Re: how does one...? was Re: JVP 27(1)

[Tim Williams <twilliams_alpha@hotmail.com>]

Cliff Green wrote:

>     FYI, I do not believe Steven Czerkas's claim in "dinosaurs of the 
> air",
> that dromaeosaurs are birds. That doesn't mean I think he should have his
> name blotted out of the science for heresy.

Sorry, yes, "infamous" is probably an overstatement.  I was emphasizing the 
point that the volume in question has a reputation for having its 
conclusions questioned and even overturned.  Apologies to Cliff, or anyone 
else that took offense.

The idea that dromaeosaurids may be secondarily flightless is actually not 
all that radical/heretical.  But Czerkas goes much further than this, 
arguing that theropods are diphyletic - i.e., can be divided into one 
lineage (Maniraptora) that includes birds and dromaeosaurs; and a second 
lineage that includes the majority of non-avian theropods.  Czerkas's 
argument runs that maniraptorans (including birds) and "theropods" (the 
leftovers, like carnosaurs and ceratosaurs) evolved independently from 
separate basal archosaur stock.  The problem is that it is very difficult to 
support such a hypothesis without ignoring the multitude of shared derived 
characters that all theropods have in common.

Cheers

Tim

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