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Re: (fwd) Mammals as a cause of Dinosaur extinction




On Thu, 18 Dec 1997, Seth Ellestad wrote:

> Dinogeorge wrote:  >But
> >without the functional, grasping forelimbs, such flightless avians were no
> >longer theropod dinosaurs. So, after serving as dinosaur food for two-thirds
> >of the Mesozoic Era, mammals managed to gain some measure of revenge.
> 
> Not disagreeing with what you are saying in general, but didn't the
> Phorusrhacids ("Fear Cranes", right?) actually have "wings" that had
> reverted into functional, three-clawed forelimbs?  Thereby greatly muddying
> the dinosaur/bird distinction (as if it wasn't enough already)?

I find the "grasping forelimbs" argument to be rather weak.  Modern large
oviparous species suffer relatively little predation on their adult forms.
Ostriches suffer tremendous egg and juvenile predation, as do crocs.  Much
of this (ostriches, anyway) is done at night when grasping forelimbs would
be grasping nothing much else than night air!