From: "Jaime A. Headden" <qilongia@yahoo.com>
To: dinosaur@usc.edu
CC: kinman@hotmail.com, dinogeorge@aol.com
Subject: Re: synapomorphies not "being" equal
Date: Mon, 3 Sep 2001 03:10:28 -0700 (PDT)
Ken Kinman (kinman@hotmail.com) wrote:
For one thing, synapomorphies are not created, they are observed. There
_are_ features that
unite two forms on a morphological paradigm, these being synapomorphies. I
do recall that you are
a neontologist and appear to be more familiar with genetic paradigms rather
than morphological
ones. Morphology does give us a different framework to operate in.
<I've been thinking very hard about this, and I am still not convinced that
all synapomorphies are
created equal. Some are "stronger" than others no matter how long or big
the evolutionary gap
happens to be in which it falls.
In my opinion, the one synapomorphy of Mammalia, the movement of the
three ossicles from the
mandible into the ear of the first mammals, was strongly selected for and
occurred relatively
rapidly. It is thus a very strong synapomorphy.>
Yes, it is a significant synapomoprhy. However, there are more than one
synapomorphy for
Mammlia, but this depends on what group you call Mammalia. If you are
referring to all eucynodonts
with three middle ear ossicles, then this is a broad category indeed, and
would include a good
deal of fossils (*Prokennalestes*, *Kuhneotherium*, etc..). However, as you
note, you'd rather not
have
<This almost cries out for the need for these purported synapomorphies to
be evaluated, and that
the strongest be identified and carefully scrutinized. The
therapsid-to-mammal transition is just
as well documented (if not more so) as that of the transition to
"non-dinosaurs" to dinosaurs.
Therefore the lack of a strong synapomorphy in the latter should be taken
as a strong signal that
a comprehensive reevaluation is required. The question is who will be the
"Dave Peters" of
dinosaur origins.>
So far, Paul Sereno, whose work has been somewhat in part revisionary of
dinosaur
interrelationships and (especially with Novas) the origin of Dinosauria.
Novas has been working on
dinosaur origins after Gauthier and before Sereno was, and came to the same
conclusions as did
Gauthier, and Bakker and Galton back in 1985 (before Gauthier's findings
were published). Or are
you trying to find someone to realize your hypothesis of a paraphyletic
Dinosauria?
<I believe than Crurotarsi will probably not survive, and it is still a
toss-up whether Dinosauria
will survive as a clade. Therefore those who have challenged me to come up
with an alternative set
of synapomorphies will have to wait for me to catch up or hope that those
that those who need less
"catching-up" will rise to the challenge. I would prefer the latter, since
I have other projects
that need attention, and strongly suspect that at least one of them will
will rise to this
challenge. All I can say is the sooner the better.>
Then you enter this game with loaded dice, Ken. Saying something to the
equivalent of "Crurotarsi
doesn't look real to me, it must be bad." This is not science.
=====
Jaime A. Headden
Aaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhr-gen-ti-na
Where the Wind Comes Sweeping Down the Pampas!!!!
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