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Sails, heat, and sex [Re: Suchomimus prey?]



--On Tuesday, April 06, 1999, 2:06 AM +0000 archosaur@usa.net wrote: 

> 
> used their sails for sexual purposes instead of just radiation.

        Indeed, it is very likely that the sails were used for more than a
single purpose.  It is true in very warm climates today that anything that
sticks off the body may be used as a radiator (elephant ears are almost
cliche, so let us use giraffe necks).  Animals that don't have these
radiators admittedly do well without them, but again, they must be viewed as
an advantage.  
        In addition, the parts that stick off are also usually used in
sexual contests.  Giraffes (maybe not a great example) "neck"-have shoving
contests using their necks- and elephants spread their ears to look larger. 

 
> Course we should be able to see some difference in sail height within
species
> right? Do we even have enough skeletons to compare yet?
> 
> Knowing nature, it's probably choice D, all of the above.

        It is interesting to compare _Baryonyx_ with _Suchomimus_.  The two
are incredibly similar in overall form, but _Baryonyx_ has that nice big
sail.  These two animals are from *about* the same time and their similarity
suggests that a land bridge between Europe and Africa was present or only
recently departed.  This may be the variation you are searching for, might
even be the feature that arose in genetic isolation that later lead to
behavioural mating isolation between the two genera.  
        What is also interesting is that _Baryonyx_ comes from an area of
possibly more temperate climate while _Suchomimus_ was from the hotter
south.  Could this have been the stimulus selecting for the larger sail?  It
is always dangerous to try and suggest a reason for evolution to work, so I
will leave this as a question.  

Jack