Known as dermal denticles, they decrease drag and turbulence – allowing the shark to swim faster and more quietly.

Sharks and rays are one of the most successful vertebrate groups still alive today.

Due to their lifelong replacement, the teeth are among the most common fossil finds.

Their skeletons are made of cartilage which, unlike bone, rarely survives fossilisation – making the discovery in Dorset particularly rare.

Durnonovariaodus, described in PeerJ, differs from all other known hybodontiforms – including those with similarly shaped teeth.