Re: again: frill of Triceratops

[ali1020@tam2000.tamu.edu]

A lot seems to be said about the frills of ceratopsians but probably a 
little evolutionary analysis would help. First of all I would like to 
know if the belief that the pachycephalosaur skull margin ornamentation 
and the ceratopsian frill are homologous is well established. Anyhow I 
assume that to be the case and believe that the frill evolved through a 
process of reinforcement. Initially it evolved  due to sexual selection. 
Subsequently it gave a an oppurtunity for jaw muscle attachment and again 
it was reinforced by sexual selection. Possibly this occurred  many 
times in evolution like the Austropithecus. robustus cranial crest. I 
feel that in cicadelloids the ornamentation of thoracic segment 3 also 
arose by such a process. So it is very possible that full use is made of 
any new organ to do all possible things.

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