Science Fair Project Encyclopedia
Gnathostomata
Placodermi
Chondrichthyes
Acanthodii
Osteichthyes
Gnathostomata is the group of vertebrates with jaws.
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.
For the phylogenetic tree of Gnathostomata see chordate. The traditional classes of Gnathostomata include:
- Placodermi - extinct
- Chondrichthyes (cartilagenous fish)
- Acanthodii - extinct
- Osteichthyes (or Teleostomi) (bony fish)
- subclass Sarcopterygii (lobe-finned fish)
- subclass Actinopterygii (ray-finned fish)
- Amphibia (amphibians)
- Reptilia (reptiles)
- Aves (birds)
- Mammalia (mammals)
External link
10-26-2009 08:16:03
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The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details