Malacology is the scientific study of molluscs (phylum Mollusca), the most diverse living group of animals. There are around 130,000 living species of molluscs, including forms as diverse as giant squid and tiny pea clams.
The phylum Mollusca is divided into nine taxonomic classes including gastropods (snails and slugs), bivalves (clams, mussels, oysters etc.), cephalopods (cuttlefish, squids, octopuses etc.), scaphopods (tusk shells), Polyplacophora (chitons), Monoplacophora, two groups of aplacophoran worm-molluscs and the extinct Rostroconchia. Most species of molluscs carry a calcareous shell covering the soft-bodied animal but many groups do not have a shell (terrestrial and marine slugs, most cephalopods, aplacophorans), or have shells or armour with diverse adaptations: dorid nudibranchs or sea lemons have an internal skeleton made of spicules, the scaly-foot snail Chrysomallon squamiferum has scale-armour, or the family Juliidae are tiny green snails with a bivalve-like shell.
Molluscs inhabit marine, land and freshwater habitats and are important members of nearly every ecosystem and food chain. Molluscs are an increasingly significant global food source for humans. And mollusc shells are used in many ways for jewellery and arts and crafts. Some species are vectors of parasites which cause severe human diseases. Fossil shells are used to determin the stratigraphic age of rocks and to reconstruct of past ecosystems and climate.
Pollution and habitat destruction threaten many molluscs, especially terrestrial gastropods and freshwater bivalves that are in danger of extinction and need conservation measures. Some attractive seashells like the giant Tridacna clams may not be traded under the law of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Work in our section has contributed to recognising species under threat of extinction through the IUCN Red List of Threatened Species.
