A schoolboy has discovered what appears to be an extremely rare fossil of footprints from more than 300 million years ago in Cornwall.
Bruno Debattista, aged 10, found a piece of shale rock containing what he thought might be a fossilised imprint while on holiday in the Duchy.
He had no idea at the time that the imprint revealed the movements of Cornish marine life hundreds of millions of years ago.
Later Bruno, from Oxford, took it to an after-school club at Oxford University's Museum of Natural History.
University experts were astonished to find that it appeared to contain trackways left by horseshoe crabs crawling up a muddy shore in the Duchy around 320 million years ago.
Chris Jarvis, education officer at the museum and organiser of the after-school club, said: "Footprints of this age are incredibly rare and extremely hard to spot, so we were amazed when Bruno produced them.
"Still more impressive is the fact that Bruno had a hunch they might be some kind of footprints, even though the specimen had some of our world expert geologists arguing about it over their microscopes."
The museum believes Bruno's fossil shows footprints of a pair of mating horseshoe crabs laid down during the Carboniferous period, some 308-327 million years ago.
Bruno, who attends Windmill Primary School in Oxford, and his family have decided to donate the fossil specimen to the museum's collection.
The natural history after-school club is run by the museum's education department and encourages year six children to develop their interest in the natural world, in the hope that some might become the next generation of geologists and zoologists.
"Unfortunately, the excitement and motivation that many children instinctively feel for studying nature is often lost during their teenage years as it is seen as 'uncool' or a bit 'weird', and science can become text-book oriented and exam-driven during secondary school," Mr Jarvis said.