text: Image of specimen. Credit: Jamie Hiscocks An unassuming brown pebble, found more than a decade ago by a fossil hunter in Sussex, has been confirmed as the first example of fossilised brain tissue from a dinosaur. 
   
   The fossil, most likely from a species closely related to Iguanodon, displays distinct similarities to the brains of modern-day crocodiles and birds. Meninges - the tough tissues surrounding the actual brain - as well as tiny capillaries and portions of adjacent cortical tissues have been preserved as mineralised 'ghosts'. 
   
   The results are reported in a Special Publication of the Geological Society of London, published in tribute to Professor Martin Brasier of the University of Oxford, who died in 2014. Brasier and Dr David Norman from the University of Cambridge co-ordinated the research into this particular fossil during the years prior to Brasier's untimely death in a road traffic accident. 
   
   The fossilised brain, found by fossil hunter Jamie Hiscocks near Bexhill in Sussex in 2004, is most likely from a species similar to Iguanodon: a large herbivorous dinosaur that lived during the Early Cretaceous Period, about 133 million years ago. 
   
   Finding fossilised soft tissue, especially brain tissue, is very rare, which makes understanding the evolutionary history of such tissue difficult. "The chances of preserving brain tissue are incredibly small, so the discovery of this specimen is astonishing," said co-author Dr Alex Liu of Cambridge's Department of Earth Sciences, who was one of Brasier's PhD students in Oxford at the time that studies of the fossil began. 
   
   The video will load shortly Animation of specimen. Credit: University of Manchester 
   
   According to the researchers, the reason this particular piece of brain tissue has been so well-preserved is that the dinosaur's brain was essentially 'pickled' in a highly acidic and low-oxygen body of water - similar to a bog or swamp - shortly after its death. This allowed the soft tissues to become mineralised before they decayed away completely, so that they could be preserved. 
   
   "What 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," said Norman. "Since 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." 
   
   Working with colleagues from the University of Western Australia, the researchers used scanning electron microscope (SEM) techniques in order to identify the tough membranes, or meninges, that surrounded the brain itself, as well as strands of collagen and blood vessels. Structures that could represent tissues from the brain cortex (its outer layer of neural tissue), interwoven with delicate capillaries, also appear to be present. The structure of the fossilised brain, and in particular that of the meninges, shows similarities with the brains of modern-day descendants of dinosaurs, namely birds and crocodiles. 
   
   In typical reptiles, the brain has the shape of a sausage, surrounded by a dense region of blood vessels and thin-walled vascular chambers (sinuses) that serve as a blood drainage system. The brain itself only takes up about half of the space within the cranial cavity. 
   
   Environmental scanning electron microscopy images of tubular structures on the exterior of the Bexhill iguanodontian cranial endocast and within the outer laminar layer, interpreted here as meningeal blood vessels. Credit: David Norman 
   
   In contrast, the tissue in the fossilised brain appears to have been pressed directly against the skull, raising the possibility that some dinosaurs had large brains which filled much more of the cranial cavity. However, the researchers caution against drawing any conclusions about the intelligence of dinosaurs from this particular fossil, and say that it is most likely that during death and burial the head of this dinosaur became overturned, so that as the brain decayed, gravity caused it to collapse and become pressed against the bony roof of the cavity. 
   
   "As we can't see the lobes of the brain itself, we can't say for sure how big this dinosaur's brain was," said Norman. "Of course, it's entirely possible that dinosaurs had bigger brains than we give them credit for, but we can't tell from this specimen alone. What's 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." 
   
   "I 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. Martin realised its potential significance right at the beginning, but it wasn't until years later that its true significance came to be realised," said paper co-author Jamie Hiscocks, the man who discovered the specimen. "In his initial email to me, Martin asked if I'd 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." 
   
   Explore further: A new brain-warp technique that helps to reconstruct fossil brains 
   
   More information: Geological Society, London, Special Publications (2016). DOI: 10.1144/SP448.3 
   
   ||||| Researchers Say They've Found A Bit Of Fossilized Dinosaur Brain 
   
   Enlarge this image toggle caption Jamie Hiscocks/University of Cambridge Jamie Hiscocks/University of Cambridge 
   
   A rusty-brown rock found on a beach by a fossil hunter might contain a bit of preserved dinosaur brain. 
   
   If so, it would be the first time scientists have ever found fossilized brain tissue from a dinosaur. 
   
   The fossil comes from a species closely related to Iguanodon, a large herbivore that lived about 130 million years ago. A collector named Jamie Hiscocks found it in 2004, near Bexhill in the United Kingdom. 
   
   "He picked it up and noticed that it was slightly unusual in its shape and its texture," says Alex Liu of the University of Cambridge. "There's a series of bumps to this specimen that are quite characteristic of it fitting into the brain case of a dinosaur." 
   
   This kind of fossil gets made when sediment fills up a dinosaur's skull cavity and hardens. Later, if the skull breaks off and disappears, what's left behind is a solid object that reveals the shape of the skull's inner cavity. 
   
   What's different about this particular example, Liu says, is that the outer millimeter or so of this fossil "is actually mineralization of some of the soft tissue structures that were preserved before they decayed away within the original dinosaur brain case." 
   
   The dead dinosaur's head may have fallen into a bog or a swamp, he says, where chemical conditions allowed the soft tissues to become mineralized. 
   
   Hiscocks showed his unusual fossil to Martin Brasier of the University of Oxford, who was the first to recognize that it might contain preserved brain tissue. A team of researchers examined the sample in detail and found what they believe are tough collagen fibers and tiny blood vessels that are part of the protective outer covering of the brain. 
   
   Lower down, they see hints of another textured surface that might be the actual top of the brain itself. "It's a little bit harder to convince yourself that it's definitely there," Liu says, "just because it is deeper within the specimen so it's harder to see it on the surface. But we think that we have actually got some of that tissue preserved, as well." 
   
   One member of the research team is describing the find Thursday at the annual meeting of the Society of Vertebrate Paleontology in Salt Lake City. A full report appears in a special publication of the Geological Society of London that's a tribute to Brasier, who died in 2014 before he was able to publish on this find. 
   
   Any claim of preserved soft tissue from a dinosaur tends to be controversial, and the idea that scientists might have part of an actual brain is going to get a lot of scrutiny. 
   
   "That's a remarkable claim, just because brain tissue turns out to be one of the first things that decomposes after an animal dies," says Lawrence Witmer of Ohio University, a paleontologist who studies the soft tissues of dinosaur heads. 
   
   He thinks the scientists make a "compelling case" that they have part of the protective outer covering of the brain. 
   
   "What's potentially even more exciting is that they are very cautious, as good scientists are, about the possibility that they might even have some preservation of the neural tissue of the brain underneath," notes Witmer, who says this is a surprise. "We would never expect to see actual brain tissue preserved." 
   
   Witmer thinks the bar for evidence should be very high. "These are, in a sense, extraordinary claims," he says. 
   
   Amy Balanoff of the Center for Functional Anatomy and Evolution at Johns Hopkins University calls the find "intriguing." But she'd like to see comparisons to the anatomy of birds or crocodiles, and she wants to see more details on the branching pattern of the putative blood vessels. 
   
   "I'm not convinced," says Mark Norell of the American Museum of Natural History. He's concerned that the paper describing the find was published even though the fossil specimen is not yet in a public repository, such as a museum, where others can study it. What's more, he thinks the report generally doesn't reflect the state-of-the-art knowledge on dinosaur brain anatomy. 
   
   If the finding stands up to scrutiny, it's unclear what the discovery could reveal about dinosaurs' intellectual capacity. 
   
   In modern reptiles, Liu says, the brain does not take up the whole brain cavity. The brain is surrounded by a lot of protective, spongy tissue. But in this fossil, the brain's protective covering seems to be thin, suggesting that the brain was filling more of the cavity and the dinosaur could have had a greater mental capacity. 
   
   "Understanding of dinosaurs as a whole has changed completely in the last 20 or 30 years. Dinosaurs are now seen to be much more mobile, agile, smart creatures," Liu says, "and this is just one line of evidence that supports that view." 
   
   One thing that's almost certain is that scientists will now be going back and looking with new eyes at old fossils that are already in collections, according to Witmer. 
   
   "It's not like we didn't think dinosaurs had brains," Witmer says, but "if you don't know what you're looking for, you're not likely to find it."
target: – Are we one step closer to Jurassic Park? Probably not, but researchers do believe they've found the first ever example of fossilized brain tissue from a dinosaur, National Geographic reports. The fossil was found on an English beach in 2004, but its unique trait—mineralized pieces of brain tissue—was announced in a study Thursday. "The chances of preserving brain tissue are incredibly small, so the discovery of this specimen is astonishing," Phys.org quotes study coauthor Alex Liu as saying. Researchers believe the dinosaur, a relative of the Iguanodon, sank upside down into a pond after it died. The pond water "essentially pickled" the dinosaur's brain, and the pickled tissue was eventually replaced by minerals. The outer millimeter of the fossil seems to include mineralized blood vessels and bits of the membrane that covered the brain, NPR reports. Researchers believe it may also contain mineralized pieces of the brain itself. “That is the nearest I suspect we’re ever going to get to the whole [brain],” paleontologist David Norman tells NatGeo. One result of the new discovery: Researchers say it may show dinosaurs were smarter than we've been giving them credit for. In modern reptiles, the brain doesn't take up the entire brain case in the skull. That appears not to have been the case in this dinosaur, meaning it may have had a larger brain than previously believed. Norman says it appears the dino was at least as smart as a modern crocodile. (A bus-sized dinosaur comes with a surprise.)