Indo-West Pacific: South Africa and southern Arabian Sea to Indonesia, Japan, Australia, New Caledonia and New Zealand. Eastern Atlantic: Norway to South Africa, Mediterranean. Oceanic and circumglobal in temperate and tropical waters (probably the widest ranging chondrichthyian): Western Atlantic: Newfoundland to Argentina.
Large sharks, adults possibly reaching 4 m or more. Colour intense deep blue above, whitebelow, without a colour pattern. First dorsal origin well behind pectoral rear tips, its midbase much closer to pelvic than to pectoral bases, and free rear tip slightly anterior to pelvic origins second dorsal fin much smaller than first, its height 1/2 of first dorsal height or less its origin slightly posterior to anal insertion pectoral fins very narrow and somewhat falcate, pectoral length from origin to free rear tip 1/2 or less of pectoral anterior margin pectoral origins varying from under interspace between third and fourth gill slits to under fourth gill slits anal slightly larger than second dorsal, with slRort preanal ridges and a deeply notched posterior margin.
Interdorsal ridge absent low dermal keels present on caudal peduncle upper precaudal pit transverse and crescentic. Head narrow, only moderately depressed, not trowel-shaped snout narrowly parabolic in dorsoventral view, very long, with preoral length greater than internarial space and mouth width eyes large, without posterior notches spiracles absent unique papillose gillrakers present on internal gill openings nostrils small, internarial space about 2.5 to 3 times the nostril width anterior nasal flaps very short and broadly triangular, not tubular labial furrows very short with uppers shorter than lowers and with their ends falling far behind eyes teeth well differentiated in upper and lower jaws upper and anteroposteriors with broad, triangular, curved erect to oblique, serrated cusps but with no blades or cusplets (except in very young specimens) lowers with slender cusps, no blades or cusplets, and variable serrations cusps of lower teeth not prominently protruding when mouth is closed 24 to 31/25 to 34 rows of teeth. Dorsal coloration dark blue, bright blue on sides and abruptly white on the undersides, usually slender body, long snout, large eyes, gillraker papillae, long, narrow, pointed pectoral fins, short labial furrows, first dorsal fin on back but closer to the pelvic bases than the pectorals, second dorsal less than a third size of first, a weak keel on the caudal peduncle, and a narrow- lobed caudal fin with a long ventral lobe.īody rather slender.
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