Pea-Brain? Scientists Unearth First Known Dinosaur Brain Fossil From 133 Million Years Ago

From a simple discovery of a pebble-like fossil by Jamie Hiscocks during his journey on a rocky beach in Sussex, England, paleontologists now claim the possibility of it being the first-ever mineralized brain of a dinosaur. How did it happen on a fast-decaying organ?

According to the National Geographic, the study and its findings were written for a special publication of the Geological Society of London to commemorate the works and efforts done by the late Martin Brasier, a renowned paleontologist. On the paper, which was a collaborative effort from different international experts, they discussed the possibilities of getting new information from the fossil.

Identified as an endocast or a portion of the skull cavity which is a sediment cast in which a dinosaur's brain can be found, the fossil was linked to be a possible relative of Iguanodons that thrived some 133 million years ago. These dinosaurs were described to have four legs but can walk with either four or two. They are large and herbivorous, with a notable spike on their thumbs which was previously thought to be their horns.

There have been several debates on how to prove that the endocast found has preserved the soft tissues of the dinosaur's brain. Since the brain itself easily decays, the team hypothesized that probably, the dinosaur died on a stagnant body of water. With its stomach floating above the water, the head could have been partially burrowed on the ground. While the body decays on the water, the dinosaur's skull served as a bowl that housed the brain which was said to be "pickled" through the water's high acidity and low-oxygen content.

To analyze the fossil, the team used the scanning tunneling microscopy approach. “What we found were very fine detailed bundles of what seemed to be collagenous fibers, which you’d expect in the outer protective tissues of the brain,” said Alex Liu, a co-author of the paper and Brasier's former doctorate student. “And these are interspersed with open tubes that branch and run around the edges of the specimen, and these seem to be the capillaries, which again you’d expect in that position on the surface.”

Though the paper might get a lot of scrutiny, John Hopkins University's Amy Balanoff said it can also provide good insights to further understand dinosaur brain evolution. It was also noted that the paper adds more evidence that there is a chance that neural tissues can be fossilized, and soon, they might even discover more.