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


On Jun 19, 2006, at 7:12 AM, Martin Baeker wrote:

David, you need to show one case, and one case only, of a juvenile
that does not look like an adult of the same genus or larger clade - and
doesn't resemble some other adult taxa that it is totally unrelated to. If
you
can, and if you do, then we can fight like rats in a cage about the
details
and evidence. Until then you have no evidence and your arguments are based
on
rhetoric and examples from other unrelated clades. Stick to pterosaurs.


How the heck should this be possible? Unless you have a complete
growth series, how could you identify a juvenile as belonging to a
certain adult if it looks not like an adult of the same clade?

Exactly my point.
You're all trying to pull a rabbit out a hat.


No, it is not your point (are you deliberately misunderstanding me?).

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.

What you're promoting is similar to: baby crows become adult hawks. Or baby
seagulls become adult plovers.

Fledglings usually *do not* look like parents.

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. The first egg found was identified as ornithochierid based on the length of manual digit 4.1 which reached the elbow. The authors did not take into consideration that in some anurognathids this morphotype is also present. More details revealed it to be an anurognathid. It doesn't match any known adult anurognathid, but it can be nested in the family comfortably. The third embryo in an egg is an ornithochierid. The long low skull is preserved, among other characters. It most closely resembles Haopterus, but deserves a genus of its own.

Just include all pterosaurs and let PAUP find the relationships. 

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

Example please. 

In every tree you create with PAUP it is *assumed* that what you get
is a phylogenetic relation. If you plugin, say, me, my daughter, a
(unrelated) friend of mine and his daughter, I'm sure (although this
is a thought experiment) the two children will cluster together and
will probably be basal to me and my friend (depending on what you
chose as outgroup). (If you don't believe it, please try - I would, if
I had access to PAUP.)

The above problem is easier to solve the further away you are genetically from your neighbor. If one has an ancestry in Europe vs. Africa or Asia, well, I think you get the picture. If it is your brother, your niece and your daughter we are testing, well, it becomes more difficult. Perhaps unless one of you is especially tall, big-boned, red-headed or whatever.

Phylogeny is easier than you think.

David 

Martin.



                   Priv.-Doz. Dr. Martin Bäker
                   Institut für Werkstoffe
                   Langer Kamp 8
                   38106 Braunschweig
                   Germany
                   Tel.: 00-49-531-391-3073
                   Fax   00-49-531-391-3058
                   e-mail <martin.baeker@tu-bs.de>