Children (18 direct children, 21 direct and indirect children):
Strongylocentrotus sachalinicus
Strongylocentrotus polyacathus
Strongylocentrotus djakonovi
Strongylocentrotus echinoides
Strongylocentrotus purpuratus
Purple sea urchin
Strongylocentrotus polyacanthus
(tree size 2)
Strongylocentrotus pallidus
Strongylocentrotus droebachiensis
Strongylocentrotus franciscanus
Strongylocentrotus pulchellus
Strongylocentrotus nudus
Strongylocentrotus intermedius
(tree size 1)
Strongylocentrotus fragilis
Strongylocentrotus antiquus
Strongylocentrotus cotteaui
Strongylocentrotus magistrus
Strongylocentrotus octoporus
Strongylocentrotus scaber