Nathan Hrushkin saw the fossils sticking out of a rock while walking through Horseshoe Canyon in Canada's Alberta province with his dad.
A 12-year-old wannabe palaeontologist showed the professionals how to do it when he discovered a dinosaur skeleton dating back 69 million years while out hiking.
They'd visited this particular site before in Horseshoe Canyon, but only found bone fragments, Nathan said.
Excavations of the skeleton were completed on Thursday.
"I wasn't even excited, even though I know I should have [been] ..."
Nathan, who has been interested in dinosaurs since he was six, often goes hiking in the Nature Conservancy of Canada's protected site in the Albertan Badlands with his father. "I was in so much shock that I had actually found a dinosaur discovery", he added.
Nathan and his dad travel to Drumheller from their home in Calgary every summer to hunt for dinosaur bones. The fossilised bones were poking out of the side of a hill.
"He called down to me, he's like, 'Dad, you need to get up here, ' and as soon as he said that I could tell by the tone in his voice that he found something", Dion Hrushkin said.
Nathan Hrushkin and his father have hiked through the Drumheller, Alta., area for years.
"The bones were removed in protective jackets made of burlap and plaster and taken back to the museum lab for cleaning and research", Nature Conservancy Canada said.
"It looked like the end of the thigh bone and was sticking out from the ground".
They logged the find with the Royal Tyrrell Museum, in the nearby town of Drumheller, which then asked for photos and Global Positioning System coordinates, before sending a team to inspect further.
The fossil was a humerus bone from the arm of a juvenile hadrosaur - a duck-billed dinosaur that lived about 69 million years ago, according to a news release from the Nature Conservancy of Canada.
Nathan said the experience has motivated him even more to pursue his dream.
Being aware that the fossils are protected by law, the report said that when they arrived home, Nathan and his father logged onto the website for the Royal Tyrrell Museum, which is located in Alberta. The museum asked them to send photos and Global Positioning System coordinates of their discovery.
Since Nathan's discovery, between 30 and 50 bones have been found by paleontologists in the canyon's wall, all of which belonged to a single young hadrosaur aged between three and four years old. Leila believed deeply in the importance of maintaing the canyon's natural state and worked for many years as an interpreter, where she introduced visitors to its many unique features.
"But after my discovery, it's most definitely the Hadrosaur".
The fossil comes from a period of time "we know very little about", Therrien said, which means Nathan's find "will help us fill this big gap in our knowledge of dinosaur evolution".
François Therrien, curator of Dinosaur Palaeoecology at the Royal Tyrrell Museum of Palaeontology, working to unearth the dinosaur bones at the Nordwell property.
Nathan says he's enjoyed learning more about dating dinosaur bones, and that the whole process has been "surreal".
"It's going to be great to see them, after months of work", he said, "finally take something out of the ground", the report quoted.