Comparative Morphology of Radular Teeth in Conus: Observations with Scanning Electron Microscope
Radular teeth of 22 Indo-Pacific species of the genus Conus (Neogastropoda: toxoglassa) were compared. On morphological features all can be related to one of three known feeding modes: piscivorous, vermivorous and molluscivorous. Observations are reported on the radular teeth of six piscivores, thirteen vermivores and three molluscivores. The radular teeth of piscivores are of two general types. In the first, two barbs and a posteriorly-directed process with a recurved tip are found at the anterior end. In the second, two barbs are located at the anterior end and the shaft is serrated for most of its length. An enlarged posterior region (terminal knob) is present in the first and absent in the second. Molluscivores possess radular teeth with two anterior barbs and in some species a serrated shaft or terminal knob. The radular teeth of vermivores, which show much greater interspecific variation than those of piscivores or molluscivores, are characterized by one or two anterior barbs and in most species a serrated region near the apex. A forwardly-projecting cone (basal spur) is usually located on the terminal knob. Piscivores and molluscivores lack such basal spurs. The radular teeth of Conus are used to convey a potent venom and hold prey firmly during feeding. Previously undescribed morphological features are noted on the teeth of C. obscurus and C. lividus. Figured here for the first time are the radular teeth of C. abbreviatus, C. aureus, C. catus, C. litoglyphus, C. pennaceus, C. rattus and C. sponsalis.