Key to the Common Genera of Neogene Fossil Shark Teeth

How to Use this Key:

  1. Start with the first question. Decide whether the statment in the first box (1a) or the the second box (1b) best describes the characteristics of the fossil tooth you are trying to identify. (See this page for pictures and a glossary of shark tooth terms if you need help.)
  2. Click on the link in the row that best matches your tooth. Your choice will lead you to the next appropriate pair of questions.
  3. Work through the questions, each time choosing the characteristic that best matches your tooth from the two choices. This will lead you to the final choice which identifies the species the tooth is likely from.
1a) teeth labio-lingually flattened Go to question 2
1b) teeth short, not labio-lingually flattened Go to question 48

2a) teeth single cusped (includes teeth with lateral denticle) Go to question 3
2b) teeth multicusped Go to question 26

3a) cutting edges of teeth notched (angular) on one or both edges Go to question 4
3b) cutting edges of teeth not notched Go to question 9

4a) cutting edges of teeth partially or completely serrated Go to question 5
4b) cutting edges of teeth smooth Go to question 12

5a) one cutting edge of tooth with angular notch Go to question 6
5b) both cutting edges of tooth with angular notches Go to question 29

6a) angular notch deep Go to question 7
6b) angular notch shallow Go to question 35

7a) shoulder with fine to coarse serrations Go to question 8
7b) shoulder with weak to very fine serrations Sphyrna (in part), Carcharhinus (in part), Rhizoprionodon (in part)

8a) basal margin of root strongly arcuate, transverse groove not well developed or absent Galeocerdo (in part)
8b) basal margin of root straight to subangular with well developed transverse groove Go to question 15

9a) cutting edges of teeth are serrated Go to question 10
9b) cutting edges of teeth are smooth Go to question 16

10a) root does not protrude lingually at midline of tooth; labial face of root without valley Go to question 11
10b) root protrudes lingually (may be slight) at midline of tooth; labial face of root with valley Go to question 45

11a) teeth greater than 1" (2.54 cm.) in height; coarse serrations, thick root Carcharodon
11b) teeth 1" or less in height; basal margin of enamel of lingual face is root not massive Carcharhinus longimanus (upper teeth)

12a) one cutting edge of tooth with angular notch Go to question 13
12b) both cutting edges of tooth with angular notches Go to question 20

13a) crown contorted Galeocerdo (in part)
13b) crown not contorted Go to question 14

14a) enamel shoulder with faint to coarse serrations Galeorhinus, Paragaleus (in part), Rhizoprionodon (in part), Carcharhinus (in part)
14b) enamel shoulder smooth Go to question 21

15a) teeth much higher than wide Prionace (in part)
15b) teeth nearly equilateral Go to question 39

16a) teeth have lateral cusplets Go to question 17
16b) teeth do not have lateral cusplets Go to question 22

17a) number of lateral cusplets on each side of crown equal Go to question 18
17b) number of lateral cusplets on each side of crown unequal Go to question 24

18a) lateral cusplets adjacent to basal edge of crown; cutting edge of crown complete Go to question 19
18b) lateral cusplets well above basal margin of crown; cutting edge of crown incomplete Hemipristis serra (in part, lower anterior)

19a) transverse groove absent; cutting edges usually straight and never parallel toward apex Lamna
19b) transverse groove present; cutting edges usually concave and in more anterior teeth nearly parallel toward apex Go to question 33

20a) root protrudes on lingual side; central foramen in shallow groove Negaprion brevirostris (in part)
20b) root does not protrude on lingual side; central foramen in deep transverse groove Carcharhinus (in part)

21a) cutting edge extends to base of crown Rhizoprionodon (in part), Sphyrna (in part)
21b) cutting edge does not extend to base of crown Prionace (lower teeth)

22a) transverse groove present Go to question 23
22b) transverse groove absent or incipient Go to question 28

23a) asymmetrical teeth; transverse groove does not extend to basal margin of root Alopias (in part)
23b) nearly symmetrical teeth; transverse groove extends to basal margin of root to form a notch Carcharhinus (lower teeth)

24a) main portion of crown recumbent Echinorhinus
24b) main portion of crown not recumbent Go to question 25

25a) root not lobate Go to question 47
25b) root lobate Go to question 46

26a) mesial edge of main cusp serrated, cusplets decline regularly in size distally Go to question 27
26b) mesial edge of main cusp with one or more denticles, cusplet distal to main cusp shorter than more distal cusplets Heptranchias

27a) 3 to 4 cusplets, serrations recurved Notorynchus (in part)
27b) 7 to 10 cusplets, serrations not recurved Hexanchus (in part)

28a) central foramen present; lingual face of root smooth Go to question 32
28b) central foramen absent; lingual face of root striated Hexanchus (upper anterior teeth)

29a) cutting edges of crown smooth; enamel shoulders weakly to finely serrated Go to question 30
29b) cutting edges of crown partially or completely serrated Go to question 31

30a) transverse groove shallow or absent Negaprion brevirostris (in part)
30b) transverse groove deep Carcharhinus (in part)

31a) lingual face of root convex Carcharhinus (in part)
31b) lingual face of root flattened Sphyrna (in part)

32a) root lobes round and extend beyond basal limit of crown Alopias (in part)
32b) root lobes not round (in teeth under 1.5" in height) and don't extend noticeably beyond basal limit of crown Isurus

33a) lateral cusplets prominent, not strongly curved Go to question 34
33b) lateral cusplets not prominent, strongly curved Carcharias taurus

34a) two or more pairs of lateral cusplets, root lobes deeply arched and narrow Odontaspis ferox
34b) one pair of long lateral cusplets, root lobes moderately arched and broad Odontaspis noronhai

35a) relatively narrow cusps Go to question 36
35b) broad cusps Go to question 37

36a) mesial cutting edge concave with slightly coarser serrations on both shoulders Carcharhinus limbatus
36b) mesial and distal cutting edges of cusps essentially straight Go to question 46

37a) cusps with slightly coarser serrations distally Go to question 38
37b) cusps with uniform serrations Carcharhinus altimus

38a) mesial cutting edge marked by noticeable gap in serrations Carcharhinus falciformis (upper anteriors)
38b) mesial cutting edge not marked by noticeable gap in serrations Carcharhinus falciformis (upper laterals)

39a) cusps narrow Go to question 40
39b) cusps moderately broad Carcharhinus brachyurus

40a) cusps uniformly serrated with fine serrations Sphyrna (in part) & Carcharhinus (in part)
40b) cusps not uniformly serrated Go to question 41

41a) saw-toothed serrations on distal enamel shoulder Go to question 42
41b) fine serrations on distal enamel shoulder Carcharhinus acronotus

42a) mesial serrations fine Go to question 44
42b) mesial serrations coarse basally Go to question 42

43a) contact between root and labial side of crown V-shaped Carcharhinus leucas
43b) contact between root and labial side of crown flat and wide Carcharhinus obscurus

44a) mesial cutting edge essentially straight Carcharhinus porosus
44b) mesial cutting edge noticeably concave basally Carcharhinus perezi

45a) transverse groove present in lingual root protrusion Hemipristis serra (in part)
45b) transverse groove absent in lingual root protrusion; teeth greater than 1" (2.54 cm); basal margin of enamel of lingual face is gently arched to straight in small teeth and becoming strongly arched in larger specimens Carcharocles

46a) basal margin of root broadly arched Alopias (in part)
46b) basal margin of root not broadly arched Hemipristis serra (in part)

47a) mesial cutting edge forms shoulder with one or more cusplets Notorynchus (in part)
47b) mesial cutting edge without shoulder and cusplets Hexanchus (in part)

48a) single long sharp cusp Squatina
48b) small center cusp with 3-4 cusplets on either side Ginglymostoma