Re: Postorbital processes (& weighting??)

["David Marjanovic" <David.Marjanovic@gmx.at>]

> >       Need to get some things cleared up here.  {Sinornis + Passer} =
> > Euornithes (not Ornithothoraces).
>
> Nope. Euornithes Sereno 1998 is {Neornithes > *Sinornis*}, while
> Enantiornithes sensu Sereno 1998 is {*Sinornis* > Neornithes}. He writes
the
> position of *S.* is so well known that he uses it rather than
*Enantiornis*,
> or something like that.
>
> >       Ornithothoraces is presently defined as {Iberomesornis + Passer}.
>
> True, sorry. But probably Sereno uses *Sinornis* instead, haven't checked,
> and at present that's the same clade.

Meanwhile I have checked.
Paul C. Sereno: A rationale for phylogenetic definitions, with application
to the higher-level taxonomy of Dinosauria, N. Jb. Geol. Paläont. Abh. 210
(1), 41 -- 83 (October 1998)
>From p. 65:

Aves LINNE [sic] 1758                                {*Archaeopteryx* +
Neornithes}
  *Archaeopteryx* MEYER 1861                {*A. lithographica* >
Neornithes}
  Ornithurae HAECKEL 1866                        {Neornithes >
*Archaeopteryx*}
    Ornithothoraces CHIAPPE & CALVO 1994 {*Sinornis* + Neornithes}
      Enantiornithes WALKER 1981                {*Sinornis* > Neornithes}
      Euornithes new taxon                                {Neornithes >
*Sinornis*}

>From p. 76:

"I have defined Aves in the traditional sense, recognizing a tradition-based
NST [node-stem triplet] to anchor the definition (Aves = *Archaeopteryx* +
Ornithurae) [...]. In this formulation, Ornithurae is a stem-based taxon, as
proposed in its initial phylogenetic definition (GAUTHIER 1986) [...].
    A diversity- and morphology-based NST is established for the principal
dichotomy among Mesozoic avians, the divergence of Enantiornithes ("opposite
birds") from Euornithes ("true birds"), a taxon coined here ([...] Table 4).
The three taxa composing this NST (Ornithothoraces = Enantiornithes +
Euornithes) are very distinct morphologically [as long as you stay outside
Liaoning?], as shown by long lists of synapomorphies (CHIAPPE 1996, SERENO
in review [a, b, or both?]). *Iberomesornis* served as a reference taxon in
the original definition of Ornithothoraces (initially referenced as the "Las
Hoyas bird" for a taxon initially named "Ornithopectae"; CHIAPPE 1991).
*Sinornis*, rather than *Iberomesornis*, is used here as a reference taxon
for Ornithothoraces, because the phylogenetic interpretation of *Sinornis*
is not in dispute; *Sinornis* is a member of Enantiornithes and is known
from many specimens [hear, hear]. *Iberomesornis*, on the other hand, has
been regarded either as a basal avian outside Enantiornithes (CHIAPPE 1996)
or as an enantiornithine (KUROCHKIN 1996, SERENO in review a), and the
single partial skeleton may not be complete enough to reach consensus
[meanwhile Sereno has published a paper that shows *I.* is in
Enantiornithes]. Ornithothoraces, defined here by the reference taxa
*Sinornis* and Neornithes [...], identifies the major dichotomy in avian
diversity during the Mesozoic."

"Sereno in review a": *Sinornis santensis* (Aves: Enantiornithes) from the
Early Cretaceous of northeastern China, in: L. M. Chiappe & L. M. Witmer
(eds): Mesozoic Birds: Over the Heads of Dinosaurs, University of California
"Sereno in review b": Definitions in phylogenetic taxonomy: Critique and
rationale. Syst. Biol.