The genus Hikorocodium, with the type species Hikorocodium elegantae from the Permian of Japan, was described originally as a codiacean alga by Endo. It is not a codiacean alga but an inozoid sponge of the family Preperonidellidae. Several fossils described later by Endo and other authors as H. elegantae should be assigned to different inozoid sponge taxa. Specimens of H. fertiliz, described by Endo from the Jurassic of Japan, are also sponge fragments. The taxonomic positions of H. transversum Endo and H. kuramotoi Nakamura, as sponges or algae, remain uncertain.