Shark Types (Orders)

There are eight types (or orders) of sharks based on common features including body and snout shape, number of gill openings, postion of the mouth, and the presence or absence of an anal fin and dorsal fin spines.

No
anal fin		 Flat body, raylike, mouth in front Squatiniformes Squatiniformes
(Angel sharks)
Not raylike Long snout,
sawlike		 Pristiophoriformes Pristiophoriformes
(Saw sharks)
Short snout,
not sawlike		 Squaliformes Squaliformes
(Dogfish sharks)
With
anal fin		 5 gill slits 2 dorsal fins Dorsal fins
without spines		 Mouth
behind
eyes		 nicitating membraneNictitating membrane (third clear eyelid) Carcharhiniformes Carcharhiniformes
(Ground sharks)
no nicitating membraneNo nictitating membrane Lamniformes Lamniformes
(Mackerel sharks)
Mouth in front of eyes Orectolobiformes Orectolobiformes
(Carpet sharks)
Dorsal fins with spines Heterodontiformes Heterodontiformes
(Bullhead sharks)
6-7 gill slits Hexanchiformes Hexanchiformes
(Frilled and cow sharks)
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