Species: Carcharhinus obscurus, Dusky Shark

Carcharhinus obscurus (Lesueur, 1818)

Dusky Shark

Body moderately slender; snout moderately short (</= mouth width), broad, rounded; eyes round, large; nasal flaps rudimentary; upper front teeth broadly triangular, low, straight at front to a little oblique at sides, serrated, not notched; lower front teeth with low, narrow, finely serrated points; first dorsal fin moderately large, front edge broadly arched, tip pointed to narrowly rounded, origin over/slightly before pectoral free rear tip; origin of second dorsal above anal fin origin, with long base and long free rear tip, fin low, usually < 2.3% (1.5-2.3%) TL; pectoral long, strongly curved rear border, pointed tip; a marked crest between dorsal fins; pelvic fin with origin only slightly behind free rear tip of 1st dorsal fin; tail base without keel; tail fin strongly asymmetrical, with well developed lower lobe, undulating ridge along dorsal surface of top lobe, and a notch under tip of that lobe.

Grey, shading to white ventrally, with a faint, near-horizontal, grey band invading the white of upper abdomen; tips of fins dusky.

Size: reaches 365 cm, possibly 400 cm.

Habitat: Inshore to offshore coastal- pelagic, primarily on continental shelves, not in low salinity habitats.

Depth: 0-573 m.

Circumglobal in tropical and warm temperate seas; the eastern United States to Guyana.

Note: Very similar in appearance and easily confused with C. galapagensis; in C obscurus the origin of the 1st dorsal fin is over/slightly behind the free rear tip of the pectoral fin (vs over the inner margin & before that tip in C galapagensis); and the pelvic origin is only slightly behind the free rear tip of the 1st dorsal fin (vs well behind in C galapagensis).