Systematics and Evolution of the Conoidea

Abstract

The highly diverse toxins of cone snails have been known since the 1970s; however, the evolutionary processes that led to both the species and toxin diversity in the group are only recently being explored. Furthermore, their closely related, also venomous but much more diversified, allies in the superfamily Conoidea remain largely unknown, with most species still undescribed and only few toxins characterized for a handful of conoideans other than cone snails. This chapter is a review of the literature dealing with systematics and evolution of the Conoidea. In particular, it will be shown how new hypotheses on the evolutionary processes have emerged from interdisciplinarity between ecology, taxon-omy, phylogeny, anatomical study, and toxinology. It is becoming increasingly well documented that conoidean diversification is actually linked to toxin diversification: recent results tend to show that the venom apparatus played a major role in the evolution of the group by offering sets of unique molecular adaptations for efficient interactions with other taxa of marine animals. These, in turn, enhanced capacities of conoideans to efficiently compete for new ecological niches, a remarkable example of which is the appearance of fish hunting in cone snails. Speciation in conoideans was also promoted by other factors, e.g., episodic losses of planktotrophy that led to reduced dispersal abilities and intensive allopatric differentiation. Testing such hypotheses remains primarily based on the accumulation of data on the diversification patterns (in particular on