Bizarre three-eyed predator hunted the ocean half a billion years ago

A predator that swam Earth's oceans more than half a billion years ago is unlike any creature that lives on our planet today

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Mosura fentoni possessed three eyes, grasped its prey with spiny claws, ate with a circular, tooth-lined maw, swam with the aid of flippers that lined either side of its body, and had 26 body segments more than any other radiodont, the extinct group of animals to which it belonged.

Luckily, it would only have been about as long as your finger most things back then were pretty small. But its segmented tail end has fascinated paleontologists Joe Moysiuk of the Manitoba Museum and Jean-Bernard Caron of the Royal Ontario Museum, who characterized the strange beastie from its fossilized remains in the famous Burgess Shale.

They named Mosura for its resemblance to a moth, even though the relationship is distant and tenuous.

"Mosura has 16 tightly packed segments lined with gills at the rear end of its body," Moysiuk explains. "This is a neat example of evolutionary convergence with modern groups, like horseshoe crabs, woodlice, and insects, which share a batch of segments bearing respiratory organs at the rear of the body."

The oceans of Earth's Cambrian period, between around 539 and 487 million years ago, were a different place than our planet today. That was when life really took off, and the ocean started to thrive.