Related how?

Biota (Life)
Eukaryote (Eukarya)
Podiata
Unikont (Unikonta)
Opisthokont (Opisthokonta)
Holozoa
Filozoa
Apoikozoa (Choanozoa)
Animal (Animalia)
Metazoa
Epitheliozoa
Eumetazoa
Bilateria
Deuterostome (Deuterostomia)
Echinodermata (Echinoderms)
Sea urchin (Echinoidea)
Euechinoidea
Diadematacea

Diadematoida (729975)

Children (3 direct children, 109 direct and indirect children):

Aspidodiadematidae (tree size 29)

Diadematidae (tree size 74)

Lissodiadematidae (tree size 3)