Isistius plutodus

Common Name

Largetooth Cookiecutter Shark

Year Described

Garrick and Springer, 1964

Identification

Teeth: 21-28 upper, 17-19 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 relatively large, as wide as head, and with lower jaw teeth 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 slightly larger than 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 with close set square denticles.

Color

Body medium brown with either a faint dark collar or collar absent. Area around mouth paler brown. Fins slightly darker brown with pale margins. Eyes green.

Size

Maximum size to 42cm TL. Mature around 34cm TL.

Habitat

Pelagic from 60-200m over much deeper water. Appears to be solitary and vertically migrating. Takes large bites of flesh from much larger marine animals.

Range

Known only from the Gulf of Mexico and off Brazil.

References

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

Ebert, D. A., & M. Dando. 2020. Field Guide to Sharks, Rays & Chimaeras of Europe and the Mediterranean. Princeton University Press. 2020.