The Mollusca is the largest marine phylum, featuring about 85,000 species that are alive today (and which the term extant denotes). Nearly one in four of the known organisms in the ocean are mollusks, and many live in freshwater as well. This highly diverse phylum is divided into ten categories. Seven phyla are alive, one is extinct, one is a proposed clade (a group of organisms believed to have evolved from a common ancestor), and the remaining category is used to denote mollusks of uncertain systematic position. Examples of mollusks include clams, snails, and octopus. This article will summarize each of these types and additional articles will follow to provide more details about each edible type.
The Ten Classes of Mollusks
1. Apolacophora — Apolacophorans are unlike other mollusks as they have no shell. These worm-like animals burrow through the sand.
2. Bivalvia — Bivalves include clams, oysters, mussels and scallops. Bivalves are an excellent source of protein and contain a number of vitamins and minerals including Vitamins C, Iron, Manganese, Phosphorous, Selenium, Zinc. Bivalves are the #1 source of Vitamin B12 (known as Cobalamin). Foods high in Vitamin B12 help prevent anemia, fatigue, mania and depression. Bivalves are easily digested and commonly served raw. Bivalves should always be purchased and cooked (or consumed) when live. They should not be consumed when both frozen and raw.
3. Cephalopoda — Cephalopods include octopuses, squid and cuttlefish. Octopus is another one of the best sources of Vitamin B12 and also includes high amounts of Potassium (Vitamin K), Phosphorous, Sodium and Selenium.
4. Polyplacophora — Polyplacophorans include Chitons (formerly Amphineura). Sometimes called sea cradles and loricates. These have a shell that features eight separate valves (or shell plates).
5. Gastropoda — Gastropods include snails and slugs. Snails are also known as escargot, conch, and periwinkles. They contain Niacin, Iron, Magesium, Phosphorus,Potassium and Selenium.
6. Monoplacophora — Monoplacephoronas are deep-sea creates that resemble a clam with no bottom shell. Extant representatives were not discovered until 1952 and had been thought to be extinct.
7. Pleistomollusca — Pleistomolluscans are a proposed clade within the Mollusca that unites gastropods with bivalves (accounting for 95% of mollusks). This proposal is based on similarities observed with molecular analysis.
8. Rostoconchia — Rostroconchians is a class of extinct mollusks from the early Cambrian to late Permian periods (the time when a profound change on Earth occurred and the vast majority of life forms emerged in a relatively short period of time called the Cambrian Explosion).
9. Scaphopoda — Scaphopods (or Shovel-footed) mollusks have long, thin tusk shells that are sometimes found along the seashore but which live offshore.
10. incertae sedis — Latin for “uncertain placement”, this taxonomic group contains additional mollusks that are currently of unknown phyla.
Coming soon, additional articles will focus on the three most popular (and edible) types of Mollusks: the Bivalves, Cephalopods and Gastropods.