Wikipedia
Neotrigonia
Neotrigonia is a genus of living saltwater clams, marine bivalve mollusks in the family Trigoniidae, which otherwise consists only of fossil genera. For a long time the entire family was thought to be long extinct, but a living species that is now placed in this genus was discovered in 1802. At that time it was assigned to the fossil genus Trigonia. Currently, according to WoRMS, 8 species in this genus are recognized.