Re: Coelurosaur analysis update

["Jaime A. Headden" <qilongia@yahoo.com>]

David Marjanovic (david.marjanovic@gmx.at) wrote:

<Wow!>

  Indeed ... see below.

<

>>|--Monolophosaurus
>>|--+--Sinraptor
>>|  `--Allosaurus
>>`--+--+--Bagaraatan
>>   |  `--Tyrannosauridae

<I'll blame the lack of coelurosaur synapomorphies for this... :-)>

  Without seeing the character support, and given this is a largely
cranial/pectoral/axial paper anyway, it is likely there are two things in
the jaw of *Bagaraatan* forcing this association: the first is the
antarticular shared in *Bagaraatan* and *Allosaurus*, providing a position
that in other matrices is never found, where the former is far closer to
birds than this. And the shape of the posterior jaw, which is
tyrannosaurian in aspect generally. That the form was found in the Nemegt,
and that nothing links the cranial to the postcranial, as the vertbrae
preserves start at the hip, I would like to voice a question on the
viability of the holotype as a whole as a whole animal. Nonethless, the
jaw itself, aside from the dentary, is largely tyrannosaurid anyway, from
the articular forward, a fact little commented upon by Osmólska (1996)
herself. So I'd wait for: 1) a complete matrix; 2) tests to affirm the
consistency of the cranial and postcranial material in *Bagaraatan*
itself. This would seem only prudent given the unusual position, though
not unlikely if it is a late surviving tyrannosauroid in the
end-Cretaceous. "Yes," said the man: "question everything."

<
 
>>                 |     `--+--+--Caudipteryx zoui
>>                 |        |  `--+--Nomingia
>>                 |        |     `--+--Caudipteryx sp. nov.
>>                 |        |        `--Avimimus
>>                 |        `--+--Incisivosaurus
>>                 |         [ `--other oviraptorosaurs ]
  
  Cooler still!>

  I would REALLY like to see the character support on this tree, though it
does not differ much fomr some earlier speculations onlist. For instance,
the sp. nov. of *Caudipteryx* refers to BMP 0001, otherwise considered a
specimen on *C. zoui*. *Nomingia* may be the more complete skeleton of
*Elmisaurus*, an idea I am sure has not occured to just myself. *Avimimus*
and *Caudipteryx* typically share few features, and possess quite a few
distinct structures in the arm, shoulder, hip, leg, and vertebrae, so this
is of great interest, I am sure. Of course, would love to see the matrix
completed, because this data would seem rather premature and misleading as
characters are added and the remainder of the material analyzed.

<

>>                         `--+--+--Scansoriopterygidae
>>                            |  `--+--Rahonavis
>>                            |     `--+--+--Archaeopteryx
>>                            |        |  `--Wellnhoferia
>>                            |        `--+--Shenzhouraptor
>>                            |           `--Jixiangornis

Yeahaah! Almost as if I'd constructed it! :-) Warning: including
*Yandangornis* and *Hulsanpes* could destroy it. -- Just strange that the
dromies are so far away...>

  I think the position of the scansoriopterygids has a lot to do with
this. And although I am not surprised that the long-tailed "birds"
*Shenzhouraptor* (inc. "Jeholornis") and *Jixiangornis* (which might as
well be a specimen of Shenzhou as far as I'm concerned, given the same
degree of variation distinguishes all specimens of the Shenzhou-Jeholo
complex as much as from Shenzhou and Jixiang) are where they are being
found in this, when the two (Jeholo and Shenzhou) were separate in other
updates they appeared to fall in different positions, so perhaps joining
them into a single OTU was premature. They may just as likely be separate
species or so forth of a single taxon, but perhaps worth retaining.

<<- enantiornithines as ornithuromorphs.>>

<Have you included the few enantiornithine and euenantiornithine
synapomorphies that I have still found?>

  I am more surprised that *Apsaravis* was not found as a carinate even
given the relatively limited matrix rendered here, or that the
"ornithuromorph" complex is so unresolved; the position would offer that
*Apsaravis* was an enantiornithine, which as far as I understand the pedal
and pectoral material is as likely as *Incisivosaurus* as a basal
tyrannosaur.

  Cheers,

=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

__________________________________
Do you Yahoo!?
Yahoo! SiteBuilder - Free, easy-to-use web site design software
http://sitebuilder.yahoo.com