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Re: PDF-request: Original description of Lagosuchus and/or Marasuchus


I appreciate your thoughts, but you're adding factors and suppositions not 
mentioned in Dr. Parker's original comments. 

You're also ignoring the key component in my comment: a priori taxon inclusion 
sets that are way too small for the gamut being tested in recent studies.


On Apr 10, 2010, at 10:56 AM, Mike Habib wrote:

> On Apr 10, 2010, at 5:56 AM, David Peters wrote:
>> To your point, if simply coding from the literature won't work this time it 
>> means the literature is not only wrong, it's >so< wrong that topology 
>> tumbles. And now is a good time to remind ourselves that the literature was 
>> written from >first hand observation<.
>> So, what is your logic leaving us with? If first hand observation won't work 
>> (see above), plane tickets would be a waste of money. Right? Yes, it's a 
>> vicious unwinnable Catch-22 you are creating here.
> Not quite.  Bill Parker was indicating that coding from the literature is, 
> itself, the step of insufficiency.  The literature was written from first 
> hand observation, but writing based on that literature is no longer first 
> hand observation.  The best way to re-evaluate former first hand observation 
> is to make new first hand observations of our own - that is, go see the 
> specimens for ourselves.
> The literature is important, of course, and it is completely sensible to rely 
> on it for many types of information.  However, when coding a phylogenetic 
> reconstruction, using the literature can be tricky business.  Some methods do 
> this exclusively of course (supertrees and supermatrices, for example) but 
> these methods often have goals other than supplying a novel, robust topology 
> (supertrees, for example, are mostly a method for quantifying the historical 
> record of published phylogenies up to that time, often as a way of evaluating 
> consensus in the literature.  This is a different goal than trying to 
> actually reconstruct ancestry).
> It is also worth pointing out that some methods of coding from the literature 
> are more robust than others.  For example, if one is simply adopting the data 
> matrix supplied by another author, and combining it with others 
> (supermatrix), then you are only assuming that the prior authors were 
> accurate.  This has its own set of problems, but can be workable in some 
> cases.  However, trying to create new codings from the literature (say, for 
> example, by trying to code from a photograph or other second-hand source) is 
> exceptionally difficult to do accurately, and there will almost always be 
> features that are not accurately represented in a 2D photo or other such 
> representation.  I believe this is what Parker was suggesting should be the 
> impetus to travel and observe specimens directly.
> Cheers,
> --Mike
> Michael Habib
> Assistant Professor of Biology
> Chatham University
> Woodland Road, Pittsburgh PA  15232
> Buhl Hall, Room 226A
> mhabib@chatham.edu
> (443) 280-0181