Traces of the fastest dinosaur ever discovered in Mongolia by a team of archaeologists

A recent palaeontological discovery is fundamentally reshaping our understanding of theropods. The analysis of ancient tracks suggests that one of the fastest dinosaurs may have lived during the Cretaceous period, raising new questions about the capabilities of predatory prehistoric creatures.

A 120-million-year-old trackway discovered in Mongolia sheds new light on the locomotion of theropods. According to the fossilised footprints, these may belong to the fastest dinosaur ever identified, capable of running at astonishing speeds – roughly comparable to that of a modern professional cyclist, reports IFLScience.

How fast were dinosaurs really?

Dinosaurs are often imagined as enormous, sluggish creatures, but a new palaeontological discovery significantly nuances this image. Based on fossilised footprints dating from the Cretaceous period, researchers have identified the tracks of what is believed to be the fastest theropod known to date. The footprints are attributed to a medium-sized predatory dinosaur that may have reached speeds of around 45 kilometres per hour while running.

This pace is not only exceptional in the context of dinosaurs but is also remarkable by modern standards, roughly equivalent to the speed of a professional cyclist.

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The fastest dinosaur’s tracks found in Mongolia

The footprints were discovered in Mongolia within a Lower Cretaceous sedimentary layer, meaning the animals that left them lived approximately 120–130 million years ago. What makes the site particularly remarkable is that it contains not one but two distinct trackways.

One of these is attributed to a large-bodied theropod dinosaur, which researchers associate with the species Chapus lockleyi. This animal appears to have been moving at a calm, walking pace.

The other trackway, however, indicates far more dynamic movement: it was made by a medium-sized, as yet unidentified prehistoric animal, classified within the Eubrontidae group, and it may represent the fastest dinosaur that ever lived.

How is a dinosaur’s speed calculated?

The study of fossilised footprints falls within the field of ichnology, which analyses traces left behind by ancient organisms. To estimate a dinosaur’s speed, researchers first assessed the animal’s size and stride length, then compared these measurements to its estimated hip height.

Based on the resulting so-called relative stride length, scientists can distinguish between walking, trotting and running. Walking typically falls below a value of 2, while running begins above 2.9. In the case of the medium-sized theropod examined here, this value was an astonishingly high 5.25, clearly indicating sprinting.

Additional details of the footprints further support the conclusion of extraordinary speed. The impressions are particularly pronounced at the toes, while heel marks are almost entirely absent – a pattern that, in modern animals as well, is characteristic of fast, explosive running. Moreover, the trackway is almost perfectly straight, suggesting that the animal was not manoeuvring but moving forward at maximum speed.

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What does all this reveal about theropods?

The discovery aligns well with previous biomechanical models, which suggest that large-bodied theropods tended to move more slowly, while smaller and medium-sized predators were capable of exceptionally fast running. This case provides particularly strong evidence that these theoretical models are supported by real-world data derived from fossilised footprints.