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Re: Archaeopteryx with bird book, was Re: Archaeopteryx flight

John Hunt (john.bass@ntlworld.com) wrote:

<This is all really cool stuff about _Archaeopteryx.  The fundamental questions
asked following its discovery still lack a definitive answer.  Is it an avian
dinosaur or a non-avian dinosaur with wings?>

Depends on your definition of "avian". _Aves_ has received at least
three phylogenetic definitions:
- _Aves_ sensu Ax consists of everything closer to modern birds than
to modern crocodylians.
- _Aves_ sensu Gauthier consists only of the crown clade of extant birds.
- _Aves_ sensu Chiappe lies in between: it is the last common ancestor
of _Archaeopteryx_ and modern birds, plus all descendants thereof.

_Archaeopteryx_ is an avian sensu Ax and sensu Chiappe (by
definition!), but not sensu Gauthier. It should be noted that Ax's
definition, which would include all dinosauromorphs and quite possibly
pterosauromorphs, is not exactly popular. Gauthier and de Queiroz
(2001) proposed the name _Panaves_ for such a clade.

Most researchers today probably use _Aves_ sensu Chiappe, although
_Aves_ sensu Gauthier is certainly not unused. Myself, I try to
specify which version I mean in each case where it matters (although
lately I've been favoring sensu Gauthier).

BUT, I suspect what you may really want to know is whether Archie's
wings are homologous with those of modern birds. They are.
Mike Keesey
The Dinosauricon: http://dino.lm.com
Parry & Carney: http://parryandcarney.com