RE: Erketu ellisoni online free access

[Ken.Carpenter@dmns.org]

Nevertheless, the results pretend that we know something about the
question marks (as if they weren't there). The fact that the cladogram
matches a known cladogram is all the more reason to be skeptical since
it supports a preconceived idea. There is nothing wrong in science to
say "I don't know" than to pretend that we do.


Kenneth Carpenter, Ph.D.
Curator of Lower Vertebrate Paleontology/
Chief Preparator
Department of Earth Sciences
Denver Museum of Nature & Science
2001 Colorado Blvd.
Denver, CO 80205
 
Phone: 303-370-6392
Fax: 303-331-6492

for PDFs of some of my publications, as well as information of the Cedar
Mountain Project: 
https://scientists.dmns.org/sites/kencarpenter/default.aspx
++++++++++++++++++

-----Original Message-----
From: Jaime A. Headden [mailto:qilongia@yahoo.com] 
Sent: Tuesday, March 21, 2006 1:07 PM
To: dinosaur@usc.edu
Cc: Ken Carpenter
Subject: RE: Erketu ellisoni online free access

Ken Carpenter (Ken.Carpenter@dmns.org) wrote:

<The paper shows exactly the reason why every paper does NOT need a
cladogram.
The data matrix has more question marks than known character states.
This is a misuse of a valuable tool.>

  Various studies of matrices with and without taxa with lots of "?"
codings show that they can have a positive effect on reducing trees and
character/taxon resolution and can be useful in pulling taxa together
due to apomorphies, rather than collapsing due to unknowns. As recently
as 2000, studies also appeared in _JVP_ (especially Wilkinson, 2003)
regarding mostly-? taxa which allows one to study their use and
usefulness relative to the matrix as a whole.
The conclusion was largely that taxa with large ? content are not
detrimental, but can be positive. As shown with Ksepka and Norell's
analysis of *Erketu*, the phylogeny was resolved, matches that of
Wilson's topology into which it was plugged, and does not reduce our
knowledge of the phylogeny by its inclusion.

  Weins, J. J. 2003. Incomplete taxa, incomplete characters, and
phylogenetic
   accuracy: is there a missing data problem? _Journal of Vertebrate
   Paleontology_ 23(2):297-310.

  Wilkinson, M. 2003. Missing entries and multiple trees: instability,
   relationships and support in parsimony analysis. _Journal of
Vertebrate
   Paleontology_ 23(2):311-323.

  Cheers,

Jaime A. Headden
http://bitestuff.blogspot.com/

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

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