Oldest Fossilized Brain Found

The oldest fossilized brain has been found in a 300 million year old fish. The iniopterygians (pictured above) are an extinct relative of today's ratfish, distantly related to sharks and rays. "Fossilized brains are unusual, and this is by far the oldest know example," says John Maisey, the curator of paleontology at the American Museum of Natural History in NY. This particular fish has a large brain case compared to its pea sized brain. The largest lobe of the brain was devoted to vision which is consistent with the iniopterygians' large eye sockets in the skull. This suggests that it depended largely on its eyes for locating and catching prey.

The fish, which was discovered in Kansas and sent to France for CAT scans, inhabited an ocean that spanned the Midwestern United States 300 million years ago. "The brain … is remarkably soft tissue—brain tissue is mostly water," Maisey said. "To preserve anything is quite remarkable." This discovery is very important because now researchers have a glimpse into the beginnings of the vertebrate brain, a very rare opportunity. "The evolution of the brain lies at the core of vertebrate history," Maisey said. By studying this early gray matter we can hope to learn more about the evolution of our own brains.

-Jillian O'Keefe (4)