1. Subterclass Atelostomata
2. Genus Atlasaster Lambert, 1931 †
3. Family Desorellidae Lambert, 1911 †
4. Family Galeropygidae Lambert, 1911 †
5. Genus Grasia Michelin, 1854 †
6. Order Holectypoida †
7. Family Menopygidae Lambert, 1911 †
8. Genus Mesodiadema Neumayr, 1889 †
9. Subterclass Neognathostomata
10. Family Pygasteridae Lambert, 1900 †
11. Family Pygorhytidae Lambert, 1909 †
12. Suborder Amphisternata accepted as Spatangoida (subjective junior synonym)
13. Family Infraclypeidae Saucède, Mooi & David, 2007 † accepted as Desorellidae Lambert, 1911 † (junior synonym)
14. Genus Loriolella Fucini, 1904 † accepted as Mesodiadema Neumayr, 1889 † (subjective junior synonym)
15. Superorder Pileatoida † accepted as Anorthopygidae Wagner & Durham, 1966 † (type-taxon closely related to Anorthopygus and member of the Anorthopygidae)
16. Order Pourtalesioida accepted as Pourtalesiidae A. Agassiz, 1881 (Not in use)
17. Genus Pseudopygaster Hawkins, 1922 † accepted as Mesodiadema Neumayr, 1889 † (subjective junior synonym)
18. Order Pygasteroida † accepted as Pygasteridae Lambert, 1900 † (paraphyletic )
19. Superorder Microstomata
20. Family Catopygids † (temporary name)
21. Family Gitolampadids † (temporary name)
22. Family Hyboclypids † (temporary name)
23. Family Pygurids † (temporary name)

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