Author: (Bonnaterre, 1788)
A moderate-sized, short-and blunt-snouted shark with two almost equal-sized spineless dorsal fins, no anal fin, papillose thick lips, small slender-cusped upper teeth and very large lower teeth with erect triangular serrated cusps and distal blades, first dorsal fin on back with its origin behind the pectoral rear tips and its base closer to the pectoral base than the pelvics, and caudal fin with the ventral lobe not expanded.
Anterior nasal flaps short, not expanded into barbels; snout broadly conical, rounded, and short, length much less than distance from mouth to pectoral origins and about 1/4 of head length; gill openings moderately broad and about equally wide; lips very thick, fringed or pleated, not suctorial; teeth very different in upper and lower jaws, uppers small, with narrow, hooked, needle-shaped cusps and no cusplets, lowers very large, bladelike, interlocked, with broad, erect, triangular cusps, small distal blades, and serrated edges; tooth rows 16 to 21/17 to 20. Both dorsal fins without spines; first dorsal origin somewhat behind free rear tips of pectoral fins, first dorsal insertion well anterior to pelvic origins, eloser to pectoral bases than pelvics; second dorsal origin about over middle of pelvic bases; second dorsal fin only slightly larger than first, its base less than 1.5 times first dorsal base; pectoral fins with short, broadly rounded free rear tips, not broadly lobate or acute and elongated; caudal fin asymmetrical, not paddleshaped, upper lobe long, lower lobe very short or virtually absent, subterminal notch well-developed. No precaudal pits or lateral keels on caudal peduncle. Dermal denticles with low flat, ridged, unicuspid crowns, not pedicellate. Cloaca without a luminous gland. Colour greyish to black or blackish brown, sometimes violet with black spots.
Western North Atlantic: Georges Bank, northern Gulf of Mexico. Eastern Atlantic: S North Sea, Scotland, and Irish Atlantic Slope to Morocco, s western Mediterranean, Madeira, Azores, West Sahara to. Senegal, Ivory Coast to Cameroon. Western Indian Ocean: South Africa, southern Mozambique. Western Pacific: Japan, Australia(southern Queensland, Great Australian Bight, South West Australia), New Zealand. Central Pacific: Hawaiian Islands.
Habitat and Biology:
A common but sporadically distributed deepwater, warm-temperate and tropical shark of the outer continental and insular shelves and slopes from 37 to at least 1800 m depth, commonest below 200 m.! It occurs most frequently on or near the bottom but readily ranges well off the substrate. Its large oily liver allows it to attain neutral buoyancy, so it can move or hover above the bottom without the necessity of utilizing dynamic lift from fins and body. Catch records in the Mediterranean Sea suggest that it is primarily a solitary shark, not found in schools. Development is ovoviviparous, with litters of 10 to 16 young.
This shark is a powerful and versatile deepsea predator, equipped with huge serrated teeth and compact, heavy jaws of enormous power. It feeds primarily on deepwater bony fishes, including deepwater smelt (Argentinidae), viperfishes, scaly dragonfishes, barracudinas, greeneyes, lanternfishes, gonostomatids, cod, ling, whiting and other gadids, hake, grenadiers, deepwater scorpionfishes, bonito, gempylids, epigonids, and chaunacid anglers, but also skates, catsharks (Galeus), spiny dogfish (Squalus, Etmopterus and Centrophorus), squid, octopi, amphipods, isopods, shrimp and lobsters, and even polychaetes and siphonophores. The recorded diet is fairly representative of the bottom and midwater fauna where it occurs, but the presence of fast-swimming epipelagic fishes such as bonito may indicate either scavaging or some unknown means of ambushing or otherwise overcoming such prey. Often chunks of large fish are found in the stomach of this shark, as well as small whole fish. In the western Mediterranean bony fishes are a staple primary fare throughout the year. Sharks are consumed more commonly as secondary prey in spring and winter, but crustaceans become more important in the summer and cephalopods in the fall. Adults sharks eat more crustaceans and sharks and less cephalopods than young. For some reason male Dalatias have full stomachs more commonly than females.
Maximum to at least 159 cm, possibly to 182 cm, males adult between 77 to 121 cm, females between 117 to 159 cm, size at birth about 30 cm.
Interest to Fisheries:
In the Eastern Atlantic captured in bottom trawls and utilized for fishmeal and leather. Off Japan it is fished for human consumption and for the squalene content of its liver oil.
The synonymy for this species follow Bigelow and Schroeder (1948, 1957) and Bass, d'Aubrey and Kistnasamy (1976). Recently Shen and Ting (1972) described a new species, Dalatias tachiensis, from theWestern Pacific, but its distinguishing dental, dermal denticle, and labial characters are apparently juvenile ones of its 48 cm holotype, duplicated -in a 49 cm immature male specimen of D. licha from the Eastern Atlantic examined by me (BMNH 19188.8.131.52 from Porcupine Bank). Hence D. tachiensis is synonymized with D. licha.
Holotype: Lost. Type Locality: "Le cap Bretan".