Re: Revising Hou et al, 96 (very very long)

["Fam Jansma" <fam.jansma@worldonline.nl>]

Tim Williams wrote:

>I might be missing something, but the similarities shared by
>_Sinornithosaurus_ and _Archaeopteryx_ are likely to be primitive
>eumaniraptoran traits.  These include the long forelimbs and broad pinnate
>feathers.  The stiffened tail (elongated prezygopophyses & chevrons) is
>probably a derived dromaeosaurid character, just as the fused pygostyle is
>a derived avialan character.
>
Leading me to expect that Sinornithosaurus is trully a basal Dromeosaur
which is very close in morphology to Archaeopteryx, as I stated earlier this
thread. And not, as HP Mickey Mortimer thought, closer to the avialans.
Although it would be interesting to know on what evidence he based his
question upon... As time goes by, maybe some transitional fossils will be
found.
>
>For other theropod lineages, the SLC may have been a disadvantage,
>promoting the degeneration of this structure.  Taxa such as
_Protarchaeopteryx_ might have reverted to a more primitive carpal
configuration to give the wrist
>more overall flexibility - especially torsional and dorso-palmar movement.
>
Protoarchaeopteryx is probably a very basal Oviraptorid, but not enough is
known of it to say wether this is true or not, so it didn't have to have had
one in the first place. Things could have evolved by means of convergence,
just as that protofeathers evolved a couple of times in history, can you say
Longisquama? But for what means could it have used it's new found
flexibility for, if it was reversed as you have said/ wrote? Alright, a very
difficult question to answer, since it's for most part speculation, but does
someone have any idea?
>
>Tim
>
Rutger Jansma