[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Dinosauricon Phylogeny: complete

T. Michael Keesey wrote-

> This is an interesting grouping.
> >           # *Achillobator*
> >           # *Adasaurus*
> >           # *Dromaeosaurus*
> >           # ? *Unenlagia*
> >           # *Utahraptor*

And one supported by few characters, none known in all members.
Achillobator, Dromaeosaurus and Adasaurus all have a stout pedal phalanx
II-2.  Achillobator shares double dorsal pleurocoels and some primitive
characters (presumedly reversals) with Utahraptor.  Unenlagia's ilium has a
few characters in common with Achillobator, but not Adasaurus.

> And then figure out where the non-type specimens go....
> (No generic name has ever been proposed for _bavarica_, right? Is it
> that it allies with one of the other three species to the exclusion of the
> other two?)

Elzanowski (2002) says neither the Maxberg or Harlaam spacimens can be
assigned to a species.  Personally, I'm doubtful as to the validity of A.
siemensii and A. bavarica.

Nick Gardner wrote-

> CMIIW, but doesn't the presence of more than 4 teeth still
> represent itself as possibly synapomorphic for Largirostrornis and
> Cuspirostrisornis?

Assuming Hou's correct about premaxillary tooth count, yes.

> Can you provide a reference for the original description of Nanantius and
> "N. valifanovi", as well as for the synomization of Gobipteryx with "N.
> valifanovi"?

Molnar, 1986. An enantiornithine bird from the Lower Cretaceous of
Queensland, Australia. Nature 322 736-738.

Kurochkin, E. N.  (1996) A New Enantiornithid of the Mongolian Late
Cretaceous, and a General Appraisal of the Infraclass Enantiornithes
Palaeontological Institute of the Russian Academy of Sciences, Moskou,
Special issue 60 pg.

Chiappe, Norell and Clark, 2001. A New Skull of Gobipteryx minuta (Aves:
Enantiornithes) from the Cretaceous of the Gobi Desert. American Museum
Novitates 3346 1-15.

David Marjanovic wrote-

> > - maxillary fenestra present (P)
> Unknown in *Iberomesornis*... and *I.* appears to be crucial for keeping
> *P.* and *L.* in Enantiornithes, because it's always more basal when
> any structure in that part of the tree.

No reason not to include the character.

> > - posteromedial sternal process absent (P)
> > - posteromedial sternal processes not pointed (L)
> > - broad posteromedian sternal process (P)
> Could be one character: sternum not particularly well ossified. Again hard
> to compare with *Iberomesornis*.

The first two perhaps, the third, no.  If anything, a narrow posteromedian
process would be less ossified.  Iberomesornis has such a narrow process,
but the condition of its posteromedial processes is unknown.

> They have an acrocoracoid?!? In my matrix, nothing else except *Anas* and
> *Ichthyornis* would have had that. Because I didn't know more about the
> distribution of this character, I ignored it. Looks like I really
> have...

Uh, of course they have an acrocoracoid.  It's just a modified coracoid
tubercle.  Most ornithothoracines have one.

> > - ventral position of a small, short and oval humeral articular head.
> Oval? Like globose, as opposed to "cranially concave and caudally convex"?

No, I think the shape is in anterior view, not proximal view.

> > - long and thin manual digit II-2.
> IMHO *Otogornis* only preserves digit I.


Tim Williams wrote-

> * The inclusion of _nomina dubia_ (e.g., _Palaeoscincus_, _Pteropelyx_,
> _Agathaumas_) is probably just a waste of space, and giving them equal
> billing to the valid genera gives them the illusion of legitimacy.  Most
> based on teeth or scrappy postcranial material, and named at a time when
> was routine to give a new name to teeth and scrappy material.

As Mike said, nomen dubium is a largely subjective designation.  Even teeth
might be diagnostic once studied in depth.  Smith's (2002) unpublished
dissertation is a great start.

> I had thought _Minmi_ lay outside the nodosaurid-ankylosaurid dichotomy;
> I may be thinking of an old phylogeny.  _Struthiosaurus_, I thought, was
> inside the Nodosauridae.

For Minmi- not according to Hill et al. (2003), the most comprehensive
ankylosaurian phylogenetic analysis to date.
For Struthiosaurus- not according to Vickaryous et al. (2001), the most
extensive phylogenetic analysis including the taxon.

> I don't  believe _Avaceratops_ is a centrosaurine; it appears to be
> the Centrosaurinae-Chasmosaurinae dichotomy.

Forster (2002) disagrees.

Mickey Mortimer