and skates, and the other containing the sharks (Figure13.9). There are eight orders of
sharks within the superorder. They are distinguished by such features as:
- Number of gill slits
- Numbers and types of fins
- Type of teeth
- Body shape
- The sawsharks, with an elongate, toothed snout used for slashing the fish that they
eat. - The bullhead sharks, with teeth used for grasping and crushing shellfish.
- Carpet sharks withbarbels
- Nocturnal habits
- The groundsharks, with an elongated snout.
- The mackerel sharks, with large jaws and ovoviviparous reproduction, where the eggs
develop inside the mother’s body after internal fertilization, and the young are born
alive.
Figure 13.9: A spotted Wobbegong shark (Orectolobus maculatus), at Shelly Beach, Sydney,
Australia, showing skin flaps around the mouth and cryptic coloration. ( 1 )
Bony Fishes
TheOsteichthyes,or bony fish, contain almost 27,000 species, which are divided into two
classes: the ray-finned fish (Actinopterygii) and the lobe finned fish (Sarcopterygii). Most