Sharks have existed for more than 450 million years, whereas the earliest tree, lived around 350 million years ago. Not only are sharks older than trees, but they are also one of the only animals to have survived four of the five mass extinctions – now that’s impressive.
Emma Bernard, a curator of fossil fish at the Museum, says, 'Shark-like scales from the Late Ordovician have been found, but no teeth. If these were from sharks it would suggest that the earliest forms could have been toothless. Scientists are still debating if these were true sharks or shark-like animals.'
Analysis of living sharks, rays and chimaeras suggests that by around 420 million years ago, the chimaeras had already split from the rest of the group. As there are no fossils of these animals from this period of time, this is based solely on the DNA and molecular evidence of modern sharks and chimaeras. It was also around this time that the first plants invaded the land.
By the middle of the Devonian (380 million years ago), the genus Antarctilamna had appeared, looking more like eels than sharks. It is about this time that Cladoselache also evolved. This is the first group that we would recognise as sharks today, but it may well have been part of the chimaera branch, and so technically not a shark. As active predators they had torpedo-shaped bodies, forked tails and dorsal fins.
Credit : Natural History Museum
Picture Credit : Google