The first great predatory reptile

What replaced the fearsome Dunkleosteus terrelli as top predator of the seas? The sharks survived the Permian extinction, but the large marine reptiles arose much more quickly than we previously thought. This 8-meter monster appeared at least 244 million years ago. It was shaped something like an oversized four-flippered dolphin, but the head is unmistakeably that of an apex predator.  Thalattoarchon saurophagis ("lizard-eating ruler of the sea") was the first of the icthyosaurs, which would go on to produce giants three times this length - or more.