New York, July 18 (IANS) Paleontologists have unearthed fossilised remains of the brain of the world's first known predators that lived about 520 million years ago.

The brain belongs to a group of animals known as anomalocaridids or better known as abnormal shrimps.

Long extinct, these fierce-looking arthropods were first discovered as fossils in the late 19th century but not properly identified until the early 1980s.

The fossilised brain is surprisingly simple and less complex than those known from fossils of some of the animal's prey.

"It turns out the top predator of ancient time had a brain that was much less complex than that of some of its possible prey and that looked surprisingly similar to a modern group of rather modest worm-like animals," said Nicholas Strausfeld, director of University of Arizona's centre for insect science.

The brain in the fossil, a new species given the name Lyrarapax unguispinus, suggests its relationship to a branch of animals whose living descendants are known as onychophorans or velvet worms.

These wormlike animals are equipped with stubby unjointed legs that end in a pair of tiny claws.

The fact that the brain of the earliest known predator appears much simpler in shape than the previously unearthed brains of its contemporaries begs intriguing questions.

According to Strausfeld, it is possible that predators drove the evolution of more complex brains.

The paper appeared online in the journal Nature.