Parent taxon: Echinoidea according to J.O. Chiesa et al. 1995
See also Fell and Pawson 1966 and Sepkoski 2002
Sister taxa: Acrosalenioida, Archaeocidaridae, Bromidechinus, Cassiduloidea, Centrechinoida, Cidaris aculeata, Cidaris aialensis, Cidaris alpina, Cidaris alternata, Cidaris austriaca, Cidaris avena, Cidaris biconica, Cidaris biformis, Cidaris braunii, Cidaris buchii, Cidaris caudex, Cidaris cingulata, Cidaris coralliophila, Cidaris costalarensis, Cidaris costata, Cidaris costeanensis, Cidaris decorata, Cidaris decoratissima, Cidaris dorsata, Cidaris ecki, Cidaris forminensis, Cidaris fustis, Cidaris glabra, Cidaris hausmanni, Cidaris lanceata, Cidaris linearis, Cidaris milierensis, Cidaris ovata, Cidaris perplexa, Cidaris petersii, Cidaris plana, Cidaris pyramidalis, Cidaris quadrialata, Cidaris quadriserrata, Cidaris regnyi, Cidaris remifera, Cidaris remifera, Cidaris reticulata, Cidaris schwageri, Cidaris scrobiculata, Cidaris seelandica, Cidaris semicostata, Cidaris similis, Cidaris spinachristi, Cidaris spongiosa, Cidaris stipes, Cidaris stoppanii, Cidaris sulcata, Cidaris tenuicostata, Cidaris tetraedrica, Cidaris trapezoidalis, Cidaris trigona, Cidaris triserrata, Cidaris undulatus, Cidaris valparolae, Cidaris verticillata, Cidaris verticillata, Cidaris waechteri, Cidaris wissmanni, Cidaris zardini, Cidaroidea, Corystusidae, Dallonia, Diplocidaroida, Disasteroida, Echinopluteus, Euechinoidea, Exocycloida, Exocycloidea, Gajechinus, Gnathostomata, Hemicidaris gracilis, Hemicidaris obliquelineata, Oligopygoida, Ombria, Parechinus, Perischoechinoidea, Plegiocidaris senex, Pleurechinus, Proterocidaridae, Protocidaris, Radiolus, Radiolus adametzi, Radiolus alutensis, Radiolus antipai, Radiolus boletus, Radiolus complanatus, Radiolus culter, Radiolus festuca, Radiolus fusus, Radiolus herbichi, Radiolus lineola, Radiolus penna, Radiolus racadaui, Radiolus raiblianus, Radiolus rostratus, Radiolus segmentatus, Regularia, Strechoritina, Temnopleuroida, Uvanogelia, Vernius, Yunnanechinus
Subtaxa: Echinoina Spaniocyphus Trochoechinus
Ecology: slow-moving low-level epifaunal grazer
Distribution:
• Quaternary of Chile (1 collection), Japan (1)
• Miocene of Morocco (3), United States (1: Virginia)
• Oligocene to Miocene of United States (1: California)
• Paleocene of Argentina (6)
• Cretaceous of Argentina (12), Brazil (1), Bulgaria (1), Georgia (1), Hungary (1), Italy (1)
• Jurassic to Cretaceous of Antarctica (1)
• Jurassic of Canada (2: British Columbia, Nova Scotia), Germany (1), India (4), Italy (1), Poland (2), the United Kingdom (2)
• Triassic of Italy (2)
• Permian of China (1)
• Carboniferous of United States (2: New Mexico, New mexico)
Total: 48 collections each including a single occurrence