On 5/4/07, Mike Taylor <firstname.lastname@example.org> wrote:
For whatever very little it might be worth, my own position is that
the "traditional" understanding of birds is that _Archaeopteryx_ is
the most primitive animal that is defined to be a bird; and so the
node-based definition of Chiappe best captures this notion, so that
Aves = (_Archaeopteryx_ + modern birds).
I think Marjanovic's proposed definition (see
traditional usage far better, since _Archaeopteryx_ has not always
been an essential member, but dromaeosaurids, troodontids, etc. have
generally been essential *non-members*.
Still, I prefer the crown group definition for reasons stated here:
(And also stated at more length by Gauthier and de Queiroz, 2001.)
As discussed on that forum (and years ago on this forum), perhaps it
would be wise to coin a new name, "Ornithes" (shockingly unused to
date), for one of the definitions.
But I know that lots of
people have other ideas, and I deliberately didn't adopt a position on
that question in the paper because I didn't want to get bogged down
in what is from my perspective a side-issue. (After all,
_Archaeopteryx_ weighed WAAAY less than ten tons.)