Key to the genera of Delphinidae in Korea

1 Dorsal fin absent............................................................................. Lissodelphis

- Dorsal fin present..................................................................................... 2

2 Blunt head, no prominent beak........................................................................... 3

- Long head, beak present................................................................................ 8

3 Upper teeth absent; 3–7 lower teeth on each side of jaws (maybe absent or extensively worn); forehead with deep vertical crease........................................................................................ Grampus

- Upper and lower teeth present............................................................................ 4

4 Flipper broad, paddle-shaped, rounded tip; dorsal fin pointed, tall, erected; female 0.9 m in length, male 1.8 m in length; striking black and white coloration..................................................................... Orcinus

- Dorsal fin pointed, <0.8 m .............................................................................. 5

5 Dorsal fin with broad base, located on anterior 1/3 body; dorsal fin low and falcate; bulbous head; long sickle-shaped flippers.......................................................................................... Globicephala

- Dorsal fin located on central body........................................................................ 6

6 Elbow-shaped flipper; prominent hump; lips black................................................... Pseudorca

- Flipper slightly rounded; no hump; lips white............................................................... 7

7 Teeth <15 each side (8–10 upper jaw, 10–13 lower jaw).................................................. Feresa

- Teeth>15 each side (20–26 upper jaw, 22–25 lower jaw).......................................... Peponocephala

8 Beak smoothly joins forehead........................................................................ Steno

- Beak with sharp crease where joins forehead................................................................ 9

9 Dark lateral striped from face to anus........................................................... Lagenodelphis

- Lateral striped absent or not continued from face to anus..................................................... 10

10 Discrete, short beak <3% body length; large pale gray bifurcated patches from forehead to tail............ Lagenorhynchus

- Distinct beak>3% body length.......................................................................... 11

11 Teeth>39 each tooth row.............................................................................. 12

- Teeth 18–29 on each tooth row; sharp crease where beak joins forehead.................................... Tursiops

12 Hourglass pattern present on each side.............................................................. Delphinus

- Hourglass pattern on each side absent................................................................ Stenella