Compsognathus/Sinosauropteryx (was RE: Yixian Dating Again)

["Williams, Tim" <TiJaWi@agron.iastate.edu>]

john maynard wrote:

> i am confused. are you saying that you believe that sinornithosaurus 
> and microraptor were avialans or eumaniraptorans? 

Avialae (birds) is a group *within* the Eumaniraptora.  Current phylogenies
place _Sinornithosaurus_ and _Microraptor_ within the Eumaniraptora as
members of the Dromaeosauridae, and therefore outside the Avialae.  The
Deinonychosauria (dromaeosaurids + troodontids) is the sister taxon to
Avialae within a monophyletic Eumaniraptora.

BTW, any of these configurations may change regarding _Sinornithosaurus_ and
_Microraptor_ - such is the nature of phylogenetic nature.  For example,
future analyses may put both or either of these genera outside of both
Dromaeosauridae and Avialae as  as basal eumaniraptorans, or as basal
deinonychosaurs outside of Dromaeosauridae and Troodontidae.


> I believe that sinosauropteryx should be put in its own family, 
> sinosauropterygidae and in a superfamily with the compsognathids.

 At the moment, _Compsognathus_ and _Sinosauropteryx_ (?and _Aristosuchus_)
seem quite happy together in a single family, which takes the name
Compsognathidae.  Who knows what tomorrow might bring?

> How many fingers did sinosauropteyx have? i have seen it 
> illustrated with 2 sometimes, and more often 3. 

All scientific descriptions of _Sinosauropteryx_ refer to three fingers per
hand in this theropod, AFAIK.  I can't see why this critter would be
restored with only two manual digits - especially since recent descriptions
of _Compsognathus_ give this genus three digits on the hand as well (i.e.
Paul was probably correct in PDW).



Tim


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Timothy J. Williams, Ph.D. 

USDA-ARS Researcher 
Agronomy Hall 
Iowa State University 
Ames IA 50014 

Phone: 515 294 9233 
Fax:   515 294 9359