schmied/reid©2010
Name_______________
Shark Classification Period ______
Key and Questions Student # ______
Couplets for Shark Classification Exercise Key
1 A. Body Kitelike in shape (when viewed from the top).............................Go to statement 12
B. Body not kitelike in shape (if viewed from the top)...............................Go to statement 2
2 A. Pelvic fin absent and nose sawlike..........................................................Family Pristiophoridae
B. Pelvic fin present..........................................................................................Go to statement 3
3 A. Six gill slits present......................................................................................Family Hexanchidae
B. Five gill slits present......................................................................................Go to statement 4
4 A. Only one dorsal fin......................................................................................Family Scyliorhinidae
B. Two dorsal fin.................................................................................................Go to statement 5
5 A. Mouth at front of head rather than back along underside of head.......Family Rhinocodontidae
B. Mouth back along underside of head..........................................................Go to statement 6
6 A. Head expanded on side with eyes at end of expansion........................Family Sphymidae
B. Head not expanded Go to statement 7
7 A. Top half of caudal fin exactly same size and shape as bottom half.......Family Isuridae
B. Top half of caudal fin different in size and shape than bottom half........Go to statement 8
8 A. First dorsal fin very long, almost half total length of body..............Family Pseudotriakidae
B. First dorsal fin regular length........................................................................Go to statement 9
9 A. Caudal fin very long, almost as long as entire body...............................Family Alopiidae
B. Caudal fin regular length...............................................................................Go to statement 10
10 A. A long needlelike point on end of nose............................................Family Scaporhynchidae
B. Nose without long point...............................................................................Go to statement 11
11 A. Anal fin absent...........................................................................................Family Squalidae
B. Anal fin present......................................................................................Family Carcharhinidae
12 A. Small dorsal fin present near tip of tail..................................................Family Rajidae
B. No dorsal fin present near tip of tail...........................................................Go to statement 13
13 A. Front of animal with two hornlike appendages...................................Family Mobulidae
B. No hornlike appendages...........................................................................Family Dasyatidae
Classification Questions: 1. What is a biological key and how is it used?
2. List four different characteristics or traits that were used in the shark key.
3. What main trait could be used to separate shark 4 from shark 8?
4. What main trait could be used to separate shark 4 from shark 7?
5. What main trait could be used to separate shark 5 from shark 12?
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