RE: a closer look at Hanson 2006, Mortimer response

[David Peters <davidrpeters@earthlink.net>]

<<David Peters wrote-


    Above I have listed many 'bumps' in your 'blend'. If your  
results produce a hundredth of 34,000+, then your results produced  
340 trees. Right? That's still too many, and more than one, which is  
the number you are competing against.


A comment regarding an impression I get from you, David- the number  
of most parsimonious trees found by PAUP is not indicative of the  
accuracy of the results. A large number of most parsimonious trees  
merely means the analysis lacks the characters needed to place  
several taxa unambiguously. It's possible to make a single MPT that's  
grossly inaccurate due to not including conflicting characters, not  
ordering characters, ignoring ontogeny, etc.

Mickey Mortimer>>

Mickey,

A metaphor for what you are saying is: "Don't cross the street. You  
might get hit by a car." Many referees do the same thing to  
everyone's frustration. Without saying so specifically they throw out  
such general red herrings and orange cones by saying essentially:  
"It's possible that what you are doing is in some unspecified way  
dangerous."

My single MPT is chronologically accurate, avoids untenable  
reversals, puts derived characters at the tips of branches and bottom  
line: you can  line up the taxa in a visual spectral blend like  
rhipidistians emerging from the swamps and morphing into humans  
lurching over computers. It passes any test you can put upon it. Add  
as many characters as you wish. Add as many taxa as you wish. Order  
what you want. But remove the little ones and you're sunk. So you  
must ignore ontogeny in this case. And for good reason.

Also, you should know that a cladogram of this size is extremely  
robust. You would have to show that dozens to hundreds of characters  
were coded incorrectly -- and not only that, but the the corrections  
ALL would tend to push the tree into a different direction. That's  
because if an error is found, it might (50/50) actually strengthen  
the tree.

Now from you,  I need an example of how ignoring ontogeny destroys  
trees. AND I need you to show me one example of a baby pterosaur that  
does not look like its parent (you need to come up with two  
specimens) -- and this baby pterosaur cannot look more like some  
other pterosaur. That's the challenge. Anyone who claims No. 9 is a  
baby Pterodactylus and not a minute variation of Scaphognathus will  
have to do so scientifically, perhaps with a cladogram.

The smallest known pterosaurs, I remind you, are no smaller, nor in  
any parallel universe different than the smallest known adult birds  
and bats. They are volant from the time they leave the egg.

I also remind you that the smallest adult lizards can fit comfortably  
on a dime.


David Peters
St. Louis