Children (9 direct children, 38 direct and indirect children):
Aglaspidida
(tree size 20)
Sidneyia
Emeraldella
Merostomoidea
(tree size 2)
Cheloniellida
(tree size 2)
Panlongia
(tree size 1)
Petalopleura
(tree size 4)
Arthroaspis
Falcatamacaris