Follow up: Character significance of Sinovenator

["Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>]

Forgot to add the following:

The addition of the very dromaeosaur- and Archaeopteryx-like Sinovenator as
the basalmost troodontid, the very troodontid- and Archaeopteryx-like
Sinornithosaurus as the basalmost dromaeosaurid strongly suggests that the
common ancestor of deinonychosaurs (and of eumaniraptorans as a whole) was
not too different morphologically from these forms.  In fact, I wouldn't be
surprised if it didn't look a lot like Archaeopteryx overall (not
necessarily all the details, though).  Sinvenator is a little guy,
incidentally: estimated at less than 1 m long.

Incidentally, given the arrangement of (Alvarezsauridae ((Oviraptorosauria
Therizinosauroidea) (Avialae (Dromaeosauridae (Sinovenator
advanced.troodontids)))), an opisthopubic pelvis is now most likely at the
base of Metornithes (and lost in oviraptorosaurs, some dromaeosaurs, and
adanced troodontids).

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796