Ancient Fossil Brain Gives Clues on How Arthropods of Today Got Heads

Odaraia alata. Image: Jean Bernard Caron (Royal Ontario Museum)
Odaraia alata. Image: Jean Bernard Caron (Royal Ontario Museum)
When Javier Ortega-Hernández realised he was looking at a well-preserved fossilised brain over 500 million year old at the Smithsonian Institute, he knew he’d made a remarkable discovery.


„Preserved nervous systems allow us to understand the origin of the head in arthropods, the animal group that includes insects, crustaceans, millipedes and spiders,“ said Ortega-Hernández, who is a research fellow in Paleobiology in the Department of Earth Sciences at the University of Cambridge, over email. As arthropods are all over the world these days, Ortega-Hernández noted that figuring out how they originated would lead to greater understanding on the origin of modern ecosystems and complex animal life.

In a study published today, Ortega-Hernández reports on some of the oldest brains preserved in the fossil record, which originated from a middle Cambrian locality known as the Burgess Shale in British Columbia, Canada. The Cambrian period, more commonly known as the Cambrian Explosion, is an era dating back 500 million years when major groups of animals first appear in the fossil record—primarily when arthropods with hard exoskeletons and jointed limbs emerged. Prior to this period, organisms on earth were mostly made up of algae and soft-bodied jellyfish-like creatures.

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