Abstract

Late Devonian conodont sequences across the Frasnian — Famennian boundary interval at two sections in cratonal Western Canada (Medicine Lake, Alberta; Trout River, Northwest Territories) are described. These are compared with isolated faunas from the epicratonal Selwyn Basin-Kechika Trough, and from allochthonous terranes of the Western Cordillera. Current conodont zonations loosely constrain the age of the boundary between Upper rhenana Zone, and the undifferentiated Upper triangularis — Lower crepida zones. Broad synchroneity of the ‘event horizon’ at Medicine Lake and Trout River is supported by several faunal links, but precise age assignment is precluded due to poor conodont yield and, at Trout River, the presence of a hiatus at the boundary. The appearance of Palmatolepis canadensis sp. nov. provides a particularly useful datum in the early Famennian of Western Canada. The phylogenetic relationships of the new species are discussed.