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RE: coelophysis



Mike Taylor wrote:

>> "Birds came first". The basic concept is that all dinosaurs can
>> trace their roots to arboreal, possibly feathered/downy
>> archosaurian ancestors. It's an intriguing idea I want to find more
>> about, but so far it seems to me confined to the realm of
>> speculation.
>
> The big, big problem with BCF -- the metaproblem, if you like -- is
> that it's bever been published.


BCF has been published - sort of.  It appeared in a magazine called "Omni" (now 
defunct) about 12 years ago.  Omni specialized in articles on popular 
science and science fiction.  Although BCF fell into the former category, there 
are certain elements that make it sound more like the latter.  The article 
was...


Olshevsky, G. (1994). The birds first? A theory to fit the facts - evolution of 
reptiles into birds.  Omni, June, 1994.


For those interested, the gist of BCF also appears in this DML posting...


http://dml.cmnh.org/1995Oct/msg00734.html


The trouble with BCF - or the metatrouble, if you like - is that it isn't 
really an hypothesis at all.  It incorporates ideas on phylogeny and 
ecomorphology but, 
strictly speaking, it isn't really a phylogenetic hypothesis or even an 
ecomorphological hypothesis.  So it cannot be tested.  Further, the author 
(Olshevsky) 
falls into the trap of assuming that if you have enough faith in your own 
opinions, these opinions can become facts.  For example, BCF holds that the 
_only_ 
way an animal can become bipedal is by first being arboreal.  Another BCF 
"fact" is the concept of a "central lineage", mentioned in the DML posting and 
in 
the Omni article.  This "central lineage" of arboreal "dino-birds" is purported 
to have given rise to all the major dinosaurian groups, including (separately) 
theropods, ornithischians, prosauropods and sauropods (hence, as Mike said, 
even _Brachiosaurus_ is a flightless bird).  


By now BCF might have evolved into a scientific hypothesis, rather than 
remaining as an imaginative "just-so" story.  Olshevsky apparently has a book 
(or 
series of books) on BCF in the pipeline (self-published), so perhaps all will 
be revealed.


> It's not to be confused with Greg Paul's 2F (secondary flightlessness)
> hypothesis, which suggest that that derived manraptors may be
> secondarily flightless birds. That's not widely accepted, but not
> outside the bounds of possibility. 


Yes, unlike BCF, which is BS, GSP's 2F is actually quite OK, IMHO.  


Cheers

Tim






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