A New Fossil Sporting An Incredible Fossilised Brain

The first animals evolved some 700 million years ago. To create a large surface area for absorbing nutrients from the water, they used a fractal system of tubes which branched off from a central stem. They could replicate their bodies and heal damage at an incredible rate, but had almost no complexity and little organisation.

A fossil of one of the earliest animals on
the planet, devoid of complex structures

This all changed 600 million years ago when these ancient, primitive organisms evolved bilateral symmetry. This allowed for the creation of complex tissues and organs. This was a massive leap forward in diversity and evolutionary success, resulting in the skull, and more importantly, the brain which it protected.

The brain allowed for greater control over the body and the processing of information gathered by the limbs. This is why creatures such as squid are quite intelligent as they need high power brains to interpret all the information provided by their individual tentacles. As a result, it is possible to tell how advanced a creature is from the state of its brain. While some species of worms could easily outsmart certain species of fish in logic puzzles.

The exquisitely preserved 520 million
year old fossil of Fuxianhuia protensa 

A fossil unearthed in 520 million year old mud-stones laid down on the bed of a shallow sea in the region, which would become the world famous Chengjiang formation in the Yunnan province in Southern China, preserves the oldest known brain in the Earth's fossil record.

Discovered by researchers from the University of Arizona, the 7 and a half centimetre long branchiopod, named Fuxianhuia protensa, shows clear and well defined structures similar to antennae and eye stalks connected to a brain inside the skull. What makes it interesting is that the brain is tripartite. Such divisions are also found in the brains of many different groups of crustacean, insect and centipedes today.

The antennae and eyes of Fuxianhuia connected to its brain

The similarities between the brains in both Fuxianhuia and its descendants show that the basic layout and structure of the organ has changed little in over 520 million years. 'No one expected such an advanced brain would have evolved so early in the history of multicellular animals,' said Nicholas Strausfeld from the University of Arizona's department of neuroscience.

The Cambrian Explosion, which Fuxianhuia was a part of, was the most important event in the evolution of life. It is fundamental to understanding the diversity of life. Every animal and plant can trace its roots back to this single event in the history.