First Known Dinosaur Brain Fossil Discovered
The 133-million-year-old specimen is a stunningly well-preserved sample of mineralized tissue from inside a Cretaceous dinosaur’s skull.
SALT LAKE CITY, UTAHAn unassuming lump found on a Sussex beach in 2004 contains the first known fossilized brain tissue from a dinosaur.
The 133-million-year-old fossil belongs to a relative of Iguanodon, an iconic herbivorous dinosaur that lived during the early Cretaceous. The fossil mostly consists of an endocast—a sediment cast of the skull cavity where the dinosaur’s brain resided.
Typically, endocasts give vital but indirect information about the brains of fossilized animals, as these sensitive organs are often the first to decay. But this endocast’s top surface contains microscopic features that appear to be directly mineralized bits of brain tissue.
Fibrous textures across the endocast surface probably started as pieces of the meninges, the tough, protective membranes that envelop and nurture the brain. Mineralized