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| Monoplacophora | |
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| Pilina unguis | |
| Scientific classification | |
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| Class: | Monoplacophora Nils Hjalmar Odhner, 1940 |
Monoplacophora is a class of molluscs. They have a cap-like shell and live on the bottom of the sea.
They were well-known as a fossil group from the Cambrian to the Devonian. One species was dredged up from the Pacific Ocean off Mexico in 1952. It was found to be a Monoplacophoran, and given the genus of Neopilina. This was one of the most remarkable modern discoveries of a 'living fossil', and a Lazarus taxon.
More than that, they are the most extreme example of the pull of the recent, which is a term in palaeontology. All fossil groups have a first and last appearance in the fossil record but, for living species, their last appearance is the present day. This may be very much later than their last appearance as a fossil. The discovery of the living monoplacs extended their time range by 400 million years.
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