Isistius brasiliensis

Common Name

Cookiecutter Shark

Year Described

Quoy and Gaimard, 1824

Identification

Teeth: 30-37 upper, 25-32 lower. Upper teeth minute and slender. Lower teeth relatively huge and triangular.

Body elongate, cylindrical and tapering posteriorly. Head small. Snout short and blunt. Nostrils under snout. Mouth with upper labial furrows, long post-oral grooves, and thick fringed lips. Jaws moderate, not as wide as head, and with lower jaw not prominent. Eyes large. Five gill slits short. Two dorsal fins close together (space less than base of either fin) and lacking spines. First dorsal fin placed far back (above pelvic fin). Second dorsal fin about same size as first. Pectoral fin very small and rounded. Pelvic fin well posterior (under rear of first dorsal fin) and smaller than either dorsal fin. Anal fin absent. Caudal fin with a well developed subterminal notch and a strong lower lobe. Skin rough and close set. Denticles square with square depressions in center.

Color

Body medium brown grading to pale below. Prominent dark brown collar on neck. Area around mouth paler brown. Fins slightly darker brown with pale margins. Eyes green. Apparently bioluminescent.

Size

Maximum size to 56cm TL (females). Adults common to 40cm TL with males being smaller in size.

Habitat

Pelagic from 0-550m over much deeper water. Appears to be solitary and vertically migrating. Takes large bites of flesh from much larger marine animals.

Range

Taken off the Bahamas, in the Gulf of Mexico and off Brazil. Apparently absent from the eastern coast of the U.S.

References

Castro, J.I. 2011. The Sharks of North America. Oxford University Press, 640 pp.