Systematics and evolution of cyathophylloidid and stauriid rugose corals (late ordovician–mid-silurian)Rugose corals attributed here to the families Cyathophylloididae and Stauriidae are common and internationally widespread in the Upper Ordovician Wenlock strata. They were formerly considered as closely related constituents of the Stauriidae. Here, based on the described, mostly type material mainly housed at palaeontological institutions of China and Estonia, as well as a few new specimens, a great many taxa of the two families are systematically