| belgium | | petricolaria pholadiformis | species | 1 | 0 |
| spain | | petricolaria pholadiformis | species | 1 | 0 |
| united kingdom | england | petricolaria pholadiformis | species | 5 | 0 |
| united states | florida | petricola lapicida | species | 4 | 0 |
| united states | maryland | petricolaria pholadiformis | species | 1 | 0 |
| united states | massachusetts | petricolaria pholadiformis | species | 169 | 0 |