_Sinornithosaurus_

["T. Mike Keesey" <tkeese1@gl.umbc.edu>]

Just a couple of thoughts/questions about this latest awesome dinosaur
find from Liaoning.

The authors claim it as evidence for a "Ground Up" model of flight
evolution for birds, since it had the "prerequisites" of long arms and an
Archie-like shoulder. But since they claim that it is more primitive than
other members of a non-flying clade (Deinonychosauria), wouldn't it make
sense to interpret _Sinornithosaurus_, which has more flight
characteristics than more derived deinonychosaurs, as representative of an
intermediate stage in the evolution from a flying ancestor to secondarily
flightless deinonychosaurs?

Secondly, it's been called a primitive dromaeosaurid, but if it clades
outside of _Dromaeosaurus_ and Velociraptorinae, I believe it should
instead be a non-dromaeosaurid deinonychosaur.
 (Dromaeosauridae == {_Dromaeosaurus_ + _Velociraptor_} and
  Deinonychosauria == {_Deinonychus_ > Neornithes})

--T. Michael Keesey
tkeese1@gl.umbc.edu | THE DINOSAURICON: http://dinosaur.umbc.edu/
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