The team believes the piece of brain was essentially pickled in a highly acidic and low oxygen body of water shortly after the dinosaur's death. The enormous animal might have keeled over near a bog or swamp. Its cause of death is unknown, but Liu said that "the soft tissues of the brain were likely preserved and cast before the rest of its body was buried in the sediment."
While it's fortunate that where the dinosaur fell allowed part of its brain to be pickled for posterity, Norman points out that the "acidic 'pickling' process would have denatured any of the biological molecules." That means no DNA can now be extracted from the fossil.
Nevertheless, "Any time we get soft tissue preservation in a dinosaur it's cause for celebration since it gives us such a unique window into the biology of these animals," Lawrence Witmer, a professor of anatomy and paleontology at Ohio University who did not work on the research, told Seeker.
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Vertebrate paleontologist Darren Naish of the University of Southampton was not too shocked when he first learned of the fossil's discovery.
Naish said: "The idea that a dinosaur's brain might be preserved as a fossil perhaps seems improbable, but a large number of recent discoveries have shown that soft structures of virtually any kind can be preserved in the fossil record when the conditions are right"
While the Iguanodon-like dinosaur's full brain was probably not as large as first theorized, Naish pointed out that "size isn't everything when it comes to brain organization and function." Honeybees, for example, have very small brains, but are extremely intelligent.
It is, however, possible that this particular dinosaur wasn't the sharpest tool in the shed. Norman said that the dinosaurs on the evolutionary line leading to birds likely had larger brains. They managed to survive the mass extinction event around 65 million years ago.