Japanese Angelshark

The Japanese angelshark is fairly narrow-bodied and has greatly enlarged pectoral and pelvic fins. The skin folds along the sides of the head lack distinct lobes. The eyes are oval and widely spaced; closely behind are crescent-shaped spiracles with large, boxy projections inside their anterior rims. Each nostril is large and preceded by a small flap of skin bearing two barbels; the outer barbel is thin, while the inner barbel has a spoon-like tip and a smooth to slightly fringed flange at the base. The wide mouth 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 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 300 m (980 ft). It is a bottom-dweller found over sandy bottoms, often close to rocky reefs.

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 the developing embryos are nourished by yolk. Litters of two to ten pups are birthed in spring and summer, with the newborns measuring 22 cm (8.7 in) long. Females mature sexually at 80 cm (31 in) long, while male maturation size is unknown.

The Japanese angelshark is typically inoffensive towards humans, but if disturbed, can inflict a severe bite. Across much of its range, it is a frequent catch (intentional or not) in bottom trawls and probably also set nets and demersal gillnets; the meat is eaten and the rough skin is made into a type of leather called shagreen for use in wood finishing.