RE: Peering at review

["Williams, Tim" <TiJaWi@agron.iastate.edu>]

Dinogeorge wrote:

> What is definitely >not< obvious is the evolution of theropods to birds 
> from the ground up, for which there have been any number of  wild and 
> wacky proposals in the peer-reviewed, published literature, [snip]
> BCF argues that this phyletic string of common ancestors comprised 
> animals that always looked much more like modern birds 

Yeah, OK.  But I think the reason why paleontologists take issue with the
BCF scenario is that there is absolutely no evidence for it.  Tree-dwelling
basal dinosaurs that looked more like modern birds than _Archaeopteryx_ or
_Microraptor_ did?  It's a nice story; but there isn't a shred of evidence
in support of it.

> (i.e., small, arboreal, feathered) than they looked like the usual image
> of terrestrial cursorial theropods. 

OK, I'll take the bait.

First off the bat... there really is so need to invent Triassic gliding
dino-birds at the base of the Dinosauria when the fossil record has already
produced small arboreal maniraptorans that look a lot like _Archaeopteryx.  

Secondly, I really wish you wouldn't continue to equate a maniraptoran
origin of birds with a "ground-up" origin of avian flight.  I know certain
ornithologists who delight in conflating the two, for purely mischievous
reasons, but I think "dinosaurologists" ought to know better.  

Thirdly, the earliest known theropod to show evidence of powered flight
abilities is _Archaeopteryx_.  I know certain folks (George among them) are
attracted to the notion that there were all sorts of winged dino-birds
fluttering around in the Triassic, but there is absolutely NO evidence of
the existence of these critters.

I think one reaches a point where ones imagination overreaches the available
evidence.  BCF is one of those scenarios that has catapulted itself way
beyond the fossil data.


Tim