What is "cantharidinae"

The Cantharidinae are a taxonomic subfamily of very small to large sea snails, marine gastropod molluscs in the family Trochidae, common name top snails.

Originally it was ranked as tribe of the Trochinae, according to the taxonomy of the Gastropoda by Bouchet & Rocroi from 2005, but was elevated to the rank of subfamily following Williams et al.