Australia's oldest dinosaur fossil has been identified more than 60 years after a teenager found it while fossicking in a sandstone quarry.
The 18.5cm footprint was found at Albion in Brisbane's inner south by Bruce Runnegar in 1958 while he was looking for plant fossils.
University of Queensland palaeontologist Anthony Romilio has confirmed the footprint is that of a prosauropod, a small dinosaur from the early Late Triassic period 230 million years ago.
It was the oldest known dinosaur fossil in Australia and one of the oldest in the world, Dr Romilio told AAP.
It proved that dinosaurs were present in Australia a lot earlier than previously recognised.
"It shows how globally significant discoveries can remain hidden in plain sight,” Dr Romilio said.
The sandstone found at Petrie's Quarry was used for buildings like Brisbane's General Post Office and people would visit to look for plant fossils from the Triassic.
"It happened that when Bruce was in high school in 1958 he and his buddies came across this particular fossil, chiselled it out and he's been hanging onto it for over six decades," Dr Romilio said.
The teenage fossil fossicker went on to become a palaeontologist and decades later got in touch with Dr Romilio when he learned of his use of new photographic and 3D technology to study dinosaur footprints.
“When I saw Dr Romilio’s ability to reconstruct, analyse and map dinosaur footprints, I decided to reach out to have the fossil formally documented," Professor Runnegar said.
“More than 60 years after we found it, it’s extraordinary to see it recognised as Australia’s oldest dinosaur fossil."
Comparisons with other fossilised footprints and skeletal remains from other finds around the world enabled the identification of the dinosaur as a prosauropod.
“It’s likely the dinosaur was walking through or alongside a waterway when it left the footprint, before it was then preserved in sandstone," Dr Romilio said.
The previous oldest-known dinosaur fossils in Australia were footprints found in Ipswich, west of Brisbane, dating from around 215 million years ago.
The prosauropod was a primitive relative of later long‑necked dinosaurs and was roughly 75cm to 80cm tall at the hip and weighed about 140kg, Dr Romilio said.
The fossil is now at the Queensland Museum where it will be available for ongoing research.
