Biologists are now studying a 500 million year old brain that could hopefully provide clues about the evolution of animal heads during ancient times. This fossil is considered as rare evidence about the pivotal changes in the brain that suggests how heads are shaped by biological factors and environemntal ones, half a billion years back.

Like Us on Facebook

Researchers are now examining arthropods which is a group of animals where modern day spiders belong to including insects and crustaceans. Scientists have chosen a soft shelled group of arthropods called trilobites and another ancient creature that looks like a torpedo that has a hard shell and limbs.

Upon closer inspection of the ancient creatures, there's a hard plate on the head called the anterior sclerite and simple photoreceptors which look like eye like structures on the head, that are linked to the brain, that are also similar to modern day arthropods.The fossil record also suggest that some of these animals possess this feature while some did not, also depending where it is located on the head.

A common predator originating from the same period called anomalocaridids, were also discovered to have the same head plate that suggests a common ancestor among the animals. These were considered to be ancestors of arthropods even if their body structures are quite different.

Researchers now believe that this anterior sclerite could be the "missing link" between these two groups.  

According to Javier Ortega-Hernández of the University of Cambridge, this anterior sclerite disappeared in modern arthropods as it has been most likely merged with other head parts during the evolution of this group.

These fossils are now presenting that there are transitional stages between soft bodied worm creatures and arthropods who now have exoskeletons and jointed limbs, which shows a period of crucial transformation. 

In the Cambrian Explosion, biodiversity among animals were produced at a dynamic rate that generated many kinds of animals today. The first body adaptations were hard shells and jointed limbs as previous life forms mostly consisted of algae and jellyfish.

This step is pivotal in the evolutionary process of animals, mainly transitioning from soft shells to hard shells which have been identified during this new study upon investigating these ancient fossils. 

These fossils were recovered from the Burgess Shale in the western region of Canada which is also the most fossil rich areas on the planet.

The fossils found here are so intact that soft tissues including brains were preserved well for scientists to study. Soft tissues are usually attacked by bacteria and chemical and geological processes before becoming fossilized. Researchers now consider this specimen as the most complete fossilized brain ever found.

This study is published in the journal Current Biology. 

Tags500 million year old brain, cambrian era, arthropods, ancient spiders, ancient animals, 500 million years old brain fossil heads, brain fossil, trilobites, cambrian explosion