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Re: Tyrannosauroids and dromaeosaurs
David Marjanovic wrote-
> Oh, wow.
Yeah. I just added Anserimimus (codable for 24 characters), and it changed
the topology a bit. Oddly, it's most parsimoniously next to Compsognathus.
> > I also changed several cranial and
> > cervical characters to be MUCH less subjective.
> How? (Or would that take too long to write down?)
Some of the alterations I remember...
I changed the "double-headed quadrate" character into two characters-
"quadrate contacts squamosal and prootic or opisthotic" and "proximal heads
of quadrate widely separated". Did you know troodontids have the former? I
wonder why Maryanska and Osmolska (1997) made such a big deal about
caenagnathoids having it.
I deleted the "quadrate not sutured to quadratojugal" character because it
ends up having identical distribution to "lateral cotyla in quadrate for
quadratojugal", but with a lot more ?'s. Some taxa with disarticulated
quadratojugals might have it, but not a cotyla, but how would we know?
I added a "dentary anterior to emf short compared to mandibular height above
emf" character, which combines Microvenator and oviraptorids in Makovicky
and Sues (1998).
I had Elzanowski's (1999) "intramandibular joint reduced" character, but
revised it to reflect the actual proximity of the splenial and prearticular
edges (as mentioned by Hurum 2001), which is directly observable. I then
combined this with Currie's "widely open internal mandibular fenestra"
I deleted the "two pairs of pleurocoels in cervical centra" character
because O'Connor (2003) found it to be extremely variable within species and
individuals of modern birds, and it seems to be so in coelurosaurs too.
> > `--+--+--Iliosuchus
> > | |--Fukuiraptor
> > | |--Stokesosaurus
> > | `--+--Bagaraatan
> > | |--Aviatyrannis
> > | `--Tyrannosauridae
> *I.* immediately a tyrannosaur -- cool. But *Fukuiraptor* and not
Well, now I get-
|--Carnosauria (inc. Sinraptor, Allosaurus, Monolophosaurus)
| `--+--"Chilantaisaurus" maortuensis
Anserimimus fixed it. :-)
> > `--+--+--Proceratosaurus
> > | `--+--Coelurus
> > | `--+--Scipionyx
> > | `--YPM 1996
> Wasn't YPM 1996 thought to be an "enigmosaur"? Or have I confused the
> %$%$%§$§ numbers?
Yeah, it was. I think I've included all the relevent characters noted by
Frankfurt and Chiappe too....
> > `--+--Yixianosaurus
> > `--+--+--+--Caudipteryx zoui
> > | | `--Caudipteryx sp.
> > | `--+--+--Incisivosaurus
> > | | `--Avimimus
> Does *Yixianosaurus* destroy the "enigmosaurs", or is this more
> How come *Caudipteryx* is more basal than *Incisivosaurus*? And what does
> the latter share with *Avimimus*?
Nah, segnosaurs are just drawn more basally quite often. Sometimes as
arctometatarsalians. Now Enigmosauria exists again, though Beipiaosaurus
and Erliansaurus form a clade in the basal Coelurosauria and Therizinosaurus
is directly basal to avepectorans. Stupid segnosaurs, it's so hard keeping
them together. Damn the ghost of Ken Kinman! ;-)
As for why avimimids are more derived than Caudipteryx-
- subnarial process of premaxilla contacts nasal (unknown in Avimimus).
- nasal recesses (unknown in Avimimus).
- palate mostly ventral to maxilla and jugal (unknown in Avimimus).
- prominent coronoid eminence on surangular.
- surangular foramen absent.
- retroarticular process elongate.
- at least six sacral vertebrae (unknown in Incisivosaurus).
I also noticed the plesiomorphic triangular splenial has been transformed in
Incisivosaurus, caenagnathids and oviraptorids, but not Caudipteryx. But
this character isn't included yet.
And Avimimidae is supported by-
- premaxillae fused anteriorly.
- paraquadrate foramen absent.
> > `--+--Protarchaeopteryx
Now it's a basal enigmosaur, sister to Segnosauria + Oviraptorosauria.
> > `--+--+--Archaeornithoides
> > | `--+--Byronosaurus
> > | `--+--Pyroraptor
> > | `--+--Sinovenator
> *S.* so high up? Interesting... well, actually, the troodontid topology is
> pretty standard.
More like Byronosaurus so low.
> > `--+--Scansoriopterygidae
> > `--+--+--Archaeopteryx
> > | `--Wellnhoferia
> > `--Eumaniraptora
> What are the synapomorphies of Eumaniraptora?
We'll never know, because now everything's back to normal in that area,
except that troodontids are avialan. I hope this post shows the importance
of including all relevent taxa in an analysis.
> > |--+--+--Microraptor gui
> > | | `--+--Microraptor zhaoianus
> > | | `--Cryptovolans
> Why not *M. gui* and *C.* as sistergroups?
- sternum length (anterior median tip to posterior median tip) width
(narrowest width across costal margins, or greatest width for those taxa
without costal margins) ratio > 170.
- proximal height of manual ungual I <160% of manual ungual II .
- ratio of manual phalanx I-1 and metacarpal I >225.
- ratio between manual phalanx III-2 and III-1 < 50.
> > | `--+--Saurornitholestes
> > | `--+--IGM 100/1015
> > | `--+--+--Achillobator
> > | | `--+--Utahraptor
> > | | `--Velociraptor
> > | `--+--Deinonychus
> > | |--Dromaeosaurus
> > | `--Adasaurus
> > `--+--Unenlagia
New 90% majority rule-
| `--NGMC 91
> > `--+--+--Noguerornis
> > | |--Boluochia
> > | |--Neuquenornis
> > | |--Gobipteryx
> > | `--Enantiornis
> How did you get the position of *Boluochia* so well resolved?
I coded it. :-) For 16 characters. Is a polytomy with four other taxa
really well resolved?
> > |--+--Ambiortus
> > | `--Apsaravis
> How come?
- hypapophyses on anterior dorsal vertebrae less than 25% of posterior
centrum face height.
- ventral tubercle of humerus not separated from humeral head by deep
capital incision on caudal surface.
> > |--+--Patagopteryx
> > | `--+--Liaoningornis
> > | `--Songlingornis
My analysis doesn't like having Patagopteryx as the most basal
ornithuromorph. Or Songlingornis as a yanornithid. Or yanornithids being
monophyletic at all. But I have yet to include most relevent characters.
> > - Pelecanimimus is a deinocheirid.
> That group leads me to suspect you might have got some polarities wrong.
> (Or... of course... everyone else.)
Eh, much like the Incisivosaurus vs. Caudipteryx situation, I think people
see a trend they like and arrange taxa on that (rather Olshevskian). They
think everything has to be developing towards ornithomimids. So they judge
a taxon's placement based on tooth reduction and manual digit I elongation.