Tortodus dodoensis, a new conodont species, and a Givetian (Middle Devonian) conodont fauna from the northern Mackenzie Mountains, northwest Canada

A new conodont species Tortodus dodoensis sp. nov. from the lower part of the Givetian (Middle Devonian) of the Mackenzie Mountains (NW Canada) is described. This paper also reports the lowest stratigraphic occurrence of a Givetian fauna containing a.o. Polygnathus amphora, P. denisbriceae, P. xylus ensensis, P. pseudoeiflius, P. linguiformis klapperi s.l ., P. l. weddigei, P. parawebbi and P. pseudofoliatus from the northern Mackenzie Mountains. This fauna situates the sample in the timorensis to ansatus zones interval, possibly restricting it to the timorensis Zone. This result allows the positioning of the Eifelian–Givetian contact within the lowest 7.5 m of the Hare Indian Formation (Horn River Group) (northern Mackenzie Mountains, NW Territories).