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Re: Paedomorphosis ( Re: BARYONYX' CLAWS )
In a message dated 98-04-13 03:10:46 EDT, email@example.com writes:
<< Thus, unless a fossil shows up that is both a clearly and considerably
specialized volant or near-volant form and obviously represents an ancestor to
both birds and at least some theropods, the "difference" between BCF and BADD
may be minimal, unimportant or impossible to distinguish. >>
We already have such a fossil, although it is somewhat later in the fossil
record than I'm comfortable with, namely, _Rahona_, the flying dromaeosauroid.
I'd like to see a _Rahona_-like dinosaur in the Middle Jurassic (lotsa luck!).
If you pin its advocates down, they will aver that BADD makes no statement
about the lifestyle of the common ancestors of birds and theropods. But some
BADD advocates consider that the common ancestors of birds and theropods were
cursorial animals that started to live in trees only after they became powered
fliers on the ground (see, e.g., Kevin Padian's recent articles on this
issue). BCF asserts that the arboreal lifestyle came first (so I should call
it ALCF rather than BCF), and that birds developed powered flight
(ornithopting) only after a lengthy evolutionary history as arboreal animals.
These are the major differences between the two paradigms.