The spiny ogfish, spurdog, or piked dogfish, Squalus acanthias, is one of the best known of the dogfish, members of the family Squalidae in the order Squaliformes. While these common names may apply to several species, Squalus acanthias is readily distinguished by having two spines (one anterior to each dorsal fin) and its lack of an anal fin. It is found in shallow waters and offshore in most parts of the world, especially in temperate waters.