Heterodontiformes is an order of sharks in the superorder Galeomorphii. It includes the bullhead sharks (genus Heterodontus), and several extinct genera. The earliest known members of the group are from the Early Jurassic (Toarcian), around 175 million years ago. Several extinct genera are known from the Jurassic, with all except Paracestracion only known from isolated teeth. The oldest known members of the modern genus appeared during the Late Jurassic.[1]
| Heterodontiformes Temporal range: | |
|---|---|
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| Heterodontus japonicus | |
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| Paracestracion danieli | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Subclass: | Elasmobranchii |
| Subdivision: | Selachimorpha |
| Superorder: | Galeomorphii |
| Order: | Heterodontiformes L. S. Berg, 1940 |
| Genera | |
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Heterodontiformes are connected to multiple species that are currently known as bullhead sharks, horn sharks, port jackson sharks, and many others. Bullhead sharks are 2-5 feet long with big broad heads and pig-like snouts.[2] Their stiff spine on both of their dorsal fins and anal fins allow for easy movement. Gill slits located on the sides of their skeleton enables the sharks the ability to breathe. Bullhead sharks also have cone-shaped teeth in the front of their mouth and flat grinding molars in the back of their mouths to grind the hard shells of their food. For the sharks to be able to have a full range of vision prominent supraorbital ridges elevate the crest of the eye. The caudal fin separates the upper and lower lobes with a prominent notch. These fins are covered with large abrasive dermal denticles.
Overall Average sharks reach from 28 to 51 inches long but a few species may reach slightly longer. Young sharks stay around 40 to 150 meters and migrate to shallow water as they age.[3]
Heterodontiformes are found in shallow water in the western and eastern Pacific Ocean and the western Indian Ocean. Their eating behaviors include creatures such as starfish, sea urchins, sea cucumbers, small fish, mollusks, and crustaceans.[4] Bull Sharks tend to group together for short periods of time but, spend most of their time alone.