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Re: Class AVES expanded (preliminary classification)
David Marjanovic wrote-
> > Isn't the largest stem-based avian clade already named Ornithosuchia?
> Bad name. Won't stay under PhyloCode anyway.
Fine, just use Avemetatarsalia, also already published and defined as that
> > Liaoningornis shows no evidence of being a euornithine, contra what is
> > "common knowledge". Just read the paper.
> Ref, please :-)
Hou, 1997. A Carinate Bird from the Upper Jurassic of Western Liaoning,
China. Chinese Science Bulletin 42(5): 413-417.
I've honestly no idea why this thing has always been said to be a basal
euornithine (well actually, the Feducciaries advocating it refuse to get
with the times, keeping a stem-based Ornithurae to put it in). Maybe they
need euornithines existing in the "Jurassic" to fuel their highly
unparsimonious Sauriurae-Ornithurae split "hypothesis". Reading Hou 1997
shows that it's an "ornithurine" because it has-
- keeled sternum
Like Neuquenornis, Concornis, Boluochia, Eoenantiornis, Protopteryx,
Longipteryx, some Confuciusornis specimens, etc.. The extent of the keel
varies (most have it only posteriorly), but Neuquenornis has a very well
developed keel extending anteriorly too.
- coracoid facets on anterior sternum
Oh, like Sinornithosaurus, Velociraptor and Bambiraptor?
- presternum articulated to anterior sternum
Uh, yeah.... the crack in the matrix making it appear to be two bones (as
Hou himself admits is possible). Ever seen a Mesozoic bird with a
"presternum"? Does any living bird have such a thing?
- internal and external cotlya of ulna developed
"Developed", eh? If he means present, Confuciusornis has these too for
example. If not, the character is too vague for comment.
- femoral head developed, with capital ligament fossa
Also seen in Avimimus, Velociraptor, Confuciusornis, etc..
So yeah, real great evidence there. ;-) On the other hand, the following
enantiornithine-like characters (including plesiomorphies, note
Enantiornithes is probably paraphyletic) are present-
- sternum greatly expanded posteriorly, with no lateral processes (like
- external condyle projects much frther than internal condyle on distal
humerus (like Enantiornis, Kizylkumavis, Alexornis)
- laterally convex distal coracoid (like Enantiornis, Concornis, etc.)
- elongate hypocleidium (like Concornis, Cathayornis, Protopteryx, etc.)
- narrow intercondylar groove on distal tibiotarsus
- tarsometatarsus only fused proximally (like Confuciusornis, Avisaurus,
> > Songlingornis, Yanornis and the
> > Archaeoraptor [...] [front] end all are _very_ similar though....
> Do you mean possibly synonymous?
Maybe. I haven't compared them in depth, but look at the sterna and skulls
of all of them. Chaoyangia may also be involved.