†Archaeocidaris M'Coy 1844 (sea urchin)
Full reference: F. M'Coy. 1844. A synposis of the characters of the Carboniferous limestone fossils of Ireland 1-274
Parent taxon: Archaeocidaridae according to C. L. Schneider et al. 2005
Sister taxa: Eocidaris, Lepidocidaris, Nortonechinus, Polytaxicidaris, Silurocidaris, Xenocidaris
Subtaxa: Archaeocidaris selwyni
Ecology: epifaunal grazer-deposit feeder