Conodonts found in six samples from the lower part of the Taliin Bogd Formation at the Bor hairhan uul section of South Mongolia, indicate that the lower part of the Taliin Bogd Formation is of middle Lochkovian (Early Devonian) to middle Eifelian (Middle Devonian). The conodonts from the Taliin Bogd Formation are more similar to those of North America than those of Europe. This fauna could be a cooler-water one. A new species Steptotaxis mongolianus sp. nov. is described in this paper.