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Re: linguistic analogy

On Mon, 12 Feb 1996, Rob Meyerson wrote:

> >   It's my understanding that many dinosaurs have deep sternums.  The
> >sternum of _Mononykus_ is referred to as "keeled," as is that of
> >_Archaeopteryx bavarica_.  The only difference is that modern birds have a
> >HUGE sternum, whereas in certain theropods it was merely large.  Can a size
> >difference be sufficient to mark something as "different enough" for its own
> >category?
> One possible problem with this is that these two appear after Archy,
> AFAIK.  This would again suggest the possibility that the sternum
> solidified sometime later.
> However, if it can be shown that the sternum was already in place by
> Archy's appearance, I would have to say "No, they aren't different
> enough to put in different taxa."

Most or all theropods had at least a cartilagenous sternum.  The sternum 
only became big and keeled when it was needed for flight.

> Rob

Nick Pharris
Pacific Lutheran University
Tacoma, WA 98447

"If you can't convince them, confuse them." -- Harry S Truman