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Spineless Dorsal Fins Basking Goblin Crocodile Megamouth Thresher Sharks
3,474 wordsDifferent Types of Sharks INTRODUCTION Although sharks belong to the class Chondrichtyes, there are many different types. Sharks arose about 350 million years ago and have remained virtually unchanged for the past 70 million years and still comprise a dominant group. It is thought that sharks almost certainly evolved from placoderms, a group of primitive jawed fishes. It took a long series of successful and unsuccessful mutations with fin, jaw positions etc to give us all the different designs o...
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