Order Clypeasteroida Agassiz 1836 (sand dollar)
PaleoDB taxon number: 33109
Full reference: L. Agassiz. 1836. Prodrome d'une monographie des radiaires ou échinodermes. Mémoires de la Société des Sciences Naturelles de Neuchâtel 1:168-199
Parent taxon: Neognathostomata according to A. Kroh and A. B. Smith 2010
Sister taxa: Apatopygidae, Archiaciidae, Bothryopneustes, Cassiduloida, Clypeidae, Clypeolampadidae, Echinolampadoida, Nucleolitidae, Pygaulidae
Subtaxa: Clypeasterina, Conoclypeidae, Faujasiidae, Hesperaster, Laganina, Oligopygidae, Plesiolampadidae, Proescutella, Prowillungaster, Rotulina, Runa, Scutellina, Tournoueraster, Willungaster
Ecology: slow-moving semi-infaunal detritivore