Monoplacophora is a class of mollusks thought to be extinct until 1952, when a living animal was dredged up from deep marine sediments. They have a single, flat, bilateral shell that is often thin and fragile. About two dozen living species of monoplacophorans have now been discovered, all living in deep sea trenches.
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- Monoplacophora Information from Wikipedia about this class of mollusks, thought until recently to be extinct, their description and classification.