EX B4 ANSWERS – DICHOTOMOUS KEY

SHARKS GALORE !

1. shape of body / number of gill slits / position of mouth / shape of caudal fins / length or number of dorsal fins / presence or absence of pelvic fins / anal fins / shape of head

2. (a) Shark 4 – Fin asymmetrical in shape

Shark 7 – Top half of caudal fin same shape & size as bottom half (symmetrical)

(b) Shark 4 – Presence of anal fin

Shark 8 – Absence of anal fin

(c) Shark 5 – has 5 gill slits

Shark 12 – has 6 gill slits

Identification of Sharks

1. Family Rajidae

2. Alopiidae

3. Pristiophoridae

4. Carcharhinidae

5. Scyliorhinidae

6. Rhincodontidae

7. Isuridae

8. Squalidae

9. Dasyatidae

10. Mitsukurinidae

11. Pseudotriakidae

12. Hexanchidae

13. Sphyrnidae

14. Mobulidae