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Re: FW: Concavenator corcovatus, a new humped carcharodontosaurid from Las Hoyas

On Thu, Sep 16th, 2010 at 9:27 AM, dale mcinnes <wdm1949@hotmail.com> wrote:

> If sexual behavior is at the root cause of the elongation of spine growth 
> then, 
> why DON'T we see more of this in other clades?? This should be occurring 
> everywhere 
> since sexual selection is also everywhere in every clade and NOT dependent on 
> envir-
> onmental regimens. 

There are numerous reasons why neural spine elongation wasn't always the 
'sexiness of choice':

1) Not all species may have used visual displays to attract mates. Some may 
have used scent, 
song, or courtship 'dances'. Sometimes all you need to get the girls is to be 
able to kick your 
opponents' arses in intraspecific combat - where in fact a lack of impeding 
adornments might even 
be an advantage.

2) Of those that used visual displays, bright colouration may have been 
preferable to changes in 
body form. Perhaps those species that resorted to costly changes in body form 
simply lacked the 
genetic resources to evolve bright colours or bold markings.

3) Elongated neural spines may have been just one type of display structure. 
Crests, frills, horns, 
spikes and plates may have also been primarily for display purposes in some 


Dann Pigdon
Spatial Data Analyst               Australian Dinosaurs
Melbourne, Australia               http://home.alphalink.com.au/~dannj