The oldest stromatoporoids

The Cambrian "stromatoporoids" possess characters both of stromatoporoids and of archaeocyatheans. The similarity with archaeocyatheans is most probably a genuine affinity, that with the stromatoporoids merely convergence. The genera Korovinella and Praeactinostroma should be regarded as members of the order Archaeosynconidae Zhuravleva, 1955. Study of the stratigraphic range and evolutionary history of old stromatoporoids shows that the true progenitors of this order were the Ordovician vesicular stromatoporoids of the family Labechiidae.