<==o ACANTHARIA [Actinopoda:]
|?-o ACTINELIDA [incertae sedis]
| |--o ACTINELINA
| | `-- Astrolophidae
| `--o ACTINASTRINA
| |-- Trizonidae
| `-- Actinastridae
|--o HOLACANTHIDA
| |-- Acanthochiasmidae
| `-- Acanthoplegmatidae
|--o SYMPHYACANTHIDA
| |-- Astrolithiidae
| |-- Amphilithiidae
| `-- Pseudolithiidae
|--o CHAUNACANTHIDA
| |-- Conacontidae
| |-- Gigartacontidae
| `-- Stauracontidae
`--o ARTHRACANTHIDA
|--o SPHENACANTHINA
| |-- Acanthometridae
| |-- Lithopteratidae
| |-- Dorataspididae
| |-- Hexalaspitidae
| |-- Diplocontidae
| `-- Phractopeltatidae
`--o PHYLLACANTHINA
|-- Phyllostauritidae
|-- Stauracanthitidae
`-- Dichyacanthitidae
Reference(s):
Parker, S. P. (ed.), 1982: Synopsis and classification of living organisms. Vols. 1 & 2
–McGrew-Hill Book Company