Key to families of Mysticeti in Korea

1 Dorsal fin absent; rostrum strongly arched in side; rostrum base slightly wider than tip....................... Balaenidae

- Dorsal fin (or dorsal humps) present; rostrum flat or slightly arched.............................................. 2

2 Rostrum flat; nasals reduced; frontals slightly or not visible on vertex................................ Balaenopteridae

- Rostrum slightly arched; nasals large; frontals exposed on vertex..................................... Eschrichtiidae