Fish do not represent a monophyletic group, and therefore the "evolution of fish" is not studied as a single event. Early fish from the fossil record are represented by a group of small, jawless, armored fish known as Ostracoderms. Jawless fish lineages are mostly extinct. An extant clade, the Lampreys may approximate ancient pre-jawed fish. The first jaws are found in Placodermi fossils.
Fish Wallpapers
Fish Wallpapers
Fish Wallpapers
Fish Wallpapers
Fish Wallpapers
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