The oldest known bryozoan: P rophyllodictya ( C ryptostomata) from the lower T remadocian ( L ower O rdovician) of L iujiachang, south‐western H ubei, central C hina

A new cryptostome bryozoan, P rophyllodictya simplex sp. nov., is described from the N antzinkuan F ormation ( L ower O rdovician, lower T remadoc) of L iujiachang, central C hina. This antedates the previously oldest known bryozoan by several million years. Colony morphology and the phylogenetic position of P rophyllodictya within C ryptostomata are explored. Phylogenetic analysis suggests that C ryptostomata (except P rophyllodictya ) can be divided into two major groups, and that P rophyllodictya occupies a basal position in the cryptostome tree, which accords with its simple morphology and antiquity. A close relationship is evident between bryozoans from the S outh C hina palaeoplate and those from B altica.