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Characteristics, distribution and ecology
Taxonomische classification
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Author: (Gilbert, 1898)

Field Marks:
A slender requiem shark, with a very long, conical snout and very large, close-set nostrils, these separated by a space only slightly greater than the nostril width, a black spot outlined with white on the dorsal snout tip; form otherwise like that of the grey sharks, Carcharhinus species (especially C. acronotus, see remarks above).

Diagnostic Features:
Body rather slender. Head very narrow, conical and only slightly depressed, not trowelshaped; snout narrowly pointed in dorsoventral view, very long, with preoral length greater than internarial space and mouth width; eyes fairly large, without notches; spiracles absent; no papillose gillrakers on internal gill openings; nostrils very large, close-spaced and nearly transverse, internarial space about 1.1 to 1.3 times the nostril width; anterior nasal flaps vestigial, not tubular; labial furrows very short, uppers shorter than lowers and falling far behind eyes; teeth differentiated in upper and lower jaws; upper anteroposteriors with fairly broad semierect to oblique cusps, distal blades and serrations but no cusplets; lowers with slender, narrow, semierect cusps, blades and serrations but no cusplets; lower teeth not prominently protruding when mouth is closed; 27 to 30/24 to 28 (usually 28/25 to 27) rows of teeth. Interdorsal ridge absent; no dermal keels present on caudal peduncle; upper precaudal pit transverse and crescentic. First dorsal origin over pectoral inner margins, its midbase somewhat closer to pectoral bases than pelvic, and its free rear tip slightly anterior to pelvic origins; second dorsal fin much smaller than first, its height less than 1/3 of first dorsal height; its origin over or slightly anterior to anal insertion; pectoral fins moderately broad and triangular, slightly falcate, pectoral length from origin to free rear tip about 3/4 of pectoral anterior margin; pectoral origins under third gill slit or interspace between third and fourth gill slits; anal slightly larger than second dorsal, with short preanal ridges and a deeply notched posterior margin. Colour light grey or brownish grey above, without a colour pattern. Moderately large sharks, adults not exceeding 1.6 m.

Geographical Distribution:
Eastern Pacific: Baja California and Gulf of California, Mexico to Peru.

Habitat and Biology:
A little-known but relatively common inshore and offshore tropical shark of the continental shelves, usually found at depths of 15 to 24 m or less, but occasionally down to 192 m depth. Viviparous, with a yolksac placenta; 5 young in a litter. Feeds on small bony fishes, including anchovies and crabs. Not known to have attacked people.

Size:
Maximum at least 150 cm; males immature at 92 to 106 cm but adult at 140 cm; size at birth about 53 cm.

Interest to Fisheries:
Locally common and caught with longlines and no doubt other gear; utilized fresh or fresh frozen for human consumption and for fishmeal.

Type material:
Holotype: Stanford University Natural History Museum, SU 11893, 1200 mm immature female. Type Locality: Pacific Panama.

Whitenose shark (Nasolamia velox)