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Scientists’ understanding of Late Cretaceous ecosystems is changing as a result of an amazing finding made in the untamed centre of Bolivia. The biggest known concentration of dinosaur footprints ever discovered is found in a site called Carreras Pampa in Torotoro National Park. There are an astounding 16,600 tracks there, all of which were left by theropods, Tyrannosaurus rex’s predatory cousins.This 7,485-square-meter area only has carnivore prints, in contrast to other fossil sites that frequently show a combination of herbivores and carnivores. Not a single sauropod. No dinosaurs with duckbills. Just wave after wave of footprints preserved in soil from the Maastrichtian era, shortly before dinosaurs disappeared from Earth, with sizes ranging from less than 10 centimetres to more than 30.
Inside the discovery: What 16,600 dinosaur tracks tell us about prehistoric life
Research published in the open-access journal PLOS ONE uncovers an ancient assembly of predator species from a now-extinct lakeshore ecosystem. The Carreras Pampa site now stands as the largest dinosaur tracksite ever identified, eclipsing long-standing records from other continents.On a single stratigraphic surface, researchers found 280 swim pathways, 289 solitary prints, and 1,321 continuous trackways. Over 1,378 swim footprints were recorded by the study, some of which showed alternating left-right limb movement. This is direct proof of dinosaur swimming behaviour, a rare occurrence in the fossil record that was published in Communications Biology.Toe splay, tail drag marks, and even little turns or stops have been seen on several of the tracks. Because of the carbonate-rich substrate and low-energy depositional environment, all of this information is preserved in great detail.Some of the deepest impressions show that larger creatures were pushing into soft mud, while shallow ones suggest lighter creatures or harder terrain nearby. Certain trackways show more than just movement. In contrast to previous notions that most dinosaurs held their tails aloft for balance, over 30 trails had continuous tail drag marks, which are uncommon physical evidence that some dinosaurs allowed their tails to brush the earth.In other places, shallow swim tracks exhibit regular propulsion patterns, indicating that the dinosaurs were at least partially floating when they crossed flooded areas of the terrain. Multiple trackways overlap and connect in some places, suggesting frequent movement via small corridors or group activities.
Mystery of 16,600 dinosaur tracks
All documented tracks come from bipedal carnivores. The ecological reason for this gathering of carnivores is still a mystery.A behaviourally separated hunting area, scavenger aggregation close to a declining water source, or selected preservation in an area that carnivores disproportionately exploited are some of the hypotheses that the study team highlights but could not clearly propose.None, however, can account for the lack of prey species over an area of about 7,500 square meters.
