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