Neopilina
Neopilina is a mollusc, the only surviving genus of monoplacophora.
Some molecular results show that they fall within the polyplacophora clade, although these have been called into question. Fossil and morphological data show that they are rather derived and bear very little resemblance to an 'ancestral mollusc'.
The monoplacophora were well-known as a fossil group from the Cambrian to the Devonian. They were thought to be long extinct. 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.
References
Molluscs