Kitefin Shark

The kitefin shark has a moderately elongated body with a very short, rounded snout. The eyes and spiracles are large. The lips are thick with pleats or fringes, though are not modified to be suctorial. There are 16–21 tooth rows in the upper jaw and 17–20 tooth rows in the lower jaw. The upper teeth are small and spike-shaped, curving slightly towards the corners of the mouth. The lower teeth are very large, knife-shaped, and serrated, with their bases interlocking to form a continuous cutting surface. The first dorsal fin is slightly smaller and shorter-based than the second, and neither has spines. The first dorsal fin originates behind the free rear tip of the pectoral fins, while the second originates above the middle of the pelvic fin bases. The pectoral fins are short and rounded. The caudal fin has a prominent upper lobe with a well-developed notch near the tip, and a barely present lower lobe. The form and arrangement of the fins is similar to the Portuguese dogfish (Centroscymnus coelolepis), from which this species can be distinguished by the lack of fin spines. The dermal denticles are small and flat, with a single horizontal ridge ending in a point. The coloration is a uniform dark brown or gray, sometimes with faint black spots on the back. The fins have white or translucent trailing edges, and the tip of the caudal fin is black. …

The kitefin shark has an almost circumglobal range in tropical and warm-temperature waters, consisting of a number of widely separated populations with likely little interchange between them. This shark has not been reported from the eastern Pacific and northern Indian Oceans. In the northern Atlantic, it occurs in the Georges Bank and the northern Gulf of Mexico, and from the North Sea to Cameroon, including around the British Isles, in the western and central Mediterranean Sea, and off Madeira and the Azores. In the Indian Ocean, it is found off South Africa and Mozambique. In the Pacific, it occurs off Japan, Java, Australia and New Zealand, and the Hawaiian Islands. There is a single record of this species in the southern Atlantic, from off southern Brazil. An offshore, deepwater species, the kitefin shark is most common at a depth of 200–600 m (660–1,970 ft), but has been captured from the surface to as deep as 1,800 m (5,900 ft). Off the Azores this shark segregates by sex, with females most common around a depth of 230 m (750 ft) and males most common around 412–448 m (1,352–1,470 ft). The kitefin shark inhabits the outer continental shelves and upper continental slopes, and is also found around oceanic islands and seamounts. …

Relatively common where it occurs, kitefin sharks are usually solitary in nature but may form small groups. It is a slow swimmer with a large liver filled with squalene, a lipid less dense than water, allowing it to maintain neutral buoyancy and hover above the bottom with little effort. Studies off the coast of North Africa and in the Gulf of Genoa have found males outnumbering females by 2:1 and 5:1 respectively; this imbalanced sex ratio has not been observed off South Africa and may reflect sampling bias. The kitefin shark is preyed upon by larger fishes and sharks, as well as by sperm whales (Physeter macrocephalus). Parasite data on this species is limited; an examination of two sharks caught off Ireland found three nematodes in the stomach lumen. One could be identified as Anisakis simplex L3, while another may have been a larval Raphidascaris. A powerful and versatile deepwater predator, the short, robust jaws of the kitefin shark give it an enormously strong bite. …