What is BCF? (was No more paedomorphosis, bah)

[Jonathon Woolf <jwoolf@erinet.com>]

Dinogeorge wrote:

> In a message dated 98-04-14 22:39:55 EDT, m_troutman@hotmail.com writes:
>
> << So, since I believe that flight came from an arboreal existence, I
>  believe in BCF? I have always supported the arboreal origin of avian
>  flight and find no incongruencies between theropod anatomy and arboreal
>  lifestyle in some of the smaller, birdlike species.  >>
>
> You're close. As soon as you agree that many, perhaps all, theropods descended
> from ancestors that were capable of some kind of flying (I'm using the general
> definition, not specifically ornithopting, as I noted in an earlier post),
> you're there.

This statement seems to rather neatly complete a paradox that I've been
puzzling
about, Dinogeorge.  On the one hand, you say that "many, perhaps all"
theropods
descended from flying ancestors.  On the other hand, you've said to me
in the past
that the very oldest theropods, like _Eoraptor_ and _Herrerasaurus_,
aren't
particularly birdlike because they existed before the evolution of
birds.

What _exactly_ does BCF say?  _Which_ theropods are supposed to be
descended from
birds?  The very birdy dromaeosaurids?  The less birdy tyrannosaurs or
allosaurs?
Ceratosaurs?  Herrerasaurs?  At what point did the "bird/advanced
theropod" line
branch from the basic "dinosaur" line?  All coelurosaurs?  All
maniraptoriforms?
Did it happen before the prosauropods split from the theropods, thus
making the
entire Dinosauria nestle nicely inside a stem-based "birds" clade?

No need to hurry in answering <g> -- for the next five days I'm off to
Dinofest,
and won't be checking my e-mail til I get back.

-- JSW