Ranella

Ranella is a genus of medium to large predatory sea snails, commonly known as frog shells or toad shells. These marine gastropod mollusks belong to the family Ranellidae. Ranella shells are typically ovate and inflated, with a thick, heavy shell that often features prominent axial ribs and spiral cords. The aperture is usually elongate and narrow, with a short siphonal canal. The outer lip is often thickened and reflected.

Species within the genus Ranella are found in warm and tropical waters worldwide, inhabiting shallow subtidal to deep-sea environments. They are carnivorous and feed on a variety of invertebrates, including other mollusks, echinoderms, and crustaceans. Their predators include larger fish and predatory gastropods.

The genus Ranella was first described by Jean-Baptiste Lamarck in 1816. Notable species include Ranella gigantea, Ranella olearium, and Ranella vexillum. These shells are often collected by shell enthusiasts due to their distinctive and attractive appearance. Fossil records indicate the presence of Ranella-like shells dating back to the Eocene epoch. The family Ranellidae, to which Ranella belongs, is characterized by its members' robust shells and predatory habits. Research continues to explore the evolutionary relationships and ecological roles of Ranella species within their marine ecosystems.