Radular teeth of <i>Conus</i> (Mollusca: Neogastropoda: Conidae) from the Red Sea: comparative morphology and character analysis

Abstract

Hypodermic needle-like radular teeth characterise predatory gastropods of the genus Conus. They inject neurotoxins that disable their prey, which is then swallowed whole. Until now, these structures have received limited use in assessing the range of intraspecific variation within and interspecific differences among closely related species. However, radular tooth characters deserve greater attention, especially because they conform more closely with molecular phylogenetic data than do more conventionally used external shell characters. This report describes radular tooth morphology of 16 Conus species from the Egyptian coast of the Red Sea, representing the three commonest feeding guilds in the genus: vermivores (12 species), piscivores (2) and molluscivores (2), and provides SEM images of all. This study gives the first description of the radula teeth of C. (Virroconus) sinaiensis. Multivariate ordination methods applied to quantitative characters separate the vermivorous species mainly into two distinct groups and distinguish between the closely related species C. (Virgiconus) flavidus and C. (Virgiconus) frigidus, confirming the ability of these methods to assess intraspecific variation within and interspecific differences between closely related species. Similar studies supported by molecular markers in other Conus species groups are needed to further test phylogenetic hypotheses of relationships throughout the genus.