Children (8 direct children, 259 direct and indirect children):
Hemipneustidae
(tree size 6)
Holasteridae
(tree size 97)
Meridosternata
(tree size 122)
Plexechinidae
(tree size 8)
Pseudholasteridae
(tree size 13)
Stenonasteridae
(tree size 5)
Murciaster
Corculum