†family Oligopygidae Duncan 1889 (sand dollar)
Echinoidea - Clypeasteroida - Oligopygidae
Alternative spelling: Oligopyginae
Full reference: P. M. Duncan. 1889. A revision of the genera and great groups of the Echinoidea. Journal of the Linnean Society, Zoology 23:1-311
Parent taxon: Clypeasteroida according to A. Kroh and A. B. Smith 2010
See also Squires and Demetrion 1994 and Wagner and Durham 1966
Sister taxa: Clypeasterina, Conoclypeidae, Faujasiidae, Laganina, Plesiolampadidae, Prowillungaster, Rotulina, Runa, Scutellina, Tournoueraster, Willungaster
Subtaxa: Haimea Microlampas Oligopygus Protolampas
Type: Oligopygus
Ecology: slow-moving semi-infaunal detritivore
Distribution: