Genus
Retzia King, 1850
Luokittelu
| Organism group | Biota |
| Kingdom | Animalia |
| Phylum | Brachiopoda |
| Subphylum | Rhynchonelliformea |
| Class | Rhynchonellata |
| Order | Athyridida |
| Suborder | Retziidina |
| Family | Retziidae |
| Genus | Retzia |
| Organism group | Biota |
| Kingdom | Animalia |
| Phylum | Brachiopoda |
| Subphylum | Rhynchonelliformea |
| Class | Rhynchonellata |
| Order | Athyridida |
| Suborder | Retziidina |
| Family | Retziidae |
| Genus | Retzia |