Around 50 years ago, fossil footprints of what was assumed to be a “raptor-like” predatory dinosaur were found in an Australian coal mine. However, new research from the University of Queensland has discovered that the fossil was in fact of a long-necked herbivore.
Upon re-analyzing the footprints, paleontologist Dr. Anthony Romilio was able to conclude that they belonged to the vegetarian Prosauropod and could be dated back to around 220 million years ago, around the end of the Triassic Period.
“For years it’s been believed that these tracks were made by a massive theropod predator that was part of the dinosaur family Eubrontes, with legs over two meters tall,” explained Dr. Romilio. “This idea caused a sensation decades ago because no other meat-eating dinosaur in the world approached that size during the Triassic period.”
However, it was expected at the time that there was something incorrect about this conclusion. “Unfortunately, most earlier researchers could not directly access the footprint specimen for their study, instead relying on old drawings and photographs that lacked detail,” explained Dr. Romilio.
The new conclusion made a lot more sense as the legs of the Prosauropod were in fact smaller, with legs around 1.4 meters in length and a body length of six meters.
The prosauropod dinosaur footprints are known scientifically as ‘Evazoum’ and were made on the water-sodden layers of ancient plant debris.
“After millions of years, the plant material turned into coal which was extracted by the miners to reveal a ceiling of siltstone and sandstone, complete with the natural casts of dinosaur footprints,” explained study co-author Hendrik Klein. “This explains why today they occur in an upside-down position right above our heads,”
Whilst the mine closed many years ago, the fossil was mapped and preserved through plaster casts by geologists at the Queensland Museum in 1964. “We made a virtual 3D model of the dinosaur footprint that was emailed to team members across the world to study,” said Klein.
“The more we looked at the footprint and toe impression shapes and proportions, the less they resembled tracks made by predatory dinosaurs – this monster dinosaur was definitely a much friendlier plant-eater.”
The findings are published in the journal Historical Biology, and the Prosauropod footprint can be seen at the Queensland Museum in Brisbane.