This list of the Paleozoic life of Iowa contains the various prehistoric life-forms whose fossilized remains have been reported from within the US state of Iowa and are between 538.8 and 252.17 million years of age.
Reconstructive diagram (left) of a fossil (right) of the Ordovician sea urchin Bothriocidaris. The short spines which were attached to the tubercles are not drawn. †Bothriocidaris
†Bothriocidaris maquoketensis
†Botryocrinus
†Botryocrinus thomasi – type locality for species
†Brachythyris
†Brachythyris burlingtonensis – or unidentified comparable form
†Brachythyris chouteauensis
†Brachythyris peculiaris
†Brachytomaria
†Brachytomaria semele
†Breviphillipsia
†Brockocystis
†Brockocystis nodosaria
†Bromidella
†Bromidella depressa
†Bromidella rhomboides
†Bryantodina
†Bryantodina typicalis
†Bucanella
†Bucanella conradi
†Bucanopsis
†Bucanopsis lirata
†Bullatekka
†Bullatekka granilabiatus
†Bullatella
†Bullatella granilabiatus
Life restoration of the Early Ordovician-Silurian trilobite Bumastus †Bumastus