coffee bean snail

The Coffee Bean Snail (Melampus coffea) is a small amphibious pulmonate gastropod in the family Ellobiidae, taking its common name from the resemblance of its dark, ovoid shell to a coffee bean. Adults typically measure 8–15 millimetres in shell height and display a dark brown to blackish shell with subtle white banding. Unlike fully aquatic snails, Melampus coffea breathes air through a lung-like mantle cavity and inhabits the high-intertidal and supratidal zones of tropical mangrove forests, salt marshes, and rocky shores, where it grazes on algae, decaying leaf litter, and organic detritus on mangrove roots and prop roots above the waterline. This species has a broad distribution across the Indo-Pacific region—including shores of East Africa, South and Southeast Asia, the Pacific Islands—and along tropical Atlantic coasts of the Americas and West Africa, reflecting its tolerance for both Pacific and Atlantic mangrove systems. Population density can be remarkably high in productive mangrove habitats, where the species plays a role in decomposition and nutrient cycling. Coffee bean snails disperse via oceanic rafting on flotsam, contributing to the wide geographic range. The species is assessed as Least Concern by the IUCN. Despite being overlooked compared to larger marine invertebrates, Melampus coffea serves as a food resource for shorebirds and crabs.