Species: Isistius plutodus, Largetooth Cookiecutter Shark

Isistius plutodus Garrick & Springer, 1964

Largetooth Cookiecutter Shark

Body cigar-shaped; head narrow and conical; very short bulbous snout; spiracles present, large, behind eye; eyes far forward on head; no nictitating eyelids; mouth large; lips suctorial, not fringed; teeth in upper and lower jaws different, upper - narrow, needle-like, no cusplets, 29 rows, lower - very large, triangular, not serrated, 17-19 rows; 5 gill slits, all before pectoral; both dorsal fins small, 2nd heigher, close together (space between them ~same as D1 base), very near tail fin (space between 2nd dorsal and caudal fin ~same as 2nd dorsal base), similar size; space between second dorsal and tailfin base ~equal to second dorsal base; no anal fin; pectorals rounded; pelvic fins smaller than dorsals; no lateral ridges between pectoral and pelvic fins; no pits on upper tail base; keel on tail base; tail fin short, asymmetrical, lower lobe only ~1/2 length of top lobe; terminal notch not present.

Uniform dark brown, lighter under head.

Size: 42 cm.

Habitat: Found over bottom and sometimes near surface over the slopes and trenches.

Depth: 60-200 m.

W Atlantic and NW Pacific; the Gulf of Mexico.