The first dinosaur footprints found in Abruzzo testify to the presence of the largest theropod documented, up to now, in Italy. To discover them, a group of researchers from INGV and the Sapienza University of Rome. The results were published in Cretaceous Research (Elsevier)
The first dinosaur footprints discovered in Abruzzo by a group of researchers from the National Institute of Geophysics and Volcanology (INGV) are between 125 and 113 million years old and studied together with a team of ichnologists from the Sapienza University of Rome. The discovery enriches the panorama of dinosaur footprints present in our country, providing information on the animals that "walked" on the Italian beaches of the Cretaceous and on their behavior. The results of this find were published in the journal Cretaceous Research (Elsevier).
“The traces”, says Fabio Speranza, an INGV researcher, “are observable on an almost vertical calcareous surface, located at over 1900 m above sea level on Monte Cagno. The footprint surface can be reached (only in the absence of snow, therefore essentially in the summer and autumn months) after a hike of about two hours, starting from the town of Rocca di Cambio in the Province of L'Aquila. Among these was also found a trace of 135 cm in length which constitutes the testimony of the largest bipedal dinosaur that has ever been documented in Italy up to now".
Most of these footprints were impressed by one or more theropods (mainly carnivorous bipedal dinosaurs) which, as they walked, sank into the mud, most likely due to the weak consistency of the substrate. Other footprints, however, preserved in the center of the limestone surface, were left by a crouched theropod.
“The footprints, discovered by chance in the summer of 2006”, continues Speranza, “were found on a limestone surface of the lower Cretaceous age and suggested dinosaur footprints. But only in the summer of 2015, thanks to technological developments and collaboration with footprint experts from La Sapienza University, was it possible to give new impetus to research. A drone capable of carrying a digital camera and the use of the innovative digital photogrammetry technique have made it possible to reconstruct an accurate three-dimensional model starting from simple photographic images. Thanks to this technique, which originated in a cinematographic environment (for the film "Jurassic Park", 1993), it was possible to study the details of the footprints of the sub-vertical wall, bringing them back to a virtual environment that can be easily analyzed by computer. For a more precise dating, samples of the footprints and of the layers immediately above and below were taken".
Dinosaur footprints in Italy, studied for decades in our country and still continuously updated today, have allowed us to revolutionize our ideas on the geography of the Mediterranean area in the Mesozoic (between 200 and 65 million years ago).
"Contrary to what was believed in the past", explains Paolo Citton of the Sapienza University of Rome, "the footprints testify scenarios of repeated migrations of dinosaurs from the Gondwana continent (which brought together Africa, South America, Antarctica, India and Australia) to the carbonate platforms of Mediterranean area (an environment similar to today's Bahamas). As already discussed for some time by the ichnologists of 'La Sapienza', these passages were made possible by variations in sea level, processes on a global scale that take place over very long periods of time on our planet”.
Imperceptible over a short time, these changes can locally produce land emergence and establish new connections, as well as their interruption during a subsequent relative rise in sea level.
"The new footprints", concludes Citton, "could prove to be particularly valuable for additional information on the known composition of the Italian dinosaur fauna, with important repercussions also on the ecology and on the routes followed by these extinct animals".
Extended
A new Lower Cretaceous (lower Aptian) dinosaur tracksite, from the eastern side of Monte Cagno (Abruzzi, Italy), is described. Different styles of track formation are represented on the site surface. Most of the footprints are preserved as deep tracks, produced by trackmakers sinking into soft mud. Some tracks, better preserved than the others, are characterized by metatarsal impressions and were interpreted as the resting traces of a crouching theropod (based on their orientation and three-dimensional morphology). The 135 cm length of the track with metatarsal impressions indicates huge pedal proportions and represents the largest theropod trackmaker ever documented from the Mesozoic peri-Adriatic platforms of Italy.
The surface with theropod footprints on the eastern slope of Monte Cagno (L'Aquila), and related three-dimensional models obtained from digital photos acquired in flight