Dichotomous Key/Selachimorpha

1

 * Anal fin
 * Present -
 * Not present -

2

 * Dorsal fins
 * One - ../Hexanchiformes/
 * Two -

3

 * Body shape
 * Flattened - ../Squatiniformes/
 * Fusiform -

4

 * Snout length
 * Short - ../Squaliformes/
 * Long - ../Pristiophoriformes/

5

 * Fin spines
 * Present - ../Heterodontiformes/
 * Not present -

6

 * Mouth position
 * In front of eyes - ../Orectolobiformes/
 * Behind eyes -

7

 * Nictitating membrane
 * Present - ../Carcharhiniformes/
 * Not present - ../Lamniformes/