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

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.



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