Re: Cursorial adaptations (was T.rex and elephants)

[rjmeyer@ix.netcom.com (Rob Meyerson)]

Dinogeorge writes;

>In a message dated 97-10-05 07:09:48 EDT, jwoolf@erinet.com writes:
>
><< So maybe we could reasonably envision a scenario something like this:
> Short-frills spar with horns at mating time -- an active method of
> settling conflicts.  Because of the potential for serious injury to both
> parties, this isn't a very good method of settling disputes.  So, over
> time the long-frills develop so that the active conflict can be replaced
> by less direct passive conflicts of displays.  Whoever has the most
> impressive display wins.  Only in two very well matched individuals
> would the old method of active combat come into play. >>
>
>Except that frills evolved >before< horns, so the displaying occurred even
>when there weren't any horns. This suggests that the horns evolved to settle
>disputes when the frill displays weren't sufficient...

I think we are trying to compare two separate types of evolutionary development 
here.  I suspect that the frill and the horns developed independantly of each 
other.  Later on, both features were incorporated into a common defensive 
strategy (question: do the really ornate ceratopian frills appear after the 
more complex horn arrangements?).  Just a quick observation, but I think that 
frills developed first as a way to increase chewing power.  As the horns 
developed, and got more deadly, the frills began to take on an additional 
bluffing role (we can quibble on whether the original purpose of increased 
chewing power was maintained throughout the chasmosaurines career).


Shalom,

Rob Meyerson

***
"Keep your stick on the ice."
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