Gnathostomata

Gnathostomata is the group of vertebrates with jaws.

Gnathostomata Temporal range: Ordovician - Recent
Megalodon jaws
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Subphylum:	Vertebrata
Infraphylum:	Gnathostomata

The group was meant to include all jawed fish, but in modern fashion it also includes all the tetrapods as well, since they evolved from jawed fish. It is the sister group of the Agnatha, the jawless vertebrates.

The Gnathostomata first appeared in the Ordovician period and became diverse in the Devonian period, the 'Age of Fishes'. Land vertebrates appeared in the Carboniferous period.

Subgroups

• Chondrichthyes cartilaginous fish
• Acanthodii† 'spiny sharks'
• Placoderms† armoured fish
• Osteichthyes bony fish
  • Actinopterygii ray-finned fish
  • Sarcopterygii lobe-finned fish and land vertebrates (tetrapods)