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RE: Coelurosaurian phylogeny: model-based methods and parsimony



> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] On Behalf Of 
> David Marjanovic
> Sent: Wednesday, February 20, 2013 10:01 AM
>
> > Despite this, some systematists are suggesting superiority of these
> > model-based methods over maximum parsimony based on, for example,
> > increased resolution
> 
> Cynical interpretation of increased resolution: character conflict is hidden.

Not only cynical: informed, and scientific, answer.

This obsession on the model-based folks part over increased resolution is 
something the rest of cladistics went through back in the late 1980s and early 
1990s. But people have to get to grips with the fact that sometimes the data 
are not decisive: sometimes we are honestly left with equally well-supported 
mutually exclusive alternatives. That is okay, that is how Science works.

The next step should be to gather new data (new taxa, new characters, 
reassessment of old taxa, reassessment of old characters, etc.) to refine the 
analysis.

Similarly, some people hold strict consensus trees in some holy esteem, instead 
of acknowledging that like different map projections, each consensus tree 
method has its positives and negatives but NONE contains all the information. 
Consensus trees are METAresults, not results. The results are the large number 
of output trees. There  are multiple ways to summarize the data, but a lot of 
people get confused and think that the strict consensus tree is actually the 
result of the analysis.

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216                        
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
http://www.geol.umd.edu/~tholtz/
Fax: 301-314-9661               

Faculty Director, Science & Global Change Program, College Park Scholars
http://www.geol.umd.edu/sgc
Fax: 301-314-9843

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        University of Maryland
                        College Park, MD 20742 USA