Much like tropical fish today, these flying sharks probably traveled in schools. This is a good survival tactic for fish that might have grown only a foot and a half long. They were heavily armored creatures with huge eyes. These sharks had denticles, tooth like structures on the leading edge of their pectoral fins. When danger threatened, they escaped the jaws of larger predators on their wing like fins.

Three hundred million years ago, sharks were evolutionary innovators. They filled many more ecological niches than they do today. Each animal was stranger looking than the next. Back then, sharks were amazingly diverse, filling up about 60% of all fishes, compared with only 3% today. Shark researchers today attempt to find fossilized sharks, which is a matter of luck, even for those well experienced. They search for the missing links in shark evolution and the relatives of modern sharks, skates and rays.

The first sharks appeared in the oceans around 400 million years ago, but they bore little resemblance to the ones that inhabit the seas today. Edestus giganteus grew to a size as large as today’s great white and had a set of gigantic scissor like jaws. The helicoprion had teeth that were designed in a whirl and designed for crushing hard shells. A close relative of toddy’s great white, but twice its size, the megalodon was perhaps the largest of all predatory fish. It became extinct between 1 and 3 million years ago but is still regarded as a modern shark. Modern sharks began there rise to dominance late in the age of the dinosaurs , some 140 million years ago, at the same time another group branched off, evolving into the rays and skates of today. Some rays still look a bit like sharks, others don’t at all.

Sharks were obviously an evolutionary hit. Today any shark with more than five pairs of gills are thought to be a more ancient species.