A single specimen of Arkelloceras n. sp. aff. A. mclearni (Stephanoceraticeae) is described from the Rock Creek Member of the Fernie Group, Middle Jurassic, in the Alberta foothills north of Jasper; the Rock Creek is probably entirely middle Bajocian in age. The specimen is intermediate in dimensions between A. mclearni and A. tozeri, the only known species, named and described by Frebold from islands in the Canadian Arctic. It is concluded that the Arctic species are probably also middle Bajocian in age rather than late Bajocian to early Bathonian or early Callovian, as once thought.

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