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A ‘dinosaur freeway’ is revealing its secrets in Bolivia, where researchers have found the world’s most walking tracks and even hundreds of traces from swimming dinos
A remote national park’s incredible past has been uncovered by dinosaur hunters who found a record-breaking 16,600 walking tracks and 1,378 swimming tracks.
“This is the highest number of dinosaur footprints ever found for a single tracksite thus far,” study co-author Jeremy McLarty from the Southwestern Adventist University in Texas told Live Science. “In addition to preserving the most dinosaur tracks worldwide, it also preserves the highest number of swim trackways in the world.”
While it is arid wilderness today, the site in Bolivia’s Torotoro National Park was once a shoreline where soft mud caught footprints from a high-traffic “dinosaur freeway”.
Boffins say the tracks were left by theropods: meat-eating dinos with three toes who walked on two legs. These predators, who tended to travel alone, left their marks in the deep mud between 101 million and 66 million years ago, towards the end of the Cretaceous period.
“Everywhere you look on that rock layer at the site, there are dinosaur tracks,” said McLarty. As the tracks were likely made over a relatively short time, the area was probably a popular route for theropods, possibly part of a larger freeway spanning Argentina, Bolivia and Peru.
Print shapes and the distance between footprints show that some animals were strolling and others sprinting along the shoreline. More than 1,300 tracks were left by dinos swimming in shallow water, dragging their middle toes over the seabed.
Drag marks from tails and the different lengths and widths of the footprints suggest that the dinosaurs ranged greatly in size: from a hip height of about 26 inches (65 cm) to over 49 inches (125 cm). Hundreds of tracks were also left by birds that shared the shoreline with the dinosaurs.
This study is the first scientific survey of the footprint-covered areas, of about 80,570 sqft (7,485 sqm). Some tracks were isolated, but many formed trackways, or multiple impressions left by the same animal, researchers reported in the journal PLOS One.
Boffins are thrilled by what the tracks can tell us about how dinos got around. Identifying individual prints and describing different gaits “has incredible implications for reconstructing these ancient environments and how dinosaurs and birds used them,” said palaeontologist Sally Hurst from Macquarie University in Australia.
Dr Peter Falkingham from Liverpool John Moores University told CNN that the deep mud the dinosaurs walked in can show “a lot about how these animals moved their feet”.
“It’s the deeper tracks that preserve more of the foot’s motion, which is what I’m interested in, and they have quite long trackways of such tracks,” he said. “Tracks are a record of soft tissues, of movements, and of the environments the dinosaurs were actually living in.”
The tracks, he said, “really brings these lost ecosystems to life in a way the bones don’t”.
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