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Re: PDF-request: Original description of Lagosuchus and/or Marasuchus
Mike,
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.
David
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
>