Black dogfish to the clade formed by the granular dogfish ("C. granulatum") and combtooth dogfish ("C. nigrum"). The black dogfish is a common species, with a wide but discontinuous distribution in the temperate waters of the Atlantic Ocean; its range abuts, but does not extend into, the Arctic Ocean. In the northeast, it occurs from Iceland to Sierra Leone, including the Faroe Islands, southern Norway, and the Rockall Trough and Porcupine Seabight off Ireland. In the northwest, it is found from southern Greenland and Baffin Island to Virginia, being particularly abundant in the Laurentian Channel, and may occur further south to the
Rockall sovereignty for itself. The consistent position of successive Irish Governments has been that Rockall and similar rocks and skerries have no significance for establishing legal claims to mineral rights in the adjacent seabed or to fishing rights in the surrounding seas." The origin and meaning of the islet's name "Rockall" is uncertain; the Old Norse name for the islet, "Ròcal", may contain the element "fjall", meaning "mountain". It has also been suggested that the name is from the Norse "*rok", meaning "foaming sea", and "kollr", meaning "bald head"—a word which appears in other placenames in Scandinavian-speaking areas. Another idea is