is terminally placed and has furrows at the corners. There are 10 tooth rows on either side of both jaws, separated by a gap in the middle; the teeth are small, narrow, and pointed. There are five pairs of gill slits located on the sides of the head. The frontmost portion of each pectoral fin forms a triangular lobe separate from the head. The outer corners of the pectoral fins are angular, and their rear tips are rounded. The pelvic fins have convex margins. The two angular dorsal fins are similar in shape and size, and are located behind the pelvic fins. The caudal peduncle is flattened with a keel running along either side, and supports a roughly triangular caudal fin with rounded corners. The lower lobe of the caudal fin is larger than the upper. The dorsal surface is covered by medium-sized dermal denticles, and a distinctive row of large thorns is present along the midline of the back and tail. This species is light to dark brown above with a dense covering of squarish dark spots, which become finer on the fins. The underside is white with darker mottling. Various sources give differing maximum lengths, ranging from . Distribution and habitat The Japanese angelshark is native to the cooler waters of the northwestern Pacific; its range extends from the eastern coast of Honshu, Japan, to Taiwan, and includes the southern Sea of Japan, the Yellow Sea, the East China Sea, and the Taiwan Strait. Some older sources reported it may occur in the Philippines, but recent research suggests the only angel shark species in that area is S. caillieti. The Japanese angelshark inhabits the continental shelf, usually in the shallows, but also to as deep as . It is a bottom-dweller found over sandy bottoms, often close to rocky reefs. Biology and ecology During the day, the Japanese angelshark mostly lies partly buried on the bottom; its complex color pattern provides camouflage as it ambushes nearby prey. At night, this species becomes more active. Its diet consists of demersal fishes, cephalopods, and crustaceans. It may be found alone or in proximity to others of its species. Parasites documented from this species include the tapeworms Phyliobothrium marginatum and Tylocephalum squatinae, the copepods Eudactylina squatini and Trebius shiinoi, and the praniza larvae of the isopod Gnathia trimaculata. The Japanese angelshark is viviparous, and as in other members of its family