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RE: Erketu ellisoni online free access
Ah, not quite. Appendix 2 gives the coding for Erketu from the published matrix
of Wilson 2002. Of 234 characters only 18! can be coded for Erketu. That is
7.7% of possible characters! How can anyone tell me that we can assume to know
so much from so little???? Keep in mind that a phylogenetic analysis is simply
a form of statistics. Even Wiens' article notes a decrease in reliability of
phylogenetic results when 75% or more of the data is unknown (his Fig 2). Here
92% is unknown!!!!
Kenneth Carpenter, Ph.D.
Curator of Lower Vertebrate Paleontology/
Department of Earth Sciences
Denver Museum of Nature & Science
2001 Colorado Blvd.
Denver, CO 80205
for PDFs of some of my publications, as well as information of the Cedar
From: firstname.lastname@example.org [mailto:email@example.com] On Behalf Of David
Sent: Tuesday, March 21, 2006 2:20 PM
Subject: Re: Erketu ellisoni online free access
> The data matrix has more question marks than known character states.
Not true. These are just the codings for *Erketu*. The rest is taken unchanged
from Wilson (2002), except for one character state of one taxon explained in
> Nevertheless, the results pretend that we know something about the
> question marks (as if they weren't there).
How so? At worst it lets us apply parsimony to infer what the true states are
-- _after_ the tree has been made.
> There is nothing wrong in science to
> say "I don't know" than to pretend that we do.
But we do know something. We know that, according to that analysis,
*Erketu*(*) is with quite some certainty a somphospondyl. The bootstrap value
of that clade is 89. We can also be fairly sure, though less so, that
*Erketu* is not a member of the smallest clade that contains *Malawisaurus* and
*Alamosaurus*, because that clade has 79 % bootstrap support. These values are
better than almost everything inside the latter clade (51, 56, 60, 70, 81 and
83) and much better than the, one should think, quite obvious Neosauropoda
(less than 50 % -- not shown).
But then I have my doubts about Somphospondyli. It seems to be held together
mainly by its somphospondylous vertebrae... right?
* Meant to be pronounced the French way. The etymology section says "Erketü"
and "Yesügei". -- BTW, in spite of this the paper is totally full of typos.
Some are consistent throughout the text and references, so may be genuine
errors, such as "Tshuihiji" and "*Mamenchisaurus houchuanensis*".