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RE: a closer look at Hanson 2006, Mortimer response

<<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>>


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