Ischyodus

Ischyodus is an extinct genus of cartilaginous fish belonging to the subclass Holocephali, which includes the modern-day chimaeras.

Ischyodus was virtually identical to the present-day chimaera Chimaera monstrosa, which is found in the Atlantic Ocean and Mediterranean Sea. Just like C. monstrosa, Ischyodus had large eyes, a long whip-like tail, small lips, large pectoral fins and dorsal fin, and a poisonous dorsal spike attached to the front of the dorsal fin. The spike probably served as a method of protection against predators.

Dental plates have been found at several sites in North Dakota.

Species

 * Ischyodus bifurcatus
 * Ischyodus brevirostris
 * Ischyodus dolloi
 * Ischyodus gubkini
 * Ischyodus incisus
 * Ischyodus latus
 * Ischyodus lonzeensis
 * Ischyodus minor
 * Ischyodus mortoni
 * Ischyodus planus
 * Ischyodus rayhassi
 * Ischyodus thurmanni
 * Ischyodus townsendi
 * Ischyodus williamsae
 * Ischyodus yanshini
 * Ischyodus zinsmeisteri