Ostreoida

Cladus: Eukaryota
Supergroup: Opisthokonta
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Protostomia
Cladus: Spiralia
Cladus: Lophotrochozoa
Phylum: Mollusca
Classis: Bivalvia
Subclassis: Pteriomorphia
Ordo: Ostreoida
Subordines: Ostreina - Pectinina

References

Ostreoida Report on ITIS