Species: Somniosus microcephalus, Greenland Shark, Large Sleeper Shark

Somniosus microcephalus (Bloch & Schneider, 1801)

Greenland Shark, Large Sleeper Shark

Body cylindrical, heavy; head short (snout to pectorals 23% TL); snout short, rounded, without barbels; eyes on side of head, without nictitating membranes; spiracles large, just behind eyes; mouth short, nearly transverse; top teeth narrow, needle-like, with a single cusp, non-overlapping, 35-39 rows; bottom teeth blades, overlapping, with low, broad, strongly oblique cusps, 45-57 rows; gill slits 5, all before pectoral fin; 2 dorsal fins without spines, equal sized, low; origin of 1st dorsal in middle of back, insertion slightly closer to pelvics than to pectorals; no anal fin; pelvic fins ~equal to or larger than 2nd dorsal; tail base short (distance between 2nd dorsal base and upper tail fin origin < 2X 2nd dorsal fin base); tail fin strongly asymmetrical, paddle shaped, lower lobe long, moderately large; no keels before base of tail fin; flank denticles with erect narrow crowns and hooked points.

Mid-grey to brown; sometimes with dark bars & small light and dark spots and blotches.

Reaches 640 cm, possibly 730 cm.

Depth range 0 - 2992 m.

Benthopelagic

North Atlantic; Canada to the Gulf of Mexico.

Note: recent records off Belize and Colombia likely are this species.