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Just Jixiangornis (was Re: Iguanodon(?) sp. and Jixiangornis)



Mickey Mortimer wrote-

A very strange skull. Reminds me of Caudipteryx, with the unbird-like
rounded premaxilla. Funny how all these oviraptorosaur-like basal birds are
showing up now (Shenzhouraptor, Omnivoropteryx), alongside the
dromaeosaur-like ones. The skull is seems to resemble nemegtosaurs in the
orbit's position and shape, and laterotemporal fenestra extending anteriorly
below the orbit. The antorbital fenestra is also shown extending below the
orbit, with a large maxillary fenestra anteriorly. Nasals are short, as
expected, but the narial region is obscure. No less than three possible
narial openings are present, and the configuration of bones around them is
uncertain. The naris seems not to be above the maxillary fenestra, unlike
oviraptorosaurs, if everything here is properly identified and articulated.
The orbit is really much too small for a maniraptoriform and located far too
high up. There is a supposed jugal wrapping caudally around the antorbital
fenestra and possessing a prominent dorsal process that would make part of a
complete postorbital bar. Now, I think the skull is misinterpreted. The
orbit and antorbital fenestra are probably both part of a larger crushed
orbit. The maxillary fenestra would then be the real antorbital fenestra,
and the jugal would be a palatal bone (ectopterygoid and/or pterygoid).



Someone needs to try and create a reconstruction from the plates. I made a life reconstruction when the colored, low-res version was first available, but it looks pretty stupid now with its box like main skull that has a sudden dip for the front of the snout.



No hypocleideum on the furcula, but a surprisingly small interclavicular
angle.  Coracoids are more strut-like than Jeholornis, being comparable to
Eoenantiornis (not convex laterally though).

Funny in a way considering how Czerkas et al. were very eager to make comparisons between _Omnivoropteryx_ and _Eoenantiornis_. What is _Eoenantiornis_? An enantiornithine or some basal bird outside of the Ornithothoraces?



The first digit is subequal mcII, like Omnivoropteryx and Sapeornis.
Phalanx II-1 is slightly longer than II-2 (22.7 mm vs. 21.1).  Metacarpal
III actually reaches slightly past metacarpal II.  Digit III seems very
reduced in width, with a tiny ungual.


The digit is very short provided the absence of the other phalanges is the true state and not an artifact of preservation.


The hallux is also disarticulated from the metatarsal, making the
retroversion suspect.


That observation was from the drawing, I had difficulty seeing much of anything in the plates, and at least it appeared... retroverted. Maybe it's time to use "zoom" in MS Photo Editor or Photoshop...


At least Orthavialae will be a useful term for the clade containing
Rahonavis, Shenzhouraptor (=Jeholornis), Yandangornis, Jixiangornis,
Sapeornis, Omnivoropteryx and Pygostylia.  Euavialae might just contain the
last five.  I'd place Jixiangornis in the Yandangornithidae pending a
phylogenetic analysis.


So... you're suggesting....

--Orthavialae
   |--Rahonavis
   |--Shenzhouraptor
   `-- Euavialae
       |--Yandangornithidae
       |    |--Jixiangornis
       |    `--Yandangornis
       |--Sapeornis
       |--Omnivoropteryx
       `--Pygostylia

What would support Orthavialae, Euavialae, and Yandangornithidae? Presumedly all forelimb and pectoral characters? _Sapeornis_ does have a pygostyle, so it might be closer to Pygostylia than originally believed. Does _Omnivoropteryx_ have a pygostyle?


Nick Gardner

Mickey Mortimer
-- Mickey Mortimer <Mickey_Mortimer111@msn.com> wrote:

A very strange skull. Reminds me of Caudipteryx, with the unbird-like
rounded premaxilla. Funny how all these oviraptorosaur-like basal birds are
showing up now (Shenzhouraptor, Omnivoropteryx), alongside the
dromaeosaur-like ones.

Could it be an indication of diet/behavior? I.e., could non-ornithothoracean
maniraptors with an "oviraptorosaurian aspect" be herbivorous/omnivorous, while
those with the "dromaeosaurid aspect" are carnivorous/insectivorous?


At least Orthavialae will be a useful term for the clade containing
Rahonavis, Shenzhouraptor (=Jeholornis), Yandangornis, Jixiangornis,
Sapeornis, Omnivoropteryx and Pygostylia.  Euavialae might just contain the
last five.  I'd place Jixiangornis in the Yandangornithidae pending a
phylogenetic analysis.

Were either of these new names explicitly defined?

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