| Name | Children | Media (from resource) | Traits |
|---|---|---|---|
| Aachenaspis | 0 | 0 | 0 |
| Aachenia | 0 | 0 | 0 |
| Aachenia | 1 | 0 | 0 |
| Aachenia debeyi | 0 | 0 | 0 |
| Aacocrinus | 0 | 0 | 11 |
| Aafrita | 1 | 0 | 7 |
| Aafrita | 0 | 0 | 0 |
| Aafrita biladalshama | 0 | 0 | 7 |
| Aaglacrinus | 0 | 0 | 0 |
| Aaleniella Plumhoff 1963 | 0 | 0 | 0 |
| Aaleniella | 0 | 0 | 0 |
| Aalenirhynchia subdecorata | 0 | 0 | 0 |
| Aalenirhynchia walkeri | 0 | 0 | 0 |
| Aaptochiton | 0 | 0 | 10 |
| Aaptochiton | 1 | 0 | 9 |
