Calliostoma bullatum

Calliostoma bullatum is a species of sea snail, a marine gastropod mollusk in the family Calliostomatidae.

Distribution
Fossil evidence indicates that this species formerly lived as far north as what is now the Mediterranean Sea, but presently it is only known from abyssal habitats off the coast of West Africa, where it largely lives among deep-water coral reefs.

Description and rediscovery
This species is notable for being described as a fossil well before live individuals were found. The species was originally described from fossil specimens from early-mid Pleistocene outcrops in southern Italy. After over a century, live individuals were found in deepwater reefs off the coast of Mauritania. This makes C. bullatum an example of a fossil Lazarus taxon.