[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

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)

__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com