| Name | Children | Media (from resource) | Traits |
|---|---|---|---|
| Aristostomias | 0 | 0 | 1 |
| Armillaria (Honey Fungus) | 0 | 0 | 1 |
| Arthropoda (arthropods) | 216 | 0 | 0 |
| Aspisoma | 0 | 0 | 1 |
| Astronesthes | 0 | 0 | 1 |
| Atolla Haeckel 1880 | 0 | 0 | 1 |
| Augaptilus Giesbrecht 1889 | 0 | 0 | 1 |
| Aulacoctena Mortensen 1932 | 0 | 0 | 1 |
| Aulosphaera Haeckel 1860 | 0 | 0 | 1 |
| Bacteria | 5 | 0 | 0 |
| Balanoglossus | 0 | 0 | 1 |
| Barbantus | 0 | 0 | 1 |
| Bargmannia Totton 1954 | 0 | 0 | 1 |
| Bassia L. Agassiz 1862 | 0 | 0 | 1 |
| Bathochordaeus Chun 1900 | 0 | 0 | 1 |
