Ylistrum

Ylistrum is a genus of marine bivalve mollusks in the family Pectinidae, the scallops.
There are four species currently in the genus:

Previously, these species were considered to be members of Amusium, but a 2014 paper determined that the resemblance of their shell to Amusium pleuronectes is a case of convergent evolution; thorough studies of genetics and morphology allowed for the description of Ylistrium as a new genus, being sister to Antillipecten.