"Heterococcoliths"
   "Placoliths"
     Order †Podorhabdales Rood et al. (1971)
       Family †Prediscosphaeraceae Rood, Hay & Barnard (1971)
         ?Genus †Petrarhabdus Wind & Wise, in Wise (1983)
         Genus †Prediscosphaera Vekshina (1959)