Children (6 direct children, 662 direct and indirect children):
Graptolithinia
(tree size 369)
Graptolithina
Enteropneusta
(tree size 164)
Acorn worm
Pterobranchia
(tree size 12)
Planctosphaeroidea
(tree size 2)
Graptolithida
Graptolithoidea
(tree size 109)