Re: Revising Hou et al, 96 (very very long)

["David Marjanovic" <david.marjanovic@gmx.at>]

----- Original Message -----
From: "Mickey Mortimer" <Mickey_Mortimer111@msn.com>
Sent: Wednesday, April 24, 2002 9:46 AM

> > <6. Elongate distal chevrons and prezygopophyses
> >   Also in Microraptor, which is even more bird-like (but still thought
to
> > be a deinonychosaur by many).>
> >
> >   Yes, and for many other reasons, including the pes construction (an
> > apparent troodontid + dromaeosaurid synapomorphy, along with pedal digit
> > II features).
>
> That are all also found in Rahonavis, a probable avialan.

Just OOC... suppose I came up with

+--Pygostylia
|--whatever
`--+--*Archaeopteryx*
   |--*Rahonavis*
   `--+--*Microraptor*
      `--+--*Sinornithosaurus*
         `--+--*Bambiraptor*
           `--Dromaeosauridae

What must I ignore to pretend that this is very easy to find if some
character polarities are set "the right way"?
        Several very birdlike features of *Rahonavis* must be convergent in
any case. Examples are the scapula-coracoid joint that confuciusornithids
don't have, the slow growth (like Enantiornithes and *Patagopteryx*) that
confuciusornithids don't have either, and the quill knobs that, it seems,
appear somewhere in Euornithes and disappear in tinamous and *Piksi* (free
pdf -- sample issue -- at www.nrc.ca/cisti/journals/sample/e01-057.pdf!!!)

> > <unserrated premaxillary teeth;>
> >
> >   Functional, irrelevant, and convergent with other taxa; perhaps diet
> > related.

And, in addition, perhaps plesiomorphic (also seen in compsognathids and
IIRC *Ornitholestes*).

> No data is irrelevent, most morphological synapomorphies are functional.
> I'm sure dental characters are diet-related.  You don't see people
doubting
> the D-sectioned teeth of tyrannosaurids, despite the fact they were
> convergent with Pelecanimimus, diet-related and functional.

As has been explained onlist, the exact shape of tyrannosauroid pmx teeth is
pretty unique.

> > <boomerang-shaped furcula;>
> >
> >   Not in *Sinornithosaurus*; its is rather shallow in aspect when viewed
> > from the "top/rostral".
>
> It's thinner than Archaeopteryx, but does have the same morphology.  Very
> different from Velociraptor.

Likewise, *Bambiraptor* has a boomerang-shaped one, and so do
oviraptorosaurs, no? The furcula seen in *Velociraptor*, with its straight
rami, is IMHO rather apomorphic anyway.

> > <fibula <20% of tibia width.>
> >
> >   Size related.
>
> Which is why Compsognathus lacks it..... we all know how huge it was.  ;-)

Erm... err... maybe functional, related to the secondarily rather short legs
of dromaeosaurids?

> >   other features that support the Deinonychosauria and the close
> > association of *Sinornithosaurus* to Dromaeosauridae:
> >
> >   1. pedal phalanx II-2 with elongation of the ventral edge of the
> > proximal articular facet, providing the dorsal extension of the ungual
> > phalanx.
>
> Like troodontids and Microraptor?

Why not? :-)

> >   2. pedal phalanx II-3 ungual forms raptorial claw.
>
> Like troodontids, Rahonavis and Microraptor?

Why not, see above? :-)

> >   3. elongate posterior flanges of the metatarsals II and IV, converge
or
> > nearly converge at the midlength.
>
> Like troodontids, Microraptor, Archaeopteryx and probably Rahonavis?

Same! :-) In the Ostrom Symposium Volume, Archie and Pygostylia share damn
few features, and all of those are pretty ambiguous. Actually I wonder why
Archie is still hailed as their closest relative by so many people. (Where
does it come out in DA, before I get that book?)