Gnathostomata

The group is traditionally a superclass[?], including the familiar classes of fish, birds, and so forth, and a sister group of the jawless vertebrates Agnatha. However, recent genetic studies are causing a reassessment of Gnathostomata as a grouping.

Other distinguishing characteristics of living gnathostomates are the myelin sheathes of neurons, and an adaptive immune system.

The traditional classes of Gnathostomata include:

• Placodermi[?] - extinct
• Chondrichthyes (cartilagenous fish)
• Acanthodii[?] - extinct
• Osteichthyes (bony fish)
  • subclass Sarcopterygii (lobe-finned fish)
  • subclass Actinopterygii (ray-finned fish)
• Amphibia (amphibians)
• Reptilia (reptiles)
• Aves (birds)
• Mammalia (mammals)

External link

• Tree of Life discussion of Gnathostomata (http://tolweb.org/tree?group=Gnathostomata&contgroup=Vertebrata)