Siphonarioidea

Siphonarioidea is a superfamily of marine gastropod mollusks, commonly known as false limpets. These mollusks are characterized by their conical shells that resemble those of true limpets (Patellidae), but they belong to the Pulmonata, a group of snails that typically breathe air. This evolutionary adaptation allows siphonariids to inhabit intertidal zones where they are exposed to air during low tide. Their shells possess a distinct internal ridge or septum, which is a key feature differentiating them from true limpets.

Siphonariids are found in tropical and temperate waters worldwide, inhabiting rocky shores and other hard substrates in the intertidal and shallow subtidal regions. They are herbivores, feeding on algae and diatoms scraped from rocks. Reproduction in Siphonarioidea is varied, with some species having external fertilization and others internal fertilization. The larval stages can be planktonic, contributing to their dispersal. Despite their superficial resemblance to true limpets, their respiratory system and other anatomical features clearly place them within the pulmonate lineage, showcasing a remarkable instance of convergent evolution for a marine lifestyle.