origins of the beak

[zen_mantid]

I have always thought that the ceph beak was derived from the ancestral molluscan radula. Now that I know they also have radulas, I wonder if b oth are derived from the ancestral radula. I cannot find anything online about it, nor did my searches here succeed.

Does anyone have any information on this?

Thanks!

 

[OB]

Hi there zen_mantid and to Tonmo! I would expect the beak not to be derived from the "ancestral" radula proper, as it appears more as a chitinized edge on the sphincter muscle lining the "ancestral mouth". I remember PZ doing a blog entry on beaks back in 2006, so hyperlinked herewith. have fun in our little corner of the web!