parents of the same
genotype. Then expand the universe of taxa to include all pterosaurs and
you'll find that rather than matching parents, the so-called 'juveniles'
actually form series that fill phylogenetic gaps between taxa. It's not an
isolated incident. Happens about six times.

So, once again, your argument is as follows:

If I assume these small pterosaurs are adults, I get a cladogram I
like, therefore they are adults.

Not necessarily. But they'll substitute nicely as adults. Martin, it would be helpful for you to see some phylogenetic series to scale as I can provide you privately (no pictures allowed on the DML). Then you'd see the gradual progression in morphology and size. Then you'd see that if any of the tiny pteros was a juvenile the adult version would stand out like an exceptional giant.

In pterosaurs they do, as embryos tell us. Chiappe and Co. told us one embryo
was Pterodaustro because it was found with and looked like adult Pterodaustro.

Thanks for pointing me to this article, I hadn't looked at it, at least not recently. But read the nature article closely:

"The relative sizes of limb elements of the specimen, which give an
estimated wingspan of 27 cm, are similar to those of early juvenile
specimens of Pterodaustro and agree well with allometric observations
based on a growth series of this taxon indicating negative and
positive allometry for the proximal (humerus and ulna) and distal
(metacarpal IV) portions of the wing, respectively."

This translates as: The embryo does *not* look like an adult
pterodaustro wrt limb proportions, but the juveniles known provide us
with enough knowldege of *how the bones grow differently* to ascertain
this as a pterodaustro (and the filter-teeth surely help.)

But if you would now code this pterodaustro as an adult for use in a
cladogram, the differences in the limb proportions would place it not
at the same place as the adults - you would get a nice series from the
embryo through juvenile to the adult.

all true, but not to the extent that you might think. Baby Pterodaustro still nests with the mama. The differences, in a larger holistic sense, are not enough to bump baby Pterodaustro out of the nest.

It can't if you plug in units (specimen or species) *that differ in
more than just phylogeny*.

Example please.

You don't really need that, it is obvious from the theory behind the cladogram. You can plug in *anything* into PAUP if coded correctly and it will produce a cladogram. Try car brands, languages, whatever. What you will get is an ordering of the things you plugged in - this ordering can be assumed to be phylogenetic if and only if phylogeny is the only thing what the units you plugged differed in.

And even enigmas find their rightful place.

Phylogeny is easier than you think.

I'm afraid it's more difficult than *you* think...

No. Just find data for 34,000 boxes and you're in. All prior tests of the clade were much, much, much smaller -- and therefore easier.

I think your comments shed light on your outlook and prejudice, Martin, that you make your pronouncements without looking at my data, my matrix or my tree. Therefore, you are exactly like the priests who refused to look into Galileo's telescope. I'll stop there.



                   Priv.-Doz. Dr. Martin Bäker
                   Institut für Werkstoffe
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                   38106 Braunschweig
                   Tel.: 00-49-531-391-3073
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                   e-mail <martin.baeker@tu-bs.de>