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Re: New dinobird "Sinovenator" (the basal _Troodontid_)



You wrote:

>Note that this is a simple addition of Plesion Sinovenator to my
>previous classificiation (along with the proposed elevation of troodonts
>from plesion status to full Ordinal status).  I actually suspect that
>Sinovenator will actually be a member of Archaeopterygiformes, more derived
>than Family Dromaeosauridae (sensu stricto).   But it may remain as a
>separate clade unto itself (as above) or possibly even a basal clade of
>Troodontiformes (my third choice at the present time).  If more primitive
>troodontiforms are found, I would expect them to be propubic to mesopubic
>(not opisthopubic like Sinovenator).  We shall see.

And based on what? Characters like the dentary foramina inside a deep
groove, large number of dentary teeth, no basisphenoid recess, robust
metatarsal IV, all seem to point to a Troodontid relationship. That some
characters might not be present, such as the inflated braincase or the
lateral depression are advanced characteristics within this family and
wouldn't be expected in such a basal creature. If it did have these
characters, nothing basal would be about Sinovenator and so on would be
considered as a advanced Troodontid.
The overall similarities to Archaeopteryx can also be explained by it's more
basal position in the Deinonychosauria, since (what a suprise) it has
evolved from a Archeopteryx type of creature. Greg Paul must be laughing his
pants of since he was the one who thought a decade ago or so that the
"maniraptors" were secondary flightles and had to have evolved from flying
ancestors. All but a few took him seriously in saying that, but in the ast
few years more and more evidence is building up that he was indeed correct.
I think we all need to give HP G.S. Paul a very big appologie! :)
The last character Ken describes, that if more primitive Troodontids are
found, they would have had propubic to mesopubic pelves. I don't think Ken
has been looking at a skeletal reconstruction of Archaeopteryx lately since
again this creature shows a opisthopubic pubis. The opisthopubic pelvis is a
primitive character for the "maniraptorians" as it seems and the slight
propubic pelvis of the Oviraptorids seems to be an advanced feature in the
family.

Alright Ken, your turn :)

Rutger Jansma