Genus
Leptagonia McCoy, 1844
Classification
| Organism group | Biota |
| Domain | Eukaryota |
| Kingdom | Animalia |
| Phylum | Brachiopoda |
| Subphylum | Rhynchonelliformea |
| Class | Strophomenata |
| Order | Strophomenida |
| Superfamily | Strophomenoidea |
| Family | Rafinesquinidae |
| Subfamily | Leptaeninae |
| Supergenus | Kiaeromena |
| Genus | Astamena |
| Estonomena | |
| Harjumena | |
| Kurnamena | |
| Lepidoleptaena | |
| Leptaena | |
| Leptaenopoma | |
| Leptagonia | |
| Oandumena | |
| Schmidtomena | |
| Similoleptaena |