Cephalopods like octopus and squid are well known for their repertoire of sophisticated behaviors governed by their elaborate nervous systems that are comparable in size to complex vertebrates, but with radically different organization. Cephalopods diverged from basal molluscs such as slugs and snails, and the course of their evolution is characterized by striking examples of convergent and divergent evolution in relation to vertebrate organisms. Yet, molecular innovations that give rise to novel behaviors among these fascinating animals remain relatively unexplored.
