Re: Chimeras (was Re: Protoavis & Drepanosauridae (sensu Renesto, 1999)

["T. Mike Keesey" <tmk@dinosauricon.com>]

On Mon, 30 Apr 2001 Dinogeorge@aol.com wrote:

> Thanks for clarifying what you meant. If Chatterjee's phylogeny is correct,
> then Protoavis doesn't affect BCF one way or another except to push back the
> origin of avialan birds, and consequently the origin of volant theropods.

Yes, but those volant theropods are still just avialans -- nothing more
basal than that. Chatterjee's phylogeny in his book looks exactly like the
usual phylogenies except for the inclusion of _Protoavis_ as an avian more
advanced than _Archaeopteryx_. In his model of flight origins, he portrays
the ancestral eumaniraptor (in his words, "protodromaeosaur") as a
tree-climbing but non-volant animal. He agrees with the "orthodoxy" that
flight arose after the divergence of _Deinonychosauria_ and _Avialae_.

The time this animal is from doesn't make any kind of difference -- what
matters is where it fits into the phylogeny. If it's an avian, then it
says nothing for or against BCF. If it's a basal theropod, THEN it
supports BCF, regardless of its time period.

> It's a lot easier to accommodate Protoavis in BCF than it is in the BADD
> (birds are dinosaur descendants) phylogeny.

But Chatterjee is in the BADD (:P) camp.

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