Re: New alvarezsaurid

["Jaime Headden" <jaemei@hotmail.com>]

<1) Neornithes is included inside the Ornithurae.>

My mistake.

<3) Regardless of the enantiornithines position systematically, they 
are birds. Cathayornis shows many bird-like features in the skull : 
enlarged fromtal, supraoccipital butted against parietal, reduced 
parietal, ventrally positioned foramen magnum, and an orbital recess on 
the quadrate. Cathayornis is a typical enantiornithine so these features 
are valid for the whole group. All enantiornithines have a pygostyle, 
sternal carina, carpometacarpus, heart-shaped ulnarae, strut-like 
coracoid, etc.>

*Cathayornis* was refered to this group. Only the type of the group 
(*Enantiornis*) can be used to formulate a systema for all others, not 
something added in later that---while having a whole bunch of characters 
that resemble those seen in various other referred birds, but none have 
the same number of characters (or at least, known)---and thus 
conclusions with "are" and "aren't" can be a little premature. Oh, I'm 
not saying enantiornithines are not birds, I'm just using them as a 
possible example of convergence, which is what this whole thing is 
really all about.

<Wrong. Though the oviraptor quadrate is birdlike, it is not 
streptostylic and the bar is mainly that of the quadratojugal.>

Derived characters on the bird's part. These are derived animals, don't 
forget, as compared to theropods in the classic sense (before many of 
these new-fangled birds poked their skulls out of the limestone).

<The oviraptor tarsometatarus exhibits no fusion too.>

Oviraptorosaur. I include *Elmisaurus* and *Chirostenotes*, whose 
tarsometatarsus is fused along the entire proximal length; derived 
character that could be reached would be entire tmt fused.

<Hesperornis definitely came from flying ancestors. The most basal 
hesperornithiform, Pasquiaornis, has a shoulder like that of a volant 
bird.>

I didn't say he didn't. In fact, in this, I agree with both you and 
George: these birds popped in from volant ansectors (previous step: they 
popped in from cursorial ones; equivocal, at the moment).

<Avimimids are chimeras.>

I was pretty sure of this when I first heard of it, some time ago, but I 
couldn't resist drawing Avi as all those specimens recontructed him. May 
I ask which are referred to what? I know the pelvis is theropod, the 
carpometacarpus is avian, and the skull...well, that has theropod 
attributes _and_ avian ones. Incidentally, much of my theories with Avi 
and Ovi concentrate on the pelvis and skull, so I would like to know the 
present view on what belonged to who, so I can correct my illustrations 
and notes before I've truly sunk myself without a lifevest on.

<<Flight is not a prerequisite bird character, so ratites are birds, and 
so is the penguin group. Ornithurines are birds, though they have 
teeth, and enantiornithines are birds, even though they have the 
reversed-ankle system. _Lacking_ a certain character does not occlude it 
from this clade. And protobirds, not birds, would be my reference.>>

<Lacking many, many, many, many, many, many, avain characters 
excludes them from Aves.>

Granted, yet Aves is highly derived from the condition of, say, 
*Deinonychus* and even *Archaeopteryx*, who lack many, many, many, many 
avian characters as well.

<The evidence is still misinterpreted. What you are viewing as valid 
characters are demonstratebly convergences when you look at the avian 
family tree.>

_Birds_ demostrate convergences to the point of icredulity among 
themselves, so much that we can hardly tell one fossil in a Holocene 
rock from a livinf descendang or relative (the answer's not in yet on 
*Diatryma* or *Titanis*, so....).

<Chickens still do fly for short distances. Anyway a paedomorphic 
change is associated with the loss of flight and this includes loss of a 
carina.>

And they are such ridiculous flyers that woodcocks with short little 
keels appear like lightning bolts in comparison.

<<<Enantiornithines have a carina, though it is in a posterior position 
as opposed to the ornithurine anterior. The similiarity of the 
scapulacoracoid in oviraptorosaurs and alvarezsaurs is actually just a 
similiarity that is brought on by the flightless nature of alvarezsaurs 
( compare a Diatryma scapulacoracoid to a Tyrannosaurus and see the 
convergence ). Aves is clearly a natural group.>>>

<<Yes, it is. But which groups get to stay in it, and which not?>>

<Alvarezsaurs stay in because they have many avian characteristics that 
oviraptorosaurs lack.>

Unless, if future evidence supports it, alvarezsaurids are shown to be 
derived divergently from the most recent common ancestor of the two 
closer to them than, say, dromies and Archie. There are two groups in my 
mind that may have led to birds as we think of them: Archie's, and 
Ovi's. Which gets the acclaim, and which doesn't, really is up to future 
research or a single fossil that puts everything together, possibly in a 
way we didn't expect.

Jaime A. Headden
Qilongia

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