A 鈥渂rown pebble鈥� spotted by a fossil hunter in Sussex more than a decade ago has been confirmed as the first known example of petrified dinosaur brain.
The specimen is thought to have come from a large plant eater such as iguanodon, which lived about 133 million years ago.
快猫短视频s believe the dead dinosaur鈥檚 head was buried in mud at the bottom of a swamp, allowing its brain to be 鈥減ickled鈥� and preserved.
Advertisement
In time the soft tissues became mineralised. But the fossil retained distinctive features such as the meninges 鈥� a protective membrane surrounding the brain 鈥� blood vessels, collagen and structures thought to represent the outer layer of nerve cells, or cortex.
Lucky find
A detailed study of the 鈥減ebble鈥� has revealed similarities with the brains of present-day birds and crocodiles, both close relatives of dinosaurs.
鈥淭he chances of preserving brain tissue are incredibly small, so the discovery of this specimen is astonishing,鈥� said Alex Liu, from Cambridge University鈥檚 Department of Earth Sciences, who took part in the analysis.
The find鈥檚 importance was first recognised by the late Martin Brasier, from Oxford University, who co-led the research prior to his death in a road accident in 2014.
It is highlighted in a Special Publication of the Geological Society of London published in tribute to the professor, who was one of the world鈥檚 leading palaeobiologists.
Fossil hunter Jamie Hiscocks, who discovered the specimen on a beach near Bexhill-on-Sea in 2004, and is named as one of the study鈥檚 authors, said: 鈥淚 have always believed I had something special. I noticed there was something odd about the preservation, and soft tissue preservation did go through my mind.鈥�
Pickled in bog
鈥淢artin realised its potential significance right at the beginning, but it wasn鈥檛 until years later that its true significance came to be realised,鈥� said Hiscocks.
鈥淚n his initial email to me, Martin asked if I鈥檇 ever heard of dinosaur brain cells being preserved in the fossil record. I knew exactly what he was getting at. I was amazed to hear this coming from a world-renowned expert like him.鈥�
David Norman, from Cambridge University, who worked with Brasier on the specimen, said the brain tissue had, in effect, been 鈥減ickled鈥� in a highly acidic, low oxygen environment 鈥� probably a bog, or swamp.
鈥淲hat we think happened is that this particular dinosaur died in or near a body of water, and its head ended up partially buried in the sediment at the bottom,鈥� said Norman.
鈥淪ince the water had little oxygen and was very acidic, the soft tissues of the brain were likely preserved and cast before the rest of its body was buried in the sediment.鈥�
Dinosaur with big brain?
Typically in reptiles, the brain is surrounded by a dense drainage system consisting of blood vessels and vascular chambers. The brain itself only takes up about half the space within the skull cavity.
But, surprisingly, the tissue in the fossilised dinosaur brain appears to have been pressed directly against the skull. This raises the intriguing possibility that some dinosaurs had larger brains than previously thought.
However the scientists cautioned against jumping to too many conclusions about dinosaur intelligence.
The most likely explanation was that as the brain decayed after death gravity caused it to collapse against the roof of the skull cavity, they pointed out.
鈥淎s we can鈥檛 see the lobes of the brain itself, we can鈥檛 say for sure how big this dinosaur鈥檚 brain was,鈥� Norman said. 鈥淥f course, it鈥檚 entirely possible that dinosaurs had bigger brains than we give them credit for, but we can鈥檛 tell from this specimen alone.
鈥淲hat鈥檚 truly remarkable is that conditions were just right in order to allow preservation of the brain tissue. Hopefully, this is the first of many such discoveries.鈥�
听
