What is "neopycnodonte"

Neopycnodonte is a genus of marine bivalve mollusks belonging to the family Gryphaeidae.

This genus is very well represented in the fossil record, however the number of living species is very few. We know fossil specimens of Neopycnodonte species dating about 60 million years. Extant species have been recorded as fossils from the Miocene to the Quaternary (from 20.43to 0.012 Ma).