Fishes

• fishes- gnathostoma, the early jawed vertebrates, 410 mya, started in placoderms
• 2 categories of gnathostome fish?

  1. Chondrichthyes - cartilaginous fish
  2. Osteichthes- bony fish
• two distinct lineages of Osteichthyes - Actinopterygii and sarcopterygii