Unusual impressions on a rock face in Italy could represent tracks left by sea turtles fleeing an earthquake 83 million years ago. Free climbers discovered over 1,000 prints on limestone from the Cretaceous period. While researchers propose a biological origin, one expert questions their authenticity.
In the off-limits slopes of Monte Cònero on Italy's east coast, free climbers stumbled upon strange markings on a rock face. These features, numbering more than 1,000, appear in two spots: one over 100 meters above the current ocean level and another on La Vela beach after a shelf collapse. The rock consists of Cretaceous limestone formed from fine sediments on a shallow seabed around 83 million years ago.
Photographs of the site reached Alessandro Montanari at the Geological Observatory of Coldigioco in Italy, prompting a survey with park permission using foot access and drones. Montanari's team suggests the prints were made by sea turtle flippers. They eliminated fish, plesiosaurs, and mosasaurs as possibilities, given the ocean's vertebrate inhabitants at the time.
For the tracks to preserve on the soft seafloor, rapid burial was essential, likely from seismic activity. Montanari hypothesizes: “[It may have been] a strong earthquake, which scared the bejesus out of these poor animals who were peacefully hanging around the nutrient-rich shallow water environment.” He adds, “They all swim in panic towards the open sea on the west of the reef, and some of them reached the oozy seafloor, leaving their paddle prints.”
The idea remains a hypothesis, with plans to consult ichnologists for trace fossil analysis. Anthony Romilio from the University of Queensland notes that, if confirmed as turtle traces, they would be the world's most numerous. However, without direct site access, he doubts their origin: “The surface marks do not show the spacing, rhythm or anatomy expected from sea turtle flipper strokes. I am of the opinion they are not of biological origin, but are instead abiotic structures.”
The findings appear in Cretaceous Research (DOI: 10.1016/j.cretres.2025.106268).