The brain tissue has been located in the remains of a dinosaur in Sussex, deep in the English countryside. The find appears as an unremarkable brown pebble. The fossilized material was discovered ten years ago by an amateur fossil hunter called Jamie Hiscocks; it has only recently come to light and been confirmed through scientific tests.
The fossil is thought to be 133 million years old and originates from the Early Cretaceous Period. Dinosaurs, great in size, are renowned for having tiny brains. The material recovered is likely to have come from a species of Iguanodon, a large herbivorous dinosaur. The main species, I. bernissartensis, is estimated to have weighed about 3.08 tonnes (for a typical creature).
Much of the tissue has been preserved, in mineralized form, including the surrounding brain tissue (meninges), strands of collagen, capillaries and portions of adjacent cortical tissues. The most important find is parts of the brain cortex (its outer layer of neural tissue). These structures were detected using a scanning electron microscope. The research was funded by the Natural Environment Research Council (NERC) and Christ’s College, Cambridge.
Such a fossil is very rare. This is because the chances of preserving brain tissue are incredibly small and reliant upon a special set of environmental circumstances, in this case ‘pickled’ in a highly acidic and low-oxygen body of water — as might arise from a swamp. These conditions allow the tissues to become mineralized before decay set in.
One fact is of particular interest in relation to evolution: the tissue, upon close examination, bears similarities to the brains of modern-day crocodiles and birds. These present-day creatures are descendants from dinosaurs.
The fossilized brain helps draw theories about the physiology of dinosaurs but it cannot answer questions about the intelligence of the creature, especially since much brain matter will probably have been lost to decay over time. This means the dinosaur may have had a bigger brain than is first apparent.
The findings are published in a Special Publication of the Geological Society of London. The publication is in honor of the late scientist who worked on the fossil — Professor Martin Brasier — with his associated Dr David Norman.
The research paper is titled “Remarkable preservation of brain tissues in an Early Cretaceous iguanodontian dinosaur.”
