Mississippian colonial tabulate and rugose corals from the Flett Formation, Liard Basin, northwest Canada

Colonial Rugosa and Tabulata from the lower and middle Viséan Flett Formation of the Liard Basin (Canada) are described. Michelinia expansa is the first tabulate coral described from the Flett Formation. The new generic name Cordilleria is introduced for the North American Lithostrotionidae and its differences from the European Siphonodendron are documented. Extremely wide variability in all characters and the small size of the studied collection allowed description of numerous Liard Basin specimens in open nomenclature only. Discussion of the most important characteristics of Cordilleria gen. nov. forms an introduction to the comprehensive revision of the North American Lithostrotionidae. The state of preservation of a colony identified as Stelechophyllum cf. banffense emphasizes the necessity of recognizing the diagenetic alterations of specimens prior to their taxonomic identification