Re: paraphyletic Dromaeosauridae (Variraptor)

["Ken Kinman" <kinman@hotmail.com>]

   Of course, some of this may be a rooting problem of some kind.  I can't 
help but wonder if their isn't some bias (in computer programs or deep in 
people's brains) to have smaller forms like Microraptor split off earlier 
and larger forms then appear more derived by default.  I hadn't seen Xu et 
al.'s (2000) topology, but it just looks sort of upside down to me.
     And sometimes perhaps there is also a tendency for groups to appear to 
clump together in one clade, when they really are a paraphyletic series of 
adjacent clades (as we discovered with Ceratosauria sensu lato).
    But as you say, the more new forms we discover, the more we can refine 
things.  That's what keeps things interesting.
        ---------- Ken
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Jaime wrote:
The more basal forms appear to have been the most avian in form, and that 
the derived dromaeosaurids were the least
> avian. This seems ever more poignant with the analysis of Xu et al., 2000,
> where the phylogeny can be adapted to suit this explanation:
>
>   --+--*Microraptor*
>     `--+--*Sinornithosaurus*
>        `--+--+--*Velociraptor*
>           |  |   `-?-"Ichabod"
>           |  |--*Deinonychus*
>           |  `--*Saurornitholestes*
>           |-?-*Pyroraptor*
>           `--*Dromaeosaurus*
>
>   *Pyroraptor* may actually be a valid velociraptorine, but 
> *Dromaeosaurus* appears to be one of the most derived, rather than basal, 
> dromaeosaurids. I doubt we'll be done with these.

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