Authorities on Tuesday announced the discovery of hundreds of meters of well-preserved dinosaur tracks with visible toes and claws in the Italian Alps, in a region preparing to host the 2026 Winter Olympics.
"This set of dinosaur footprints is one of the largest collections in all of Europe, in the whole world," Attilio Fontana, head of the Lombardy region in northern Italy, told a press conference.
The tracks, which are over 200 million years old, were discovered in the Stelvio National Park, in an area between the towns of Bormio and Livigno, which host part of the games.
Nature photographer Elio Della Ferrera first spotted the imprints in September on an almost vertical rocky slope.
Some measured up to 40 centimeters (16 inches) in diameter.
The collection "extends for hundreds of metres and also represents a series of animal behaviors, because in addition to seeing animals walking together, there are also places where these animals meet," Fontana said.
Della Ferrera called in paleontologist Cristiano Dal Sasso from Milan's Natural History Museum, who assembled a team of Italian experts to study the site.
"It's an immense scientific heritage," Dal Sasso said in the region's press release.
"The parallel walks are clear evidence of herds moving in synchrony, and there are also traces of more complex behaviors, such as groups of animals gathered in a circle, perhaps for defense."
The tracks, currently covered by snow and off the beaten track, are preserved in Upper Triassic dolomitic rocks, dating back approximately 210 million years.
Most of the footprints are elongated and made by bipeds. The best-preserved ones bear traces of at least four toes.
That suggests they belong to prosauropods, herbivorous dinosaurs with long necks and small heads, which are considered the ancestors of the large sauropods of the Jurassic period like the Brontosaurus, the experts said.
Prosauropods had sharp claws, and adults could reach up to 10 meters in length.
There may also be tracks of predatory dinosaurs and archosaurs, the ancestors of crocodiles, the press release said.
The prints are on an almost-vertical slope due to the formation of the Alpine chain.
But when the dinosaurs walked through the area, it was formed of tidal flats that stretched for hundreds of kilometers, and the environment was tropical.
"The tracks were made when the sediments were still soft and saturated with water, on the broad tidal flats surrounding the Tethys Ocean," ichnologist Fabio Massimo Petti said, referring to a prehistoric ocean.
"The plasticity of those very fine calcareous muds, now transformed into rock, has in areas preserved truly remarkable anatomical details, such as impressions of the toes and even the claws," he said.
The footprints were then covered by sediments, which protected them, but with the uplift of the Alps and the erosion of the mountainside, they have been brought back into view.
"As the layers containing the tracks are diverse and overlapping, we have a unique opportunity to study the evolution of animals and their environment over time," geologist Fabrizio Berra said.
"Like reading the pages of a stone book."
