As pointed out by Moller et al (Evolution 2005 44(49):15986-96), conotoxin  vI14a (a member of conotoxin Peptide Framework XIV) possesses a conserved structural feature in K(+) channel blockers. This feature is found in the peptide toxins of both scorpions & cone snails. They suggest a common ancestral genetic origin.

While I'm not an expert in neither phylogenetics nor cladistics, the last common ancestor of both molluscs & scorpions are thought to be the bilaterians. The bilaterian body plan & its molecular repertoire were born during the so-called Cambrian Explosion. As potent defensive & offensive toxins were needed from this early stage, I think it is highly likely that Peptide Framework XIV did have a common genetic origin & is not the result of convergent evolution leading to such diverse forms as scorpions & cone snails.

Jack

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