Re: Class AVES expanded (preliminary classification)

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

>       The fact that Archaeopteryx was so long considered the first bird
was
> just an accident of history, but new fossils (from China in particular)
now
> almost cry out for a paradigm shift that is reflected in our nomenclature,
> both formal and informal.

I agree.

>      The precise synapomorphy (or group of synapomorphies) is not yet
> certain, but it will involve elements of the "folded" forelimb
(particularly
> in the wrist and manus).  I am certainly open to suggestions on which
would
> be the best and most precise synapomorphies for this new definition of
Class
> Aves.

Big semilunate carpal: apparently a synapomorphy of *Ornitholestes*, birds
and everything in between (whatever that is). Is that an idea?

>      This expanded Aves will now include (but not be defined by) forms
that:
> (1) possess vaned feathers;

This way it might steadily expanded with an improving fossil record. Suppose
we find something like *Ornitholestes* or *Nedcolbertia* in Liaoning, or an
ancestral tyrannosaur, and it has wings... under some phylogenies such
discoveries would bloat your Aves a lot.
[Just for the record -- I don't know of any rumors of any such fossil, no
need to wait for a paper AFAIK :-) ]

> (2) possess eggs with ornithoid microstructure;

Unknown for many clades. It's also unknown just how ornithoid or not the
dinosauroid-prismatic eggs of troodontids and the dinosauroid-spherulitic
eggs of ?segnosaurs are.

> (3) possess lateral shoulder joints;

Known with certainty for *Archaeopteryx* and (other?) deinonychosaurs.

> (4) enlargement of sterna;

Rarely known in fossils. BTW, *Pelicanimimus* has very big sterna.

> and various
> other bird characteristics.

Such as?

>      Furthermore, it will now contain those forms which display various
> degrees of pubic retroversion (including mesopuby).

Such as *Allosaurus* and *Herrerasaurus*? :-/

> Many of these forms
> have pelvic structures that are more bird-like, and they should probably
> never have been classified in Saurischia in the first place.

That's because the name refers to a plesiomorphy :-)

> I believe the
> time has come to expand Class Aves to include all these "birds".

It might extend right into the middle of the basal coelurosaur mess. Maybe
you should look for a better known part of the tree.

> I had already classified Order Mononykiformes [...]

Why not Alvarezsauria (an existing name, AFAIK Novas, 1991)
respectively -formes?

> 1  Segnosauriformes
>         1  Pl. Beipiaosaurus
>         2  Alxasauridae
>         ?  Pl. Neimongosaurus
>         3  Therizinosauridae

Why not Pl. *Alxasaurus*, too? Only because Alxasauridae is named?

> 2  Caenagnathiformes

Why not Oviraptorosauria/-formes? Why 2 and not B (why no "Enigmosauria")?

>         1  Pl. Protarcheopteryx
>         ?  Avimimidae

This implies the positions of *Neimongosaurus* and Avimimidae are equally
(un)certain. Do you think that's the case?

> [...]
> 3  Plesion Alvarezsaurus
> B  Mononykiformes
>         1  Patagonykidae
>         2  Parvicursoridae
>         3  Mononykidae

I suggest

2 Alvarezsauria
        1 Pl. *A.*
        2 Pl. *Patagonykus* (you'd have to name P.idae as fam. nov.)
        3 Parvicursorinae = Mononykinae

Parvicursorinae was named as a subfamily (of Alvarezsauridae) that includes
*Parvicursor* and *Mononykus*. Mononykinae was (later) named as a clade that
includes the most recent common ancestor of *P.*, *M.* and *Shuvuuia* and
all its descendants. Coding them as separate clades is IMHO impossible.

> 5  Archaeopterygiformes

Delete 8 -- 12, and you get my (2000) usage of that name :-)

>         1  "utahraptorid" family
>         2  Pl. Pyroraptor

An _extra_ clade for that poor poorly known *Pyroraptor*?

>         B  Velociraptoridae
>         C  Dromaeosauridae

Why not just B Dromaeosauridae, including both?

>         7  Archaeopterygidae

Monotypic. Why not a plesion?

>         8  Yandangornithidae

Monotypic. Why not a plesion?

>         9  Pl. Sapeornis
>        10  Confuciusornithidae

11 Pl. *Protopteryx*
12 Pl. *Longipteryx*
13 Pl. *Jibeinia*

>        11  Enantiornithidae

What! The entire diversity of Enantiornithes into just one family, but
Velociraptorinae and Dromaeosaurinae into extra families at the same time!
*Sinornis*... *Boluochia*... *Enantiornis*... *Gurilynia*... *Avisaurus*...
you want to stuff these all together while keeping V. and D. separate at the
same level? I mean, in the Mesozoic Enantiornithes had a bigger (known)
diversity than Euornithes!
        Phylogenetic taxonomy is so comfortable... all problems of that sort
evaporate... <poof> :-)

>        12  {{Euornithes}} (Patago., etc.)

Plesia for *Yanornis*, *Yixianornis*, *Liaoningornis*... at the base.

> And also note
> that I plan to add Plesion Bagaraatan once I decide the best place for it.

That's going to be a hard job.