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Re: Our current understanding of Mesozoic bird phylogeny



the new Yixianornis paper (Clarke et al., 2006)

I have managed to miss that one. Which journal was it in?

Two characters of my own (median sternal process expanded distally;
mtIV longer than mtIII) that I thought might affect enantiornithine
relationships.

Yes, but the first looks ontogenetic to me. Or, more probably, _partially_ ontogenetic (there's probably a phylogenetic signal in when in ontogeny the sternum ossifies that far).


Caudal vertebral count was revised to be a total
count and not just of free vertebrae.

Good, but how did you count the vertebrae in the pygostyle?

Tree:

- *Wyleyia* as the basalmost enantiornithean is interesting.
- *Vorona* and *Elsornis* on the next node is also interesting.
- Is *Liaoxiornis* diagnostic when its ontogenetic age is taken into account?
- How did you code the ontogeny-dependent characters of *Iberomesornis* -- as "?"?


| |?-Jibeinia adult

Oho! What's that?

           |                    `--+--+--Yungavolucris
           |                       |  |--Hebeiornis
           |                       |  |--LP-4450-IEI
           |                       |  `--+--GMV 2158
           |                       |     `--GMV-2159

Curiouser and curiouser...

           |                       `--+--Gobipterygidae
           |                          |  |--Boluochia
           |                          |  `--Gobipteryx

Are they held together by anything else than their toothless pmx?

           |                          `--Avisauridae
           |                             |*-Avisaurinae
           |                             |  |--Avisaurus
           |                             |  `--Soroavisaurus
           |                             |--Sinornis
           |                             `--+--Liaoningornithinae
           |                                |  |--Eoalulavis
           |                                |  `--Liaoningornis
           |                                `--Concornithinae
           |                                   |--Concornis
           |                                   `--Neuquenornis

I like this very much! :-) Is there any chance that *Cuspirostrisornis* is in or next to this clade?


           `--Euornithes
              |--Aberratiodontus

I guess its many teeth pull it towards *Yanornis*?

`--Ornithuromorpha

So you're using the older definition that does not mention *Vorona* :-P

                       `--+--Apsaravis
                          `--Ornithurae sensu Chiappe
                             |--Hesperornithes
                             |  |--Baptornis
                             |  `--Hesperornis
                             `--+--Gansus
                                `--Carinatae
                                   |--Ichthyornis
                                   `--+*-Apatornis
                                      |--Limenavis
                                      `--+--Iaceornis
                                         `--Neornithes

How classical.

Highly unlikely
875 steps- Otogornis as a euornithine ambiortiform
This is Kurochkin's (1999) idea, based on his reinterpretation of the
material. Even if I were to grant Kurochkin's alternative morphology
(coracoid tubercle = procoracoid process), the tree would still be 873 steps
or so, showing Kurochkin's identifications for these are probably wrong.

Oh.

871 steps- Protopteryx and Longipteryx successively closer to Ornithothoraces
This kind of paraphyletic Enantiornithes was proposed by me back in 2001 on the DML, based on six characters, all of which were examined here. Notably, far more enantiornithine characters have been described in it now than were proposed by Zhang et al. (2001). I now officially reject this hypothesis.

Ah. Too bad. The 3rd-finger lengths fitted so well :-)

870 steps- Patagopteryx outside of Ornithothoraces
I've noticed several characters that are remarkably basal in Patagopteryx,
such as the unreduced proximal coracoid and brevis shelf, but apparently
these are near certainly reversals.

The coracoid shape is to be expected of a flightless maniraptoran, primarily or secondarily.


Not likely, but possible
[....]
867 steps- Gansus as a hesperornithine

This idea is in very bad company...

867 steps- Ambiortus as a palaeognath
This goes back to Kurochkin (1985), and was still entertained by him in 1999
at least.

Last time I looked, Feduccia still clung to it, but that may have been 1999, too.


Very possible
862 steps- confuciusornithids as enantiornithines
Surprisingly, this reduced version of Sauriurae (which shouldn't be termed
Sauriurae, as it lacks Archaeopteryx) is highly parsimonious. The addition
of Chiappe's characters makes it slightly less so than the traditional
(western) ornithothoracine view.

Surprisingly indeed!

Noguerornis' relationship is hard to pin down

I'm surprised you got that far with those fragments!

861 steps- Odontornithes

:-o

Just four more steps in addition to 857! Wow. Where does *Gansus* go in this case?

860 steps- Yanornis basal to Songlingornithidae + Ornithurae

Ah. I got that 4 years ago -- having a better description of *Yixianornis* than of *Yanornis* at my disposal.


860 steps- Apsaravis closer to Carinatae than Hesperornithes
This was suggested in the original description of Apsaravis (Norell and
Clarke, 2001), but found to be slightly less parsimonious by Clarke and
Norell (2002).  The change was due to correcting a few codings between
papers.

In sum, we need a lot more basal hesperornithean fossils, or the long branch of Hesperornithes will continue to attach itself to wherever it wants.


Does anything surprising occur in trees with 858 steps? :o)