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Re: DROMAEOSAUR "SICKLE" CLAWS



Casey Tucker or Jonathan Woolf wrote (sorry, I'm loosing sight of 
who says what in this discussion):

> > Paleontologists aren't sure yet what sabercats used their sabers for.
> > In fact, there seems to be as much debate over that as there is over
> > dromaeosaur claws. <g> We only know that exaggerated fangs is a
> > repetitive trend in felid evolution, with at least four separate lines
> > yielding sabertooth or dirktooth forms.  The snow leopard is an
> > incipient fifth longtooth form, but right now its fangs are simply
> > unusually long for its size.  Nowhere near as exaggerated as
> > _Smilodon_'s sabers or _Deinonychus_'s big claw.

Chris Campbell answered:
> Perhaps my info's outdated, but I thought it clear that _Smilodon_ used
> its teeth to effectively hunt and kill juvenile mammoths.  It's build
> certainly supports the idea, and there are some crazy lions and tigers
> even today who hunt elephants, so the concept isn't completely unheard
> of among felids (or their kin, as the case may be).

The first creatures that developed saberlike fangs were the 
gorgonopsians and pristerognathid therocephalians. They possibly used 
this fangs for hunting the large dinocephalians and pareiasaurs (a 
bit equivalent to the Smilodon-mammoth 'relationship'). Gorgonopsians 
and pareiasaurs might even have formed a 'co-adaptive pair'. 
Gorgonopsians evolved in larger, more robust and larger fanged forms 
(for example Dinogorgon and Inostrancevia) whereas their supposed 
pareisaur prey become more armoured (for example Pareiasaurus and 
Scutosaurus). Both groups became simultaneously extinct and the end 
of the Permian.
(as far as I know however, there are no indications that dromaeosaurs 
evolved their large sickle claws in co-adaptation with their supposed 
prey; is the principle of co-adaptive evolution still accepted 
anyway?)
Sorry, therapsids again...

Pieter Depuydt