Re: Rauhut's Thesis

["Mickey Mortimer" <Mickey_Mortimer11@msn.com>]

David Marjanovic wrote-

> So a Sereno like Deinonychosauria is supported here.
>
> :-o

Yes, but the evidence isn't very good in my opinion-
- splenial foramen open anteroventrally.  This is fine, but the only other
maniraptorans with splenials illustrated are therizinosaurids, oviraptorids
and Archaeopteryx.
- serrated premaxillary teeth.  Sinornithosaurus lacks this character,
although Rauhut includes it in the Dromaeosauridae.  So does the troodontid
Byronosaurus.  The presence of serrations in the basal maniraptoran
Protarchaeopteryx may have affected this character were that taxon included.
- axial epipophyses overhanging postzygopophyses.  True, though unknown in
most eumaniraptorans.
- axial neural spine reduced and rod-like.  Same as above.
- epipophyses of cervical vertebrae overhanging postzygopophyses.  Same as
above.
- pedal digit II much shorter than subequal digits III and IV.  I have yet
to examine this character in depth, but it seems more complex than it
sounds.  Digit II is usually shorter than IV to varying degrees in most
theropods, but is especially so in those with sickle claws.  I will have to
measure the ratios of II/IV in various theropods, but note that the avialan
Microraptor and Rahonavis have comparable ratios to dromaeosaurids.
- posterior trochantor present.  This is present in Bagaraatan,
therizinosauroids, Avimimus and the avialans Rahonavis, Archaeopteryx and
enantiornithines.
- sickle claw.  Also in the avialans Microraptor and Rahonavis.
So the only characters still diagnosing this clade are those unknown in
basal avialans, which I think make more sense as (Troodontidae +
Eumaniraptora) symplesiomorphies lost in avians, considering all the
characters dromaeosaurids share with birds that are lacking in troodontids.

> The evil question -- what is included in Aves here? Only *Archaeopteryx*
and
> *Rahonavis*, in which case Metornithes respectively Pygostylia might fall
> out somewhere else...?

Archaeopteryx is mainly used, but information from Rahonavis,
Confuciusornis, Hesperornis and Ichthyornis is used if it is unknown in the
former genus.  I seem to recall him mentioning alvarezsaurids as birds
somewhere, but can't find it now.  I agree that having Alvarezsauridae a
separate OTU would have been a good idea, but this was mainly about basal
theropods.

Mickey Mortimer