Experts revisited the footprints of a 220-million-year old coal miner in Ipswich in Australia. They concluded that they belonged to a timid, long-necked herbivore and not a larger, raptor-like animal.
This updated assessment was possible thanks to a more thorough analysis of the original footprints, including their orientation and spacing, as well as comparisons to footprints from other dinosaurs.
Researchers concluded that the creature was not a Triassic predator but a more timid and aggressive plant eater. It is not yet clear which species the footprints belong.
Casting of the footprint plaster. (Anthony Romilio et al, Historical Biology, 2021)
Anthony Romilio, a paleontologist at the University of Queensland, Australia, says that "for years it has been believed that these tracks are made by a huge predator that was part of Eubrontes' dinosaur family, with legs more than two meters [6.6 feet] high."
"This idea caused a sensation decades back because no other meat-eating dinosaur on the planet approached that size during Triassic."
"But, our research has shown that the tracks were made by a smaller dinosaur from the Evazoum vegetarian dinosaurs. It had legs approximately 1.4m [4.6ft] high and a body length about 6m [19.7ft].
The large footprints of large birds would be approximately 200m (656 feet below the ground). They were made on moist layers of plant debris and then filled with silt to preserve them for human discovery many millennia later.
The plant material was eventually converted to coal, which was mined in the 1960s. This revealed the natural casts from dinosaur footprints. Although the mine has been closed for many years, plaster casts of the finds were made.
These casts were then converted to 3D models. Researchers could assess small details like how a foot might be dragged to increase the footprint size, position of the claws and overall gait, and rethink the implications.
Romilio says that "Unfortunately, previous researchers couldn't directly access the footprint specimen for study. Instead, they relied on old drawings and photos that were lacking detail."
This new study also used decades of research that was not available in 1964. It analyzed the footprints of Eubrontes dinosaurs and Evazoum dinosaurs all over the globe in great detail.
These comparisons, along with a closer look at the plaster casts made originally, have helped experts to be more certain that we are looking at a friendlier dinosaur that ate plants. However, more specimens would be needed to determine which species it is.
It is difficult to assess dinosaur characteristics solely from footprints. The researchers behind this new study want to not diminish the hard work of paleontologists who came before.
Hendrik Klein, a German paleontologist from the Saurierwelt Palaontologisches Museum, said that "this is still a significant discover even if it's not a scary Triassic carbivore."
"This is the earliest evidence that we have for this kind of dinosaur in Australia. It marks a gap of 50 million years before the first known quadrupedal Sauropod fossils."
Historical Biology published the research.
