Footprints embedded in the roof of the Mount Morgan caves in Queensland reveal the dinosaur that made them was crouching as it walked. Rather than stalking prey, it seems the ancient beast was just trying to stay upright in tricky conditions.
The roofs of at least nine caves around Mount Morgan have preserved dinosaur footprints made in what was once a muddy lake, including the most diverse set of tracks in eastern Australia. To palaeontologists' frustration, the caves have been shut for a decade, not only to the public but to researchers as well.
Dr Anthony Romilio of the University of Queensland made a breakthrough in understanding these tracks through a chance meeting with the daughter of Ross Staines, who documented them before the closure. Using detailed records that had sat for decades in a family cupboard Romilio recently resolved a long-standing mystery about one set of prints. Publicity about that announcement yielded a second discovery when the Mount Morgan Historical Museum informed Romilio they had photographs taken in a different part of the cave system before it was shut.
Now, Romilio has analyzed the tracks in these photographs, publishing his findings in Historical Biology.
Dinosaurs like the ones that made these prints usually walked on their toes, Romilio told IFLScience, but the prints maker's whole feet were in contact with the ground. By watching surviving dinosaurs such as emus and storks, as well as evidence from footprints elsewhere, scientists have concluded a flat-footed stance equates to holding a crouching position.
When this has been seen elsewhere it was usually from apparently stationary animals, possibly guarding their eggs. Some dinosaurs may have crouched like tigers to pounce on prey, but Romilio said in a statement, “You can rule out predatory stalking behavior, as this set of tracks was made by a two-legged plant eater called an ornithopod.”
Nor was the maker ducking beneath trees. Instead, Romilio thinks the most likely explanation is the ornithopod was keeping its center of mass low for maximum stability on a slippery mud plain. “Interestingly, this crouching dinosaur was taking bigger steps than other ‘normal’ walking dinosaurs,” he added.
The track-maker was probably the same species, and perhaps even the same individual, as the one responsible for the larger tracks from Romilio's previous discovery. Romilio told IFLScience the maker of the prints has been given the name Anomoepus, but has not been matched to a specific species known from bones or teeth. Similar, if usually slightly smaller, prints are widespread across Queensland and beyond, indicating Anomoepus was once reasonably common and survived much of the Jurassic.
Romilio hopes to one day study the caves directly, or at least send in a drone. As long as they remain closed, however, he'd love to hear from anyone with further mislaid records.