†Radiolus (sea urchin)
Parent taxon: Echinoidea according to J. J. Sepkoski 2002
Sister taxa: Acrosalenioida, Archaeocidaridae, Bromidechinus, Cassiduloidea, Cidarites, Cidaroidea, Diplocidaroida, Disasteroida, Dysaster, Echinocrinus, Echinoida, Euechinoidea, Gnathostomata, Hemicidaroidea, Oligopygoida, Parechinus, Perischoechinoidea, Regularia, Temnopleuroida
Subtaxa: none
Ecology: epifaunal grazer-deposit feeder