A caiman skeleton has been discovered under a primary school floor.
The skeleton was found when the floor of one of the classrooms at Ysgol Bodringallt, in Pentre, Rhondda Cynon Taff, was lifted during renovation work on Wednesday.
Head teacher Dr Neil Pike said workers were "shocked" and "didn't expect to find such a thing".
He said people had talked for decades of a crocodile being buried at the site.
"I'd heard a story that parents and school staff had buried a crocodile under the school some time between the two world wars," he said.
"I thought it was an old myth and I didn't take much notice until Thursday morning when I went to check the building work at the school. Laid on the floor of the hall was the crocodile.
"It is said to have been exhibited for some time before burial. Perhaps we will know all the history now."
Former head of school Marian Roberts said she understood the skeleton was a caiman - a creature belonging to the same family as the crocodile and alligator, but with a shorter, broader head and longer and narrower teeth than some crocodiles.
She said the timing of the discovery was "amazing", as the school was currently celebrating the 40th anniversary of its transition to a Welsh-language school.
Mrs Roberts, who was once a pupil at the school, said: "My dad had been talking about this crocodile since I was a little girl.
"When I went there in 1961, he asked me where the crocodile was.
"When I was the head teacher then, people who were coming to the school asked if he was still there - he obviously had an impact on people."
Asked what would happen to the skeleton now, Dr Pike said he was not sure.
"Bury it again or display it? We'll see," he said.