Lancetfish

Lancetfishes are large oceanic predatory fishes in the genus Alepisaurus ("scaleless lizard") in the monogeneric family Alepisauridae. Lancetfishes grow up to in length. Very little is known about their biology, though they are widely distributed in all oceans, except the polar seas. Specimens have been recorded as far north as Greenland. They are often caught as bycatch by vessels long-lining for tuna. The generic name is from Greek a- meaning "without", meaning "scale", and sauros meaning "lizard". The two currently recognized extant species in this genus are: Alepisaurus brevirostris Gibbs, 1960 (short-snouted lancetfish) Alepisaurus ferox R. T. Lowe, 1833 (long-snouted lancetfish) The anatomic difference between the two species is the shape of the snout, which is long and pointed in A. ferox, and slightly shorter in A. brevirostris. The long-snouted lancetfish is found in the tropical and northern sub-tropical waters of the Pacific ocean. The short-snouted lancetfish lives in the Atlantic ocean's tropics, subtropics, and southern sub-tropics of the Pacific ocean. A third recognized species, A. paronai D'Erasmo, 1923, is a fossil known from Middle Miocene-aged strata from Italy. Lancetfish possess a long and very high dorsal fin, soft-rayed from end to end, with an adipose fin behind it. The dorsal fin has 41 to 44 rays and occupies the greater length of the back. This fin is rounded in outline, about twice as high as the fish is deep, and can be depressed into a groove along the back. The body is slender, flattened from side to side, deepest at the gill covers, and tapers back to a slender caudal peduncle. The mouth is wide, gaping to the back of the eye, and each jaw has two or three large, fang-like teeth, in addition to numerous smaller teeth. The caudal fin is very deeply forked; its upper lobe is prolonged as a long filament, although most lancetfishes seem to lose this when captured. The anal fin originates under the last dorsal ray, and is deeply concave in outline.